Restek Technical Articles

Collected from the Restek Advantage, thirteen thought-provoking essays offering insight into sample vaporization processes in gas chromatography, important splitless optimization concepts, and food for thought on lab practices, education, and food safety.
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Dr. Chris Marvin, of Environment Canada, discusses the challenges of analyzing brominated flame retardants, such as polybrominated diphenyl ethers, by LC/MS.
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Numerous articles have been published on faster methods for gas chromatography (GC), yet uncertainty remains on how best to speed up separations. Here, Dr. Hans-Gerd Janssen clarifies the confusion surrounding fast GC and recommends a strategic approach based on 3 steps: 1) minimizing resolution to a value just sufficient, 2) maximizing the selectivity of the chromatographic system, and 3) implementing a method that reduces analysis time while holding resolution constant.
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Metabolites are found in different concentrations in complex biological matrices and are very difficult to extract without compromising their structural integrity and relative abundances. Quality control in metabolomics means more than just taking care of chromatographic or mass spectrometry parameters. This article by Oliver Fiehn examines quality control as an attitude towards gaining reliable data, rather than an automatic procedure implemented in instrument software.
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Guard columns & retention gaps are used widely in gas chromatography (GC) but the differences between them are not always understood. Part 2 of this two-part editorial by Jaap de Zeeuw discusses guard columns & introduces a new segment coating technology that allows retention gaps & guard columns to be built directly in the same piece of tubing as the analytical column.
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Guard columns & retention gaps are used widely in gas chromatography (GC) but the differences between them are not always understood. Part 1 of this two-part editorial by Jaap de Zeeuw reviews the use of retention gaps & discusses critical factors affecting performance. This sets the background for Part 2, which details guard columns & introduces a new segment coating technology that allows retention gaps & guard columns to be built directly in the same piece of tubing as the analytical column.
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Can the Mystery Be Revealed?

Dr. Werner Engewald discusses the phenomenon of cross-over, or changes in elution order following modification of the GC temperature program. This effect has been observed for decades but the physio-chemical background still is not well understood. In this article Dr. Engewald explores the theory and potential explanations for the cross-over phenomenon.
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By Paul Silvis, Restek Founder & former Head Coach

In this editorial, founder and former CEO Paul Silvis explains some of the reasons for Restek’s success as a provider of chromatography columns and supplies. Restek will continue to be successful because, as an employee-owned company, we hold our future in our own hands. Customers will benefit because we can continue to respond to their ideas for the products and services they need to make their work easier.
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Guest Editorial by Robert L. Grob, Ph.D.

Sample preparation principles and techniques for gas chromatography are reviewed. Techniques include: static headspace, dynamic headspace, solid phase extraction and microextraction, distillation, stir bar sorptive extraction, Soxhlet, accelerated solvent extraction, pressurized liquid extraction, subcritical water extraction, microwave assisted extraction, ultrasonic extraction, and supercritical fluid extraction.
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Guest editor Dr. Phil Marriott tells us the three primary contributions ascribed to GCxGC are greater separation capacity, greater sensitivity, and a data presentation that permits identification of related compounds based on the molecular properties that control retention. The most significant advantage is separation power: to be able to resolve many more compounds immediately enables a much more complete ‘picture’ of the composition of a sample.
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Professor Jennings explains the consequences of ignoring those enclosures included with a new column, and offers simple, proven, preventive maintenance options that help avoid downtime.
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In his first contribution to the Restek Advantage Professor Walter Jennings discusses why analysts often encounter problems when replacing a capillary GC column, and provides a solution.
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Content previously published in Petro Industry News

New PLOT columns offer significantly reduced particle release, extending column lifetime and assuring highly reproducible retention times column-to-column. Improved applications for porous polymer, molecular sieve, and alumina columns.
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Content previously published in Petro Industry News

New MXT®-1HT SimDist GC columns outperform competitors, allowing more productive D6352 analyses. Here we demonstrate lower bleed levels and higher efficiency, improving resolution and assuring more samples can be run within method specifications.
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Content previously published in International Laboratory

Jaap de Zeeuw discusses recent advances in PLOT column technology in an International Laboratory article. New stabilization technology minimizes particle release, assuring more consistent flow and better performance for a number of applications.
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Content previously published in Petro Industry News

Rtx®-1 PONA columns are highly stable and can be run with helium or hydrogen under accelerated conditions. Restek has developed a new DHA method using Rtx®-1 PONA columns with hydrogen that can double refinery sample throughput.
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Content previously published in Petro Industry News

Restek's new D3606 column set outperforms TCEP columns for gasoline testing. The D3606 set has higher thermal stability and reliably resolves benzene from ethanol, resulting in more accurate quantitation.
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Using Siltek® and Sulfinert® Surface Treated Components

Refinery and natural gas samples often contain trace amounts of sulfur- and mercury-containing compounds, which can interfere with reactions, poison catalysts in petrochemical processes, and damage equipment. Because these compounds quickly react with stainless steel surfaces, accurate determination of these compounds is impossible when samples are collected and stored in untreated sample cylinders. Restek's Siltek® and Sulfinert® passivation techniques bond an inert layer into the surface of stainless steel, preventing active compounds from reacting with or adsorbing to the steel.
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Using metal columns to analyze glycerin in biodiesel offer significant performance advantages compared to fused silica columns, as shown in this evaluation.
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Data-Based Decisions Help Simplify the Choice

We evaluated our 100 meter x 0.25mm ID x 0.5df PONA column and equivalent columns from four other vendors, following ASTM D-6730 methodology (hydrogen carrier gas). Data and chromatograms presented here show that only the Restek PONA column performed to method specifications admirably. Column efficiency exceeded specification.
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Relative to helium as the GC carrier gas, hydrogen from a gas generator reduces gas costs, cuts analysis time by 50%, and reduces temperatures needed for eluting analytes — which increases column lifetime. Parker ChromGas® hydrogen generators are safe, convenient, reliable, and easy to use.
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Analysis of Total Glycerides in Biodiesel Oils by ASTM D-6584 Using the New MXT®-Biodiesel TG Capillary Column

The high temperatures required for biodiesel analysis by gas chromatography present a considerable challenge to analytical columns. Fused silica columns, even those rated for high-temperature tolerance, breakdown relatively quickly. Restek’s new MXT®-Biodiesel columns are more stable up to 430°C and offer excellent chromatography for glycerides. These columns are available in two configurations: factory-coupled to a 0.53mm retention gap, or with a built-in, leak-proof Integra-Gap™ retention gap.
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Using a Stabilwax® Capillary GC Column

