Restek Talks
Restek Posters
Restek Event Information




RESTEK TECHNICAL PRESENTATIONS



 

Special Event:


2:00 p.m. Mon.–Wed. at Booth 4520
New Pro EZGC Chromatogram Modeler Demonstration
Join us at the Restek booth (4520) for a demonstration of our new EZGC chromatogram modeler. This powerful tool has been updated and now offers advanced controls and more optimization capabilities. We’ll provide a live demonstration daily at 2:00 p.m., but you can stop by anytime to try it yourself!

Short Courses:


Monday, March 6, 1:00 p.m.–5:00 p.m.
(34) Injection Techniques in Gas Chromatography
JAAP DE ZEEUW, Restek
For more information, e-mail Jaap de Zeeuw.
Read abstract

Course description
In gas chromatography (GC), the most important process is to get the sample into the column. If sample transfer is not optimized, the results will not be reliable. The goal of this course is to understand different injection techniques and how to obtain a narrow injection band.

Outline
In this half-day course, we will discuss the basics of the most popular injection techniques that are used in GC. Techniques like split, splitless, direct, on-column, and large volume injection will be discussed in detail. Also, we will address how to select liners, retention gaps, and columns. All techniques will be explained using practical examples. At the end, we will zoom in on some typical "injection" troubleshooting examples.

Target audience
This short course is intended for users of GC equipment who want to understand how different injection processes work. You will be able to choose between techniques and understand the most important maintenance and troubleshooting items for GC application work. For best results, some experience with GC separations and analytical chemistry is preferred.


Restek on FacebookRestek on TwitterRestek on LinkedInImage HTML map generator

Tuesday, March 7, 8:30 a.m.–12:30 p.m.
(39) Practical Maintenance and Troubleshooting in Gas Chromatography
JAAP DE ZEEUW, Restek
For more information, e-mail Jaap de Zeeuw.
Read abstract

Course description
In GC, 90% of the trouble experienced happens in the injection system. In this course, we will discuss the purpose and impact of the critical parts (consumables) present in split and splitless injection and how they affect a maintenance schedule. At the end, we will discuss a series of practical examples via troubleshooting exercises.

Outline
In this half-day course, we will discuss maintenance challenges for split and splitless GC injection techniques. We will discuss, in detail, topics including carrier gas choice and purity, tubing, connections, septa, ferrules, seals, liners, column coupling, installation, and column maintenance. We will also explore column operation/optimization and how to extend column lifetime.

Target audience
This short course is intended for the practical user of GC equipment who wants to understand the most important maintenance and troubleshooting items for GC application work. For best results, some experience with GC separations and analytical chemistry is preferred.


Oral Sessions


Sunday, March 5
Session 180, Room W177, 3:25 p.m.
(200-6) Using Free, High-Performance, Computer Modeling Software to Simulate Gas Chromatographic Separations
JAAP DE ZEEUW, Restek
Rebecca Stevens, Kristi Sellers, Scott Adams
For more information, e-mail Jaap de Zeeuw.
Download a PDF of the full presentation.
Read abstract

Pro EZGC is a recently developed, free-to-use, web-based computer program has been employed to accelerate GC method development by direct simulation of the chromatographic process. The program makes use of a highly accurate time-summation modeling approach, coupled with large libraries of data to provide absolute retention time predictions within 1% of those obtained from experiment.

The user is able to directly control every parameter of the chromatography being modeled including carrier gas, stationary phase, column dimensions, and temperature program. The temperature program can be iteratively optimized to obtain the desired separation in the minimum run time. The software is preloaded for modeling of more than 20 different stationary phases and hundreds of compounds including pesticides, PCBs, PAHs, semivolatiles, and volatile organics.

GC modeling features will be discussed with a focus on experimental agreement for both atmospheric and vacuum outlet GC. Modeling in the context of method development and modeling of very challenging separation problems will be included. Our goal is to make computer modeling of GC separations an intuitive and easily accessible tool in laboratory workflows.