As biodiesel fuel continues to stimulate interest worldwide as an energy source, several gas chromatographic methods have been developed to determine the quality of B100 fuel. Here we show excellent peak symmetry, resolution, and reproducibility for determining the fatty acid methyl ester (FAME) and linolenic acid methyl ester content in B100 biodiesel fuel, using European standard method EN 14103 on a Stabilwax® fused silica GC column.
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Using an Rt-Msieve™ 5A PLOT Column

A Restek PLOT column can be your best solution for difficult separations of gaseous analytes. Rt-Msieve™ 5A PLOT columns offer fast, efficient separation of argon/oxygen, hydrogen/helium, and other permanent gases, including permanent gases in refinery or natural gas. You can make difficult separations without subambient temperatures, e.g.: separate oxygen from argon to baseline in approximately 4 minutes.
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Exceptional Peak Symmetry, Using an Rtx®-Biodiesel GC Column

Glycerin is a notoriously difficult challenge in GC, particularly at the levels involved in biodiesel oil analysis, but an Rtx®-Biodiesel column provides a symmetric peak that makes quantification easier and more reliable. The column performs well at elevated temperatures: peaks for glycerin and glycerides exhibit minimal tailing, and bleed is low at 370°C, as specified in European method DIN EN14105.
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Using Restek’s Robust Rtx®-Biodiesel Capillary GC Column

We challenged our Rtx®-Biodiesel column with analysis for glycerin in biodiesel according to method ASTM D-6584-00. Excellent linearity was established for glycerin, triolein, monolein, and diolein, with r2 values exceeding the method criteria for all compounds. Mono-, di-, and triglycerides resolved well from other compounds in B100 biodiesel oil. Column performance was strong at high temperatures, with low bleed even at 380°C. An Alumaseal™ connector and guard column were used to extend column life.
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Using an Rxi™-1ms Column and Sulfur Chemiluminescence Detection

Ultra-low bleed and exceptional inertness assure complete separation of sulfur compounds (hydrogen sulfide, carbonyl sulfide, dimethyl sulfide, mercaptans) on our new column, with excellent peak shapes and reliable quantification at ppbv levels. A Sulfinert® treated sampling/transfer system assures no adsorption losses of these very reactive compounds.
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Recovery of a 17ppbv test standard of hydrogen sulfide exceeded 85% after 54 hours in a Sulfinert®-treated cylinder; recoveries of methyl mercaptan, ethyl mercaptan, carbonyl sulfide, and dimethyl disulfide exceeded 90%. A Sulfinert®-treated sampling/transfer system can assure accurate sulfur content data for natural gas, beverage-grade carbon dioxide, or other samples.
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In process GC analyses, this material offers unique selectivity for the difficult-to-separate saturated and unsaturated C4 hydrocarbons, eluting cis-2-butene before 1,3-butadiene. Innovative bonding chemistry assures batch-to-batch reproducibility, excellent thermal stability, and long column life.
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n-Octane on Res-Sil™ C packing provides excellent, reproducible separations of volatile hydrocarbons in petroleum products, including the difficult-to-separate saturated and unsaturated C4 compounds. An OPN on Res-Sil™ C column separates C1-C5 hydrocarbons in half the time required by alternative columns.
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New Rxi®-5Sil MS columns produce consistent results for amphetamine—even after 400 injections of derivatizing reagent—resulting in less time and money spent on column maintenance and replacement.
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A new LC method for analyzing ethanol metabolites using ion-pairing provides higher retention, faster analysis times, and improved MS sensitivity for EtG and EtS, compared to conventional methods.
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Conventional techniques for vitamin D analysis often lack adequate sensitivity, specificity, and speed. This LC/MS/MS assay results in highly symmetric peaks that elute in just 5 minutes.
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The headspace (HS) analysis of gamma-hydroxybutyrate (GHB) described here reduces contamination and eliminates time-consuming derivatization. Confirmation testing using an Rtx®-5MS column, provides definitive results in less than 7 minutes.
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Using a System Suitability Test Mix for Drug Analysis

Restek and Applied Biosystems have developed a system suitability mix specifically for drug testing that contains compounds covering a wide range of molecular weights, polarities, and retention times. This mix is designed to verify system performance and identify problems. Data are automatically compared to expected results by Cliquid® Drug Screen & Quant Software. Use this mix to assure system performance, improve data quality, increase sample throughput, and simplify troubleshooting.
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Using the JASCO X-LC System

This application note describes a 6.1 min method for identifying a mixture of 8 sex hormones using Jasco X-LC. The compounds are separated by a gradient elution of water and acetonitrile on a Restek 1.9µm Pinnacle DB Biphenyl column.
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Clean Up Procedure Improves Chromatography and Reduces Maintenance

Analyzing amphetamines by GC/MS can be challenging whether they are derivatized or underivatized. Here we evaluate the effects of several sample pretreatment methods. The resulting method reported here produces symmetric peaks while reducing the amount of contamination that can enter the GC system. This method ensures accurate area count reproducibility, a clean GC system, and a stable baseline, even for GC/MS work.
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Quantify an Order of Magnitude below Typical Methods

An LC/MS/MS method for benzodiazepines was developed and offers several advantages over other techniques: minimal sample preparation, fast analysis times, multiple reaction monitoring transitions for quantification and confirmation, and sensitivity down to 0.10-10ng/mL. This method uses the Allure® PFP Propyl stationary phase, which retains compounds long enough to minimize matrix interferences and chromatographically separate compounds that share the same precursor ion.
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Using LC/MS/MS & an Allure® PFP Propyl HPLC Column

The analysis of opiates typically requires derivatization when using gas chromatography/mass spectrometry (GC/MS), which leads to longer sample preparation time. An alternative liquid chromatography tandem mass spectrometry (LC/MS/MS) method presented here eliminates sample derivatization and offers fast analysis times, resulting in increased sample throughput. In addition, the Allure® PFP Propyl column used here produces baseline resolution for compounds that have very similar mass spectra.
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Improve GC Separations with Derivatization

Derivatizing compounds is often necessary to obtain acceptable, reproducible results. Here we review reasons for derivatization and the three basic types of derivatization reactions for gas chromatography: silylation, acylation, and alkylation. An example procedure for derivatizing hormones, including chromatography, is given.
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Using a 12m x 0.20mm ID 0.33µm Rxi®-5ms Column

Screening for evidence of marijuana use is typically done using an immunoassay method to detect derivatives in urine, but confirmation of positive results requires GC/MS. Here we describe a GC/MS method, using an Rxi®-5ms column, that resolves all major cannabinoid metabolites to baseline and exhibits very low bleed, even at 300°C. We also prolonged column life by baking at 340°C to remove derivatization by-products.
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Using Restek Columns in Headspace GC or GC/MS Systems

We adapted Rtx®-BAC1 and Rtx®-BAC2 columns, with their proven performance in blood alcohol analysis, to a screening procedure for GHB, followed by confirmation and quantification on a highly inert Rxi®-5ms column. Use of a system and column already in use for blood alcohol analysis eliminates the need for additional equipment, reduces system maintenance, and allows rapid and reliable screening, confirmation, and quantification.
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These exempted materials include amphetamine and methamphetamine, barbiturates, benzodiazepines, cannabidiol and cannabinol, cocaine/cocaine metabolites, methadone/methadone metabolites, opiates/opiate metabolites, and other drugs, a range of blood alcohol standards from 0.010g/dl to 0.4g/dl, and a blood alcohol resolution control standard.
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Exempted Drug of Abuse Reference Materials
Blood Alcohol Standards
Blood Alcohol Mix Resolution Control Standard

Using the New Rxi®-1ms Column

GC/MS analysis of urinary steroid hormones is a demanding application, and the Rxi®-1ms column meets the requirements for low bleed and inertness better than any column we have tested. We analyzed a variety of derivatized steroid sex hormones in less than 25 minutes, with excellent resolution and symmetric peaks. At 300°C or above, bleed from the Rxi®-1ms column was negligible.
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Basic drugs can interact with active sites on the surface of the inlet liner, reducing responses. The combination of a base-deactivated liner and a base-deactivated Rtx®-5Amine column ensures the greatest responses in analyses for these compounds.
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An Rxi®-5ms column will resolve acidic/neutral or free basic drugs under one set of conditions. There is no interference from column bleed — not even at 330°C. This is one of the first published applications for our new family of Rxi® columns.
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A high-organic mobile phase and an Allure™ PFP Propyl column offers adequate retention, short analysis times, and excellent sensitivity for cocaine and cocaine metabolites, without mobile phase modifiers. Target compounds are eluted within 3 minutes, with excellent sensitivity at 5.0pg on-column.
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New Semivolatiles Wool liners are designed specifically for semivolatiles analysis and result in more accurate results at lower levels, compared to similar products.
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Sample throughput for PBDE analysis can be significantly increased using a 15m Rtx®-1614 column. Excellent responses and peak shapes are obtained for all congeners, including BDE-209, in just 20 minutes.
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Ultra II Aromax and Ultra C8 columns were determined to provide better separations for the routine analysis of explosives by LC than conventional phases.
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Switching to a methanol based mobile phase for polycyclic aromatic hydrocarbon analysis—using the method shown here—is an effective way to save money by reducing acetonitrile consumption.
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As labs operate in an extremely competitive market, the demand for more sensitive multiresidue pesticide methods is increasing. Here we demonstrate linearity down to 10pg on-column for a wide range of pesticides differing in volatility, compound class, and degree of activity. The inertness of the Rxi®-5Sil MS column ensures linear performance and more accurate low level quantification for multiresidue pesticide methods.
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Programmable temperature vaporization inlets are versatile, yet normally do not accommodate on-column injection. Now, using a PTV On-Column liner, the capabilities of PTV can be expanded to include true on-column injections.
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Estrogens and conjugates, including estradiol sulfates and estradiol glucuronides, were separated and detection limits were lowered using an Allure AK column and an LC/MS/MS system. Initial results from large volume sample testing are also reported.
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Reliably Analyze Acetamide Herbicide Degradates by LC/MS/MS

An optimized EPA Method 535 procedure offers superior sensitivity for the ethanesulfonic acid (ESA) and oxanilic acid (OA) degradates of chloroacetanilide herbicides alachlor, acetochlor, and metolachlor. Alachlor ESA and acetochlor ESA isomers are reliably resolved, and the procedure is simplified with a full line of Method 535 products, including reference standards, solid phase extraction cartridges, and HPLC columns.
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Using a New Rtx®-1614 Column for PBDE Analysis

The new Rtx®-1614 column is ideal for analyzing polybrominated diphenyl ethers (PBDEs) according to EPA Method 1614 due to its selectivity, sensitivity, and inertness. Data show this column meets the method requirements for resolution of critical pairs, tailing factors, and retention. Congeners 49 and 71 are fully resolved and a greater response for BDE-209 is seen. Optimized conditions can improve performance.
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With UHPLC and HPLC Column Options

Here we analyze polycyclic (polynuclear) aromatic hydrocarbons (PAHs) from the US EPA, European Union (EU), and Portugal lists by UHPLC and HPLC. Procedures shown use two optimized stationary phases (Pinnacle™ DB PAH and Pinnacle™ II PAH) and provide 3.5 to 6 minute analyses, allowing labs to achieve significantly faster sample throughput.
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Using the Rtx®-Dioxin2 Column

The Rtx®-Dioxin2 column has a unique selectivity for dioxins and furans, including specificity for 2,3,7,8-TCDD and 2,3,7,8-TCDF. Here we characterize all 136 tetra- through octachlorine dioxins and furans and define all possible coelutions. While commonly used cyanopropyl columns are limited by a low maximum operating temperature of 240°C, the Rtx®-Dioxin2 column is stable up to 340°C, extending column lifetime and improving the analyses of dioxins and furans.
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The use of carbon disulfide (CS2) extraction as an air monitoring method for vapor-phase organic compounds (VOCs) is fundamentally limited with respect to detection limits. Thermal desorption (TD) is a complementary gas extraction technique whereby sorbent tubes are heated in a flow of carrier gas. Trapped vapors desorb from the sample tubes into the gas stream and are transferred into the GC/MS analyzer. Here, we summarize the key advantages of thermal desorption versus solvent extraction.
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On New Rtx®-CLPesticides & Rtx®-CLPesticides2 Columns

The Rtx®-CLPesticides and Rtx®-CLPesticides2 column pair is an excellent choice for chlorophenoxyacid herbicide analysis. Now, with an optimized film thickness for the 0.32mm ID version, this difficult analysis can be made in less than 13 minutes on both the primary and confirmation columns. Near baseline resolution is achieved for all analytes except for bentazon/picloram on the Rtx®-CLPesticides column; however, this pair is fully resolved on the Rtx®-CLPesticides2.
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GC/MS SIM Analysis with the New Rxi®-5Sil MS Column