Monday, March 6
Session 450, Room W475B, 10:45 a.m.
(450-7) Application of Personal Air Sampler
JASON HERRINGTON, Restek
Jaap de Zeeuw, Rebecca Stevens, Gary Stidsen, Steve Kozel
For more information, e-mail Jason Herrington.
Download a PDF of the full presentation.
Read abstract

The Aura personal air sampler (PAS) passively collects an 8-hour, whole-air sample via vacuum in a 400 mL canister. The sampler was developed to help environmental and occupational health experts monitor for personal exposures to airborne volatile organic compounds (VOCs). The Aura PAS was designed as an alternative to diffusive sampling badges and/or active sampling with thermal desorption (TD) tubes, and it was engineered to avoid some of the shortcomings associated with these approaches. A field study applying the Aura PAS and the most popular competing technologies has been executed. The current presentation will discuss the results and implications of this study.


Session 460, Room W476, 9:10 a.m.
(460-3) Evaluation and Application of SPME Arrows
JASON HERRINGTON, Restek
Jaap de Zeeuw, Rebecca Stevens, Gary Stidsen, Steve Kozel
For more information, e-mail Jason Herrington.
Download a PDF of the full presentation.
Read abstract

Solid phase microextraction (SPME) fibers were developed and patented by Janusz Pawliszyn in 1990 and were subsequently licensed to Supelco until 2014. However, SPME technology has largely remained unchanged over the last 26 years and is subject to the following significant drawbacks: limited mechanical stability and small phase volumes. The PAL SPME Arrow was developed to overcome the aforementioned shortcomings. SPME Arrows have an outer diameter of 1.1 or 1.5 mm. Compared to traditional SPME fiber diameters of ~0.5 mm, SPME Arrows have larger sorption phase surfaces (up to 6x) and volumes (up to 20x). In addition, the arrow-shaped tip facilitates smooth penetration of vial and injector septa, and the Arrow design fully protects the sorptive material, thereby minimizing adverse influences and the loss of analytes during the transfer processes. The following presentation will provide an evaluation of PAL SPME Arrows and a side-by-side comparison with traditional SPME fibers. An application to Method 8260B, which capitalizes on the claimed advantages of SPME Arrows, will be presented as well.


Thursday, March 9
Symposium Session 2140, Analytical Cannabis I, Room W183A, 10:35 a.m.
(2140-4) Pesticide Residue Analysis in Cannabis Using Modified QuEChERS and LC-MS/MS
JULIE KOWALSKI, Restek
Jeff Dahl (Shimadzu Scientific Instruments), Derek Laine (Trace Analytics), Jack Cochran (VUV Analytics)
For more information, e-mail Julie Kowalski.
Download a PDF of the full presentation.
Read abstract

The legal cannabis industry is exploding as more states adopt medical and recreational use laws. Cannabis is still federally illegal, so the legal cannabis market is managed by local and state governments. While systems for the growing, production, and sale of cannabis and cannabis-related products are well established, regulation and enforcement of quality and safety testing have lagged behind. State governments and private labs are now starting to focus on product safety testing with special emphasis on pesticide analysis. This is the result of various product recalls, media attention, and concern from patient advocacy groups.

We developed a modified QuEChERS LC-MS/MS method for analysis of multiresidue pesticides. The AOAC QuEChERS method was used for a reduced 1.5 g amount of plant material and processed with universal dSPE. LC-MS/MS analysis used constant polarity switching ESI and monitored at least two transitions per analyte. Matrix-matched calibration was used for quantitation and both method and instrument internal standards were used. Analyte recovery validation was performed according to FDA guidelines by testing three matrices at three fortification levels in triplicate for over 200 pesticides. For the large majority of pesticides, in all three matrices and at all three fortification levels, recovery was between 70-120%.


 

Posters


Monday, March 6
Session 490, Exposition Floor, Aisle 2500-2600
(Poster mounted from 10:00 a.m.–4:00 p.m. Authors present from 10:00 a.m.–12:00 p.m.)
(490-5P) New Diatomaceous Earth Materials for Packed Columns — Exploring Inertness of Solid Support and Effect of
Particle Size (Mesh) and Packed Column ID on Column Efficiency

KRISTI SELLERS, Restek
Jaap de Zeeuw, Rebecca Stevens, Barry Burger, Scott Adams, Katarina Oden
For more information, e-mail Kristi Sellers.
Download a PDF of the full presentation.
Read abstract

Particle size can play an important role when selecting solid support material. Not only do smaller particle sizes have higher peak efficiencies and thus plate height (H) is reduced, but the optimum linear velocity window at which the minimum plate height is achieved is also increased. This presentation will compare chromatographic performance of three different mesh sizes using DiatoSorb-W, a new source of diatomaceous earth (DE). Columns packed with mesh sizes of 60/80, 80/100, and 100/120 will be compared using van Deemter plots and normalized efficiency using HETP (height equivalent to a theoretical plate) as a function of mobile phase linear velocity (pressure on column needed to achieve the required flow). Inertness of the material compared to current DE solid support will also be presented.