Semivolatiles methods, such as EPA Method 8270, place stringent demands on gas chromatography (GC) columns. Here we demonstrate the performance of Rxi®-5Sil MS columns for semivolatiles analysis in terms of bleed, efficiency, and activity. Excellent sensitivity and resolution are seen, even for difficult PAHs such as benzo(b)fluoranthene & benzo(k)fluoranthene, and indeno(1,2,3-cd)pyrene and dibenzo(a,h)anthracene. Both basic and acidic compounds show good response even at low levels.
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Using New Rxi®-5Sil MS GC Columns

Semivolatiles methods, such as EPA Method 8270, place stringent demands on gas chromatography (GC) columns. Here we evaluate the performance of Rxi®-5Sil MS columns for semivolatiles analysis in terms of bleed, efficiency, and activity. We demonstrate excellent sensitivity and resolution, even for difficult PAHs such as benzo(b)fluoranthene & benzo(k)fluoranthene, and indeno(1,2,3-cd)pyrene and dibenzo(a,h)anthracene. Both basic and acidic compounds show good response even at low levels.
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Using the New Allure® AK HPLC Column

The new Allure® AK HPLC column was developed specifically for the analysis of aldehydes and ketones, including the 13 carbonyl compounds specified in the California Air Resources Board (CARB) Method 1004. The data shown in this article demonstrate excellent resolution, even of buteraldehyde and methyl ethyl ketone (MEK), in less than 12 minutes using a 200mm Allure® AK HPLC column.
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On New Rtx®-CLPesticides & Rtx®-CLPesticides2 Columns

Increasing sample throughput is an effective way to reduce operating costs for environmental labs. Here we introduce new film thicknesses for the Rtx®-CLPesticide and Rtx®-CLPesticide2 GC columns, optimized for complete separations and short analysis times. Using these new columns, all US EPA Method 8081 organochlorine pesticides are resolved in <9 min. We also show complete separation of these compounds in <5 min. using these columns and a Gerstel MACH column heating system.
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Separate New PAHs Quickly Using the Rxi®-17 GC Column

Polynuclear aromatic hydrocarbons are a significant, and wide-spread, source of pollution. The US EPA mandates testing of the 16 PAHs they designate as most hazardous; the target list in other countries is expanding and includes new compounds that are difficult to separate. Here we demonstrate the ability of the Rxi®-17 column to effectively resolve dibenzo pyrene isomers, as well as to separate benzo(j)fluoranthene from benzo(b)fluoranthene and benzo(k)fluoranthene.
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Liner choice is a critical decision in semivolatiles analysis. Liners containing wool packing are recommended to minimize molecular weight discrimination. Attributes of different types of liners, including the Drilled Uniliner, are discussed.
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Using Rtx®-CLPesticides / Rtx®-CLPesticides2 Columns

Unique selectivities make the Rtx®-CLPesticides / Rtx®-CLPesticides2 column pair an excellent choice for analyzing pesticides by US EPA Method 8081, or equivalent methods. A 0.53mm ID guard column allows sample injection onto high-efficiency 20m x 0.18mm ID thin film columns, for baseline resolution in greatly reduced analysis time. Sharp, symmetric peaks help assure reliable quantification data.
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Using the Rtx®-5Sil MS Capillary GC Column

Combining an optimized stationary phase and deactivation that assures unsurpassed inertness and excellent responses for active analytes, Rtx®-5Sil MS columns address the challenging demands of semivolatiles analyses. Phenyl rings in the polymer backbone stiffen the siloxane chain, ensuring thermal stability and reducing bleed. Selectivity is similar to that of conventional 5% diphenyl phases, but improved, e.g.: separation of isomers benzo(b)- and benzo(k)fluoranthene is increased.
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Using a 20m x 0.18mm x 0.30µm Rxi®-5ms Column

We developed the 20m x 0.18mm x 0.30µm Rxi®-5ms column to balance the demand for shorter analysis times with the need to maintain both column capacity and column efficiency. Here we establish conditions for eluting more than 90 semivolatiles, including 7 surrogates and 6 internal standards, in less than 12 minutes. Benzo(b) and benzo(k)fluoranthene were resolved well and sample throughput was improved by 75%. This highly inert, low bleed column is ideal for GC/MS analysis.
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Using a Pinnacle™ II PAH Column

Nineteen polycyclic aromatic hydrocarbons (PAHs), including benzo(b) and benzo(j)fluoranthene, were fully resolved using a Pinnacle™ II PAH column. Greater sensitivity was achieved by coupling UV and fluorescence detection. This HPLC method offers improved resolution compared to standard GC techniques.
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For Low Level GC/MS Analyses

Our new, nonpolar, 100% dimethyl polysiloxane Rxi®-1ms column offers the same superior inertness, ultra-low bleed, and excellent batch to batch reproducibility exhibited by our Rxi®-5ms column. We analyzed a complex mixture of semivolatile analytes, including both acidic and basic compounds, at levels as low as 0.5ng on column. The selectivity, analyte breakdown, peak symmetry, and bleed results shown here are strong recommendations for the new column.
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Excellent Responses at 10ng On Column, Using an Rxi®-5ms Column

Using this new column, resolution and peak shapes for 88 semivolatile compounds commonly analyzed in drinking water are exceptionally good at 10ng each on column. Because the Rxi®-5ms column performs well with analytes in a diverse range of chemical classes, we highly recommend it for analyzing complex mixtures of semivolatiles.
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Using an API 3200™ Mass Spectrometer and an Ultra Quat HPLC Column

Developed through collaboration with scientists at AB/MDS Sciex, this analysis allows complete resolution of paraquat and diquat with a simple, isocratic mobile phase. It is significantly faster than conventional methodologies and, with detection limits of 5ppb for paraquat or 0.1ppb for diquat, sensitivity is superior — without preconcentration.
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Drinking Water: US EPA Method 525.2

Listed reference mixes include organochlorine pesticides, organonitrogen pesticides, organophosphorus pesticides, PCB congeners, internal standards, surrogates, a performance check mix, and more.
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The newest members of our new line of Rxi® columns, Rxi®-1ms columns, offer the same outstanding inertness, ultra-low bleed, and batch-to-batch reproducibility as our Rxi®-5ms columns. Rxi®-1ms columns provide excellent selectivity and symmetric peaks for the diverse chemicals that can make up a semivolatiles sample.
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Exceptional inertness and ultra-low bleed enable an Rxi®-5ms column to resolve sub-1ng quantities of acidic or basic analytes under a single set of conditions. In this example analysis, an Rxi®-5ms column separated 93 target analytes in US EPA Method 8270D in less than 18 minutes.
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New manufacturing processes for our Massachusetts TPH solid phase extraction cartridges reduce extractable contaminants almost to blank levels, and assure more reliable fractionation of aliphatics from aromatics. Large, uniform lots of silica reduce the frequency of verifying fractionation results.
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This mix includes all 19 volatile compounds on the Canadian Drinking Water List. We recommend using an Rtx®-VMS column for the analysis, to assure sharp peaks for early eluters and resolution of the heavier compounds.
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An Rtx®-VMS column provides rapid, baseline resolution of most volatile analytes in the CLP OLM 04.1 analysis for groundwaters or drinking waters from Superfund sites. A particularly challenging stipulation of the method, 90% resolution of the gaseous components, is easily attained.
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The recent establishment of a 1µg/g safety threshold for melamine in infant foods has led to an immediate need for more sensitive methods. Here we established GC/MS conditions for highly reproducible analyses and evaluated the effectiveness of both solvent-based and matrix-matched standards. Using this method, melamine and cyanuric acid were reliably detected at and below 1µg/g in infant formula.
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Using a Fraction of the Solvent with dSPE

Simplify and speed up sample preparation with Restek dispersive SPE tubes! Here we show the extraction and clean-up of pesticide residues from olive oil samples — twice as fast as gel permeation chromatography (GPC), with only a fraction of the solvent required for conventional solid phase extraction (SPE).
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Estimating cholesterol in food products is complicated, but often is part of the authentication testing of label claims regarding egg content. The method shown here simplifies fraud detection by incorporating glyceride testing. Easy comparison of the chromatographic profiles of egg and egg product (pasta) samples can be made using an Rtx®-65TG column, which is specifically tested to assure excellent separations and a reliable performance for glycerides.
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Using QuEChERS SPE Tubes

Quick, Easy, Cheap, Effective, Rugged, and Safe, the QuEChERS ("catchers") method for extracting pesticides from food is based on USDA research and employs a novel dispersive solid phase extraction cleanup (dSPE). QuEChERS methods are convenient, rugged methods that simplify extract cleanup, reduce material costs, and improve sample throughput. Here we demonstrate the effectiveness of QuEChERS sample cleanup using a multiresidue analysis of pesticides on strawberries.
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Using an Ultra Carbamate HPLC Column

EPA Method 531.1 addresses the analysis of carbamate pesticides in water, but not in more complex matrices, which often contain interferences and require time-consuming sample preparation. We developed an easy, accurate screening method for carbamates in a complex matrix using an Ultra Carbamate HPLC column in conjunction with the Leco Unique TOF- MS. This method requires no sample preparation and provides fast analysis times, significantly increasing sample throughput.
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Lower Detection Limits with Latest Technology

Thermal desorption offers an automatic, high-sensitivity alternative to conventional liquid extraction methods for aroma profiling by GC/MS. It allows vapor profile constituents to be cleanly separated from the sample matrix and often facilitates selective purging of volatile interferences. This ensures that the vapor profile analyzed is most representative of the aroma perceived by consumers and that key compounds can be identified and measured at the lowest levels possible.
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Modified Conditions Save Costs and Reduce Maintenance

Melamine contamination was implicated in a large pet food recall that occurred in 2007 when animals died after eating contaminated pet food. Here, a modified GC/MS method, based on an FDA method, was used to analyze for melamine & related compounds cyanuric acid, ammelide, and ammeline in dry cat food. Analytes were easily identified by retention time matching and mass spectra.
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Using Headspace GC/MS and an Rxi®-5ms Capillary Column

Chromatographic methods for garlic and garlic powder are used by the food and dietary supplement industries to monitor product quality. Here we present a headspace gas chromatography mass spectrometry (HS GC/MS) method for garlic flavor and odor components using an Rxi®-5ms column. This method eliminates sample preparation making the bench work simple and fast. The experimental set-up is ideal for both screening analysis and low-level trace analysis.
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Using Water-Compatible Allure® or Ultra C18 Columns

Commonly used organic acid methods (e.g. AOAC method 986.13) depend on reversed phase HPLC and C18 columns, however these columns are vulnerable to phase collapse when used with the aqueous mobile phases necessary for optimal organic acid analysis. Restek’s Ultra Aqueous C18, Allure® Aqueous C18, and Allure® Organic Acids columns all withstand phase collapse and resolve organic acids in a 100% aqueous mobile phase, compared to a conventional C18 column which shows a complete loss of retention.
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Using LC/MS/MS and an Ultra C18 Column

Nitrofurans are a class of veterinary antibiotics used to increase growth rate and prevent or treat disease in animals. Determining levels of nitrofurans in animal tissue, or even products such as honey, is important in studying drug resistance and allergies in humans. The Ultra C18 HPLC column is an excellent choice for LC/MS/MS analysis of nitrofurans at low levels in complex matrices such as honey. Here we show excellent sensitivity, resolution, and peak shape at trace levels.
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Essential oils are complex natural products containing many components across a wide concentration range. This complexity makes their analysis especially challenging. Many methods involve sample dilution to prevent syringes from clogging but this is not always necessary and can compromise analytical quality, especially for less abundant compounds near the solvent peak. Here we provide steps for optimizing your method to allow essential oils to be analyzed without dilution.
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Using an Ultra Aqueous C18 HPLC Column and Unique® TOFMS

An Ultra Aqueous C18 column enables you to use the conditions most effective for this analysis: gradient elution in high aqueous mobile phases. The C18 chains will not collapse in the presence of a high water content. Use this chromatographic system to extract data for specific compounds of interest and to manually inspect spectra for phenolic glycosides, esters of phenolic acid, or other compounds.
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Excellent Sample Throughput with an Rxi™-5ms Column

Conditions are established for analyzing both derivatized and underivatized cholesterol on a highly inert Rxi™-5ms column. Methods described include both an isothermal analysis for use when interferences are minimal, but sample throughput is critical, and a temperature program for use when separation of analytes from contaminants or interfering compounds is the primary concern. Results for both derivatized and underivatized samples were highly reproducible.
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Using a Leco Unique® LC-TOFMS Systemand an Ultra Aqueous C18 Column