Tuesday, March 7
Session 1120, Exposition Floor, Aisle 2500-2600
(Poster mounted from 10:00 a.m.–4:00 p.m. Authors present from 10:00 a.m.–12:00 p.m.)
(1120-11P) Critical Fractionation and Analysis of Water and Soil Matrices Using Tuned EPH Specific Silica Gel Cartridges
KRISTI SELLERS, Restek
Jason Thomas, Alexandria Pavkovich
For more information, e-mail Kristi Sellers.
Download a PDF of the full presentation.
Read abstract

Concern for the environmental and health effects from exposure to materials from leaking underground storage tanks has led to the development of analytical and sample preparation techniques by several states to address specific needs from their own geographical areas. One of the earliest of these was devised by the Massachusetts Department of Environmental Protection. This method is intended for either qualitative identification of total petroleum hydrocarbons (TPH) or for fractionation, detailed analysis, and quantification of both aliphatic and aromatic fractions from site samples of water or soil/sediment matrices [1].

This state method, as well as other similar state methods, presents difficult challenges to laboratories that need to accurately implement techniques employed by the method to effect desirable results, and the fractionation of the aliphatic and aromatic components is particularly difficult. The 5 gram silica gel cartridge specified in the methods needs to be of high quality and consistency in order to achieve adequate separation of the two fractions with minimal interferences.

This work presents a look at the performance of a newly tuned, EPH-specific silica gel cartridge used to carry out this critical fractionation step required in these EPH-specific methods. Several key attributes, such as minimal background extractables, maximum resolving power of aliphatic from aromatic components, and consistent moisture control will be evaluated for their effects on performance.

[1] Massachusetts Department of Environmental Protection, Division of Environmental Analysis, Office of Research and Standards, Bureau of Waste Site Cleanup, Method for the Determination of Extractable Petroleum Hydrocarbons (EPH) Revision 1.1, May 2004.

Session 1430 Exposition Floor, Aisle 2500-2600
(Poster mounted from 10:00 a.m.–4:00 p.m. Authors present from 1:00 p.m.–3:00 p.m.)
(1430-12P) Applying High Speed Gas Chromatography for the Speciation of Fats in Foods and Edible Oils
JAAP DE ZEEUW, Restek
Rebecca Stevens, Jason Herrington
For more information, e-mail Jaap De Zeeuw.
Download a PDF of the full presentation.
Read abstract

Determination of total fat content and its speciation as saturated, unsaturated, polyunsaturated, and trans fat for nutritional labeling is primarily accomplished by derivatization of the hydrolyzed free fatty acids as methyl esters (FAMEs) followed by high-resolution GC-FID analysis. In particular, AOAC method 996.06 describes sample preparation procedures and a GC-FID method for speciation of fats in a variety of food products. Due to the high complexity and very small structural differences among analytes in a typical FAME sample, the preferred GC columns are 100 m or longer and use a highly polar cyanopropyl stationary phase. As a result, the associated GC methods are quite slow; AOAC 996.06 requires over an hour of GC run time per sample not including oven cool down.

The analysis of FAMEs has become increasingly important to food science in recent years. Unsaturated and polyunsaturated fat content is perceived favorably by consumers who, as a whole, are rapidly becoming more conscious of nutritional value. At the same time, the U.S. FDA has issued a final determination that partially hydrogenated oils (those that commonly contain trans fats) are not GRAS and thus cannot be used in food products without specific approval. Fatty acid profiles are also useful in determining origin, authenticity, and sensory attributes of edible oils by chemical fingerprinting.

This work explores using shortened narrow bore columns, high carrier gas flows, and fast oven temperature programming as routes to reducing GC run times for FAMEs analysis. The tradeoff between separation performance and analysis time is explored with the conclusion that relatively complex mixtures of FAMEs can be separated with greatly reduced analysis time.