We separated flavonoids in cacao or cocoa powder samples and returned conditions to the initial mobile phase composition in 15 minutes. For compounds common to both samples, retention times were equal to within 0.01 seconds. Flavonoid marker compound profiles for 38%, 49%, and 65% cacao were easily distinguished.
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A 10-meter, 0.10mm ID, 0.10µm film Rtx®-5 column reduces analysis time for bergamot oil or patchouli oil by 80%, for five-fold greater sample throughput and sharply reduced cost per analysis. Sample resolution is unchanged for bergamot oil and is slightly improved for patchouli oil.
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The highly polar Rt-2560 stationary phase has the selectivity needed for resolving cis and trans FAME isomers to comply with US FDA food labeling guidelines. Restek reference materials will help you accurately characterize your materials.
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Using an Ultra Aqueous C18 column, a simple, isocratic mobile phase, and detection at two UV wavelengths (488nm for Sudan I and II and 520nm for Sudan III and IV), the four dyes are separated and identified in approximately 20 minutes.
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Sudan dyes are illegal as food additives according to the US FDA and the EU. A reversed phase HPLC separation of Sudan I, Sudan II, Sudan III, and Sudan IV (Scarlet Red) is simple, yet efficient, requiring only a simple mobile phase, isocratic elution, and detection at two wavelengths. An Ultra Aqueous C18 column provides the selectivity needed to assure the separation.
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Illegal use of malachite green (MG), an inexpensive fungicide, can allow MG to enter water cycles, where it is easily absorbed by fish tissue, and thus enters the human food supply. Reversed phase HPLC often is used to analyze for MG and its stored metabolite, leucomalachite green. Methods that facilitate detection of both compounds are discussed.
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Significant savings can be obtained without the costly upgrade to UHPLC. This famotidine example illustrates how a 90% reduction in analysis time and solvent volume resulted from strategic HPLC column choices.
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Column choice is a critical factor in successfully transferring methods between UHPLC and HPLC. Here, we discuss the column qualities that contribute to the successful integration of UHPLC technology.
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Novel column chemistries are a simple change in an already budgeted consumable that can lead to optimized and more reliable methods—giving a fast return on a minimal investment.
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The Pinnacle® DB Biphenyl column offers enhanced retention and alternate selectivity for aromatic, unsaturated, and sulfur-containing hydrophilic compounds. Here we demonstrate significantly greater retention of sulfone- and sulfoxide-containing drug probes, compared to phenyl, phenyl hexyl, and alkyl (C18) columns. Only the Biphenyl column, using pi-pi interactions, separated both test probes to k′ > 2, the level needed to ensure separation from unretained matrix contaminants.
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Two options for the analysis of PGIs in API have been developed by Merck and Restek to meet different laboratory needs. The first option is a fast method for the analysis of sulfonate esters on the Rxi®-5Sil MS column. The second option is a comprehensive method for the analysis of both sulfonate esters and alkyl halides on the Rtx®-200 column. Both methods require very little sample preparation, which helps increase laboratory productivity.
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Analyzing basic compounds can be somewhat troublesome on traditional alkyl stationary phases, namely conventional C18 columns. This is largely due to the interaction of analyte molecules with silanol groups present on the silica surface. To better understand the workings of silanol interactions, it is important to consider the composition of the support material. Silica is the most commonly used support in the production of HPLC columns, mainly because it is well-suited to high-pressure chromatographic separations, giving high efficiencies and good reproducibility. Silica offers bed and pressure stability and is highly porous, which ultimately gives rise to its large surface area, increased bonding capacity and high peak efficiencies. Silica also possesses widely-studied and effective bonding chemistries, making possible diverse analyte selectivities through a wide variety of bonded stationary phases.
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A Versatile Column with Many Applications

The Ultra IBD HPLC column addresses the inherent problems attributed to linear alkyl phases, providing excellent peak shape for basic compounds and heightened retention of hydrophilic compounds. Here we demonstrate the versatility of this polar embedded column, and its ability to overcome some of the common limitations of conventional C18 columns. The versatility of the Ultra IBD makes it an excellent tool for the practicing method developer.
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Using Fully Scalable Pinnacle™ DB Columns

Ultra High Pressure Liquid Chromatography (UHPLC) is a rapidly growing technique that can provide faster analysis times. Scaling conventional HPLC methods down to UHPLC can be an effective way to take advantage of shorter run times and increase sample throughput. Here we review the factors that must be considered when scaling down an existing method. A sulfonamides method transfer is used as an example; chromatograms and formulas for all required calculations are included.
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Faster Sample Throughput on a 1.9µm Pinnacle™ DB column

Small particle HPLC columns can offer faster analysis times but only if the particle size distribution is tightly controlled. Restek’s 1.9µm Pinnacle™ DB columns have tight, symmetric particle size distributions and contain no particles less than 1µm. Here we demonstrate how our stringent quality requirements translate into faster, more reproducible results compared to competitor columns. Greater column efficiency and reproducibility mean faster throughput and more consistent results.
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Satisfy New Method Requirements with Restek Columns and Standards

The United States Pharmacopeia recently revised the general chapter on residual solvent analysis, USP <467>, to mirror the International Conference on Harmonization (ICH) guidelines for the identification, control and quantification of residual solvents. This revision, effective July 1, 2007, replaces previous methods that were not consistent with the ICH guidelines. Here we provide an overview, chromatograms, and technical tips for successfully running the new procedure.
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With More Stationary Phase Choices on 1.9µm Pinnacle™ DB HPLC Columns

Ultra-high pressure liquid chromatography (UHPLC) can significantly increase efficiency and produce faster separations. The small particle sizes used in UHPLC improve efficiency; however selectivity is still the most important factor affecting compound resolution. Here we demonstrate the importance of stationary phase choice in UHPLC separations. By optimizing selectivity for your analytes of interest, faster separations can be achieved without compromising resolution.
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Pass System Suitability Requirements with a Smaller Bore Liner

For headspace applications involving a transfer line, a smaller bore liner (preferably 1 mm) can improve system suitability pass rates. This lower liner volume decreases band broadening and allows quicker sample transfer by increasing the linear velocity through the inlet.
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Using a Retention Time Index for Fast and Accurate OVI Separations

To make column selection for residual solvents easy, Restek has benchmarked the ICH Class 1, 2 and 3 residual solvents on our most popular OVI columns.
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Improve Retention by Using an Allure® Biphenyl HPLC Column