Wednesday, March 8
Session 1750, Exposition Floor, Aisle 2500-2600
(Poster mounted from 10 a.m.–4 p.m. Authors present from 10:00 a.m.–12:00 p.m.)
(1750-6P) A Simple Solution for Permanent Gas Analysis by Gas Chromatography Using a Dual Column System and
FID/Methanizer Detection

JAAP DE ZEEUW, Restek
Katarina Oden, Mark Badger, Barry Burger, Rebecca Stevens
For more information, e-mail Jaap De Zeeuw.
Download a PDF of the full presentation.
Read abstract

Permanent gas analysis is routinely performed in a variety of industries including petrochemical. In petroleum applications, standard analyses consist of a complex system of packed columns and numerous valve-switching, timed events. In this presentation, we will illustrate a simple solution for the analysis of permanent gases using a dual-column system utilizing TCD and FID/methanizer detection. The methanizer consists of a Ni-catalyst in a heated chamber that in the presence of hydrogen converts CO and/or CO2 into methane, an FID-detectable gas. It is a modern, user friendly, and accurately controlled device that can be easily integrated into any existing GC-FID system. Examples of analytical solutions, robustness of the unit, limits of detection, and system performance will be highlighted.


Session 2070, Exposition Floor, Aisle 2500-2600
(Poster mounted from 10:00 a.m.–4:00 p.m. Authors present from 1:00 p.m.–3:00 p.m.)
(2070-1P) Evaluating Mass Overload on Superficially Porous Particles
PAUL CONNOLLY, Restek
Ed Franklin, Justin Steimling, Ty Kahler, Becky Wittrig, Hansjorg Majer, Susan Steinike, Rob Freeman
For more information, e-mail Paul Connolly.
Download a PDF of the full presentation.
Read abstract

Introduction
Superficially porous particles (SPP) are a powerful analytical tool for achieving fast LC analyses. The solid, impermeable core present in these particles increases the column efficiency by decreasing the diffusion path. However, the solid core also significantly reduces the surface area that is typically available in traditional fully porous particles (FPP). There is a potential concern that arises from a reduction in surface area:column loading ability. Column overloading (mass overload) occurs when the amount of material injected onto the column exceeds the available active sites of the stationary phase. The purpose of this study was to evaluate a series of analytes and to determine the effects the solid core has on the loading ability of superficially porous particles.

Methods
Four columns, varying between SPP and FPP and across particle sizes were used to assess mass loading ability. A neutral, an acidic, and a basic analyte were each analyzed under optimized chromatographic conditions and the peak width at half height (w0.5) was monitored for each injection in order to determine when the mass of analyte exceeded the loading capabilities of the column.

Results
The characteristics of the analyte significantly changed the loading ability of a column. Overload on all of the columns tested for both the neutral and acidic analyte occurred between 1 and 10 µg on column, while the basic analyte began to show overloaded conditions with as little as 0.01 µg on column. There is clearly a trend between the loading ability of the column and the superficial and fully porous particles; however, the trend does not appear to be related to particle volume alone.

Potentially, the most noteworthy conclusion of this study is that the inherent efficiency of particles that are smaller and/or superficially porous makes the effect of overload conditions more pronounced. On a larger particle (i.e., a less efficient column), the initial w0.5 is substantially larger, and an observed peak broadens to the point where the initial overload contribution is no longer distinguishable from the non-overload contribution. In contrast, the peak shape of a more efficient column cannot quickly recover from the initial overload, which may result in the traditional peak shape often associated with mass overload.

Novel Aspect
Study of mass overload on superficially and fully porous particles across multiple particle sizes and analyte types.


Session 2070, Exposition Floor, Aisle 2500-2600
(Poster mounted from 10:00 a.m.–4:00 p.m. Authors present from 1:00 p.m.–3:00 p.m.)
(2070-5P) A Rugged C18 Stationary Phase for Accelerated Analysis
CARRIE SPROUT, Restek
Paul Connolly, Ty Kahler, Frances Carroll, Sharon Lupo, Shun-Hsin Liang, Rob Freeman, Susan Steinike, Rick Lake
For more information, e-mail Carrie Sprout.
Download a PDF of the full presentation.
Read abstract

Fast analysis used to be limited to chromatographers with access to expensive UHPLC systems. The reintroduction of superficially porous particle (SPP) liquid chromatography columns to the marketplace has given everyone access to the increased efficiency and peak capacity to decrease their analysis times. The high amount of hydrophobic retention of a traditional C18 phase is well established and every chromatographer includes one in their cache. This new SPP C18 is an end-capped octadecylsilane phase for fast, rugged, consistent, and reliable reversed-phase chromatography. The particles provide higher efficiency for faster analysis and increased sample throughput on typical LC systems. With them we achieve UHPLC-like speed and performance with a 2.7 µm SPP column and higher efficiency per unit backpressure than traditional fully porous silica supports with a 5 µm SPP column. The versatility of these columns makes them ideal for separations in bioanalytical, CMC testing, food safety, environmental, and other testing areas. Example separations on these particles will be shown to illustrate their contributions to efficiency and overall sample throughput.