Non-steroidal anti-inflammatory drugs (NSAIDs) are typically separated on C18 phases. Separations on our Allure® Biphenyl HPLC column are based on pi-pi interactions, resulting in optimized retention and selectivity. Increased retention requires higher organic content in the mobile phase, increasing desolvation efficiency in LC/MS. Simple mobile phase changes enhance selectivity, making this column a great alternative to conventional phenyl phase columns, especially in method development.
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Optimizing System Suitability, Using an Rxi™-5ms Column

An Rxi™-5ms column and a wool-packed inlet liner provide the stability and inertness needed for these basic, active analytes. Chromatography from a six-replicate system suitability analysis was well within normal acceptance criteria. USP tailing factors were approximately 1.00 for all analytes; retention times and area responses were very stable.
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An Ultra Aqueous C18 Column Provides the BestRetention of Polar and Weakly Polar Compounds

Among hydroxybenzoic acids, hydroxyl groups on the benzene ring vary by position and number, creating differences in overall polarity and solubility. The unique bonding chemistry of the Ultra Aqueous C18 phase assures high resolving power, the best separations across a broad range of analyte polarity, and compatibility with 100% aqueous mobile phases.
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Single-injection, dual-column detection/confirmation assay is feasible for regulated solvents in pharmaceutical products, but no temperature program provides sufficient resolution on both columns. Using a Restek G43/G16 column pair and independent temperature programs in a Gerstel MACH column heating system, we analyzed and confirmed 23 Class 2 solvents in 8 minutes.
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An Allure™ PFP Propyl column exhibits the retention needed to resolve these active, basic compounds, without derivatization or ion-pairing agents. Selectivity can be adjusted simply by changing the organic modifier in the mostly aqueous mobile phase.
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Two Restek columns provide good retention, selectivity, and peak shape for SSRIs, without ion-pairing chromatography. Choose an Allure™ Basix column and neutral pH conditions, or an Ultra PFP column and acidic conditions — either will improve performance for these basic compounds, relative to alkyl phases.
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Overall, three columns provide excellent repeatability in a simple analysis: Allure™ PFP Propyl, Ultra C18, and Allure™ Biphenyl. An Allure™ Biphenyl column employs π-π bonding with the ring structures of the tetracycline molecules to ensure good capacity, high selectivity, and the most symmetric peaks.
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The Allure™ Biphenyl HPLC Column

Relative to phases that separate via hydrophobic or polar interactions, the Allure™ Biphenyl stationary phase offers better retention, selectivity, and efficiency, when analyzing compounds with differences in the numbers and locations of unsaturated bonds in the hydrocarbon ring structure.
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Early detection of structural mold is critically important to protecting human health and property values. Restek SilcoCan™ canisters allow low levels of microbial volatile organic compounds (MVOCs) to be detected in air samples before mold can be seen, providing an opportunity for structural repair and safer living conditions. The inertness of these canisters provides an exceptional storage environment, particularly for polar and high boiling point compounds.
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Restek Sampling Equipment Helps Assure Accurate Data

TO-Can™ air sampling canisters are electropolished and extensively cleaned, to provide a high-quality, passivated surface for improved stability of analytes listed in USEPA Method TO-15 (ambient air monitoring). For reactive compounds, such as sulfur-containing components, SilcoCan™ canisters are your best choice — our exclusive Siltek® surface treatment ensures exceptional inertness and maximum sample stability, even for 1-20ppb sulfur compounds.
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With QuEChERS Products

If you are frustrated by the time and cost involved with pesticide sample cleanup, we suggest you try the simple and economical QuEChERS method. Follow this approach to remove sugars, lipids, organic acids, sterols, proteins, pigments, and excess water, any of which often are present. To make your work even simpler, we offer QuEChERS extraction products in a variety of standard sizes and formats, and custom products by request.
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Using Viva Wide Pore HPLC Columns

Viva Wide Pore HPLC columns are ideal for the separation of large molecules, as target analytes can enter the larger pores and access more of the surface area. Here we demonstrate the added retentive power of these columns, using the PEGylation of oxytocin as an example. Separation of these large, closely related compounds demonstrates the suitability of Viva Wide Pore columns for monitoring PEGylation reactions, and other large molecule applications.
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A Viva C18 wide pore HPLC column resolves a tryptic digest of bovine serum albumin primarily into 1-2 peptide peaks, versus peaks of 3 or more peptides typically provided by conventional C18 columns. This superior resolution helps ensure more reliable identification of peptides in complex mixtures.
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Restek Sampling System Treatments Prevent Adsorption, Protect Components

Siltek®/Sulfinert® surface treatments improve component performance by significantly reducing corrosion and adsorption problems in the sampling and sample transfer pathways. These treatments improve sampling accuracy, increase component lifetime, and cost less than super alloys. Treatments can be applied to cylinders, valves, fittings, tubing and more, and demonstrably improve detection of low-level sulfur, nitric oxide, and mercury compounds in a wide variety of applications and industries.
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Use Siltek® Surface Treatment on Steel Components

As concerns about mercury in the environment grow, new regulations and testing requirements emerge. To ensure accurate results, sample storage and transfer systems must be inert to elemental mercury. Here we demonstrate that Siltek® treatment provides an unreactive surface compared to stainless steel. Data shown demonstrate that Siltek® treatment of sampling systems will improve analytical accuracy. Siltek® treatment is available on many stock items and custom components can be treated upon request.
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Using Hydroguard™ Deactivated/Silcosteel® Treated Tubing

Tubing deactivated with Hydroguard™ and treated with Silcosteel® is preferred for situations in which water vaporization is encountered, such as in purge and trap systems. Hydroguard’s™ unique deactivation chemistry creates an outer surface that prevents water vapor from contacting the Silcosteel® treated stainless steel surface below. This protected inert surface allows active analytes to pass through the tubing without adsorbing to the surface.
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Restek Surface Treatments ImproveSampling and Transfer Component Performance

In sampling or process stream pathways, Siltek®/Sulfinert® treated tubing reduces uptake of active (e.g., sulfur) compounds by orders of magnitude, relative to untreated tubing, for reliable data about stream composition. Silcosteel®-CR treated tubing improves corrosion resistance by up to 10X over untreated tubing, reducing the need for maintenance and helping to ensure the purity of the sample or process stream.
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Treated Fittings and Tubing

Silcosteel®-CR treatment is highly effective protection for stainless steel exposed to hydrochloric acid, nitric acid, or marine environments: in independent tests, Silcosteel®-CR treatment upgraded the corrosion resistance of 300-grade stainless steel by an order of magnitude. Now, electropolished stainless steel tubing and a wide selection of world-renowned Swagelok® fittings are available with Silcosteel®-CR treatment, from stock. Custom treatment of system components also is available.
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Content previously published in Separation Science

Overloading GC columns affects peak symmetry and can cause coelutions and retention time shifts. This article provides tips on diagnosing and correcting overloading problems.
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Content previously published in Separation Science

Many compounds are susceptible to thermal degradation. This article explains how to diagnose and reduce analyte decomposition in both the GC inlet and column.
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Washerless, Leak-Tight Seals for Agilent GCs

Restek’s Dual Vespel® Ring inlet seal gives you a better seal with fewer parts. Data show that the soft Vespel® material has a much lower leak rate than a metal seal. Also, since less torque is required for installation, user variability is reduced.
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The current acetonitrile shortage has labs scrambling to adjust to limited supplies and increased costs. Here we discuss short- and long-term strategies to reduce acetonitrile consumption, including method development based on alternative solvents.
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Scaling down column size is simple to do and can help reduce solvent use. Here is an easy-to-follow example that teaches you how to reduce column internal diameter.
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Reduce System Stress by Backflushing Your HPLC Column

High pump pressures can be caused by heavily retained impurities building up in the head of the analytical column. Such contamination can cause poor chromatography, usually in the form of broad, split, or misshapen peaks, and ultimately can compromise results. Backflushing a contaminated analytical column, using the procedure outlined here, can help restore column performance and reduce pump pressure and system strain.
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Understanding the significant factors that affect HPLC guard column performance can help you protect your analytical column and save money by extending analytical column lifetime. Here we review available options in packings, dimensions, cartridge holders, and filters to help you select the best guard column system for your application.
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How to Correctly Diagnose the Source of Bleed Contamination

Septum bleed is generally attributed to the injection port septum; however, the vial cap septum also can be a source. Bleed contamination from any septum can cause interfering peaks and lead to inaccurate results, so it is important to correctly identify the source and understand how to eliminate or minimize bleed level. Here we discuss how to diagnose the source of the bleed and review considerations that can reduce the amount of contamination.
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Why Conditioning Your Inlet Parts After Maintenance Is Good Practice

Background noise in a gas chromatography system can be eliminated by conditioning the system prior to sample analysis. In this article, we discuss warm-up procedures and use liners and liner installation to demonstrate the importance of conditioning the system to remove background peaks. Investing a little time in warming-up the system pays big dividends by preventing costly coelutions and avoidable reanalyses.
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Switch Your GC Carrier Gas to Hydrogen

Faced with helium shortages and prices that continue to soar upwards like a runaway party balloon? Consider switching to hydrogen as your carrier gas. High-quality hydrogen is readily available from either high-pressure cylinders or hydrogen generators. It is cost-effective and provides shorter analysis times (by half if running isothermally) than helium and many times yields better separations.
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Tips & Techniques for Long-term Instrument Performance

Simple tips and techniques are presented to improve the accuracy and precision of your data by keeping your column oven at peak performance. Details on reducing variation around the oven set point through calibration and maintenance are given.
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Do you need to connect a GC analytical column to a guard column or transfer line? Or repair a broken column? How about connecting two columns for primary and confirmation analysis from a single injection? Restek’s extensive selection of GC connectors makes all of these connections possible. Here we review differences among our connectors and answer some frequently asked questions about our popular Press-Tight® connectors.
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Most HPLC methods can be coupled with mass spectral detection provided appropriate attention is given to pump capabilities, column diameter, and system plumbing, and to sample matrix and mobile phase composition. Here we discuss these considerations and provide tips on adapting your method to include mass spectral detection using either electrospray ionization or atmospheric pressure chemical ionization.
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Micropacked columns are 1-2 meter, 0.75-1.0mm ID packed stainless steel columns with performance characteristics intermediate between conventional packed columns and capillary columns. They are inexpensive, very durable, and easy to install and operate. They have a wide range of applications, but are especially useful for analyses of gas mixes, including sulfur compounds or light hydrocarbons, for which a packed column is needed to obtain baseline separations of sample components.
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Real People, Real Time and Real Results for YOU!

Restek’s Technical Support group includes more than 64 individuals with extensive experience in chemistry, chromatography, engineering, and related fields. When you call Restek, you have access to the combined expertise of everyone in this group. With more than 110 international distributors and dealers in 81 countries, we can understand and respond to your lab’s unique challenges whether you are in North America, South America, Africa, Asia, Europe, the Pacific Rim or elsewhere.
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The Restek Chromatography Information Services Group answers hundreds of questions each month. The answers provided here deal with inquiries about guard column chemistry, column temperature limits, ghost peaks in GC/MS analyses, pesticides breakdown on cyano-phase columns, and column cage options.
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Proper conditioning is essential for optimal performance from a capillary GC column, but inexperienced chromatographers might not know the proper procedures for installing and conditioning a new column. Here, we summarize our recommendations for installation and conditioning procedures.
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Analysts should use an electronic leak detector when installing a new column or fitting, changing a cylinder, or troubleshooting the system. The portable, reliable, easy-to-use Restek Electronic Leak Detector reveals minute leaks without contaminating the system.
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Handy tips and tools for choosing the right septum for your application and instrument. Includes an overview of common septum problems including coring and bleed. Guidelines help you avoid extraneous peaks and optimize your system’s performance.
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Inlet design, including placement of the heating element, differs among manufacturers and as a result the temperature at the septum differs from the actual set point and the degree of this difference varies among manufacturers. Septa brands, however, are given a single maximum operating temperature. Here we demonstrate the temperature gradients within inlets for several popular GC models and discuss the pros and cons of hotter and cooler inlets.
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EZ Twist Top™ Split/Splitless Port for Agilent GCs

Using our unique EZ Twist Top™ Injection Port, Septum Nut Removal Tool, and Inlet Liner Removal Tool, you can reduce maintenance time and frustration, eliminate tangled gas lines that can lead to leaks, and avoid contact with hot surfaces. The gas lines are attached to the EZ Twist Top™ Shell Weldment, not to the weldment — they are under the GC cover and cannot interfere with routine injection port maintenance. Changing inlet liners becomes a quick and simple task.
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Regular injection port maintenance helps ensure the best results from your analyses, and helps minimize downtime. Each FastPack™ inlet kit includes all the parts you need to perform routine maintenance — inlet liner (choose from four styles), O-ring, inlet seal and inlet seal washer, and septum — in a sealed Mylar® bag.
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