Session 2070, Exposition Floor, Aisle 2500-2600
(Poster mounted from 10:00 a.m.–4:00 p.m. Authors present from 1:00 p.m.–3:00 p.m.)
(2070-6P) HILIC, Polar, and Shape Selectivity of a FluoroPhenyl Phase
SUSAN STEINIKE, Restek
Frances Carroll, Shun-Hsin Liang, Sharon Lupo, Ty Kahler, Paul Connolly, Rob Freeman, Becky Wittrig
For more information, e-mail Susan Steinike.
Download a PDF of the full presentation.
Read abstract

The FluoroPhenyl stationary phase has long been marketed as a phase that offers alternative, or orthogonal, selectivity to a C18. The FluoroPhenyl phase offers unique selectivity by incorporating strongly electronegative fluorine atoms on a phenyl ring. In addition to the traditional reversed-phase dispersive interactions, this phase also exhibits shape-selective, polar, cation-exchange, and even HILIC retention mechanisms, which aid in selectivity of specific analytes.

In this presentation, we aim to demonstrate the useful and alternate retention of the FluoroPhenyl stationary phase. We chose several relevant target analytes that we plan to use to exemplify the unique retention characteristics of the FluoroPhenyl phase when used in either HILIC or reversed-phase mode. All of these analytes have been pursued due to either poor retention, poor resolution, or both on a traditional C18 phase.


Session 2070, Exposition Floor, Aisle 2500-2600
(Poster mounted from 10:00 a.m.–4:00 p.m. Authors present from 1:00 p.m.–3:00 p.m.)
(2070-7P) Influencing the Selectivity of Small Proteins and Peptides
KIM SHAFFER, Restek
Sharon Lupo, Shun-Hsin Liang, Frances Carroll, Ty Kahler, Susan Steinike, Paul Connolly, Rick Lake, Rob Freeman
For more information, e-mail Kim Shaffer.
Download a PDF of the full presentation.
Read abstract

Introduction
With the influx of biotherapeutics in medical research and healthcare, the analysis of small proteins and peptides by liquid chromatography (LC) continues to grow. Many of these analyses utilize acid-modified mobile phases to improve peak shape; however, their effects on selectivity and retention are often not well understood. In this presentation, we will explore the effects of acid type, acid concentration, temperature, and gradient slope on the selectivity and retention of several peptide probes using the sterically protected superficially porous Raptor ARC-18 LC column (stable to pH 1).

Methods
Solvent standards containing peptides and small proteins ranging from 238 Da to 12.3 kDa were prepared in acidified water and injected into a Waters ACQUITY UPLC H-Class system configured with a PDA and QDa for simultaneous UV and MS detection. A wavelength of 215 nm and electrospray ionization in positive ion mode were used for UV and MS detection, respectively. Reversed-phase separations were performed using water and acetonitrile mobile phases modified with varying concentrations of either formic acid or trifluoroacetic acid (TFA) under gradient conditions using Restek Raptor ARC-18 LC columns.

Results
Several peptides and small proteins were used as probes to aid in the understanding of selectivity differences that occur when method conditions are manipulated. Through these experiments, it is apparent that the retention of peptides containing basic amino acids (e.g., argentine) exhibit considerably large changes in retention when switching between formic acid and TFA. Variations in acid concentration had a comparable effect. Similarly, changes in elution order were observed in the resulting peptide map following the analysis of a bovine serum albumin (BSA) trypsin digest standard (Protea). Column oven temperature and gradient steepness were shown to impact the band spacing of closely eluting compounds with temperatures ≥ 60 °C and shallower gradients showed the greatest improvement in resolution. For this reason, sterically protected columns that are stable at low pH and high temperatures are often preferred for peptide applications.

Novel Aspect
The effects of acid type, acid concentration, temperature, and gradient slope on peptide selectivity with the sterically protected Raptor ARC-18 column.


Visit the Pittcon website.



EZGC