Improve Acrylamide Analysis with a Long-Lasting LC Column and a Cost-Effective Internal Standard

Published By: Restek Corporation

Year of Publication: 2019

Link: https://www.restek.com/Technical-Resources/Technical-Library/Foods-Flavors-Fragrances/fff_FFAR3126-UNV

Abstract:The porous graphitized carbon (PGC) columns typically used for acrylamide analysis by method EN 16618.2015 provide adequate retention of acrylamide and sufficient separation from matrix components, but they are subject to short column lifetimes and the need for extensive sample preparation. Here, we demonstrate an approach using an Allure Acrylamide LC column and deuterated internal standard that provides faster total analysis times and meets system suitability requirements longer, allowing labs to significantly increase sample throughput.

A Study of the Re-Equilibration of Hydrophilic Interaction Columns with a Focus on Viability for Use in Two-Dimensional Liquid Chromatography

Author (s) : Claudia Seidl12, David S. Bell3, Dwight R. Stoll1
1. Gustavus Adolphus College,  2. Universidade de São Paulo,  3. Restek Corporation

Published By: Journal of Chromatography A

Year of Publication: 2019

Volume, Issue: Vol. 1604

Link: https://doi.org/10.1016/j.chroma.2019.460484

Abstract:  In recent years there has been increasing interest in the use of HILIC separations in two-dimensional liquid chromatography (2D-LC), mainly because the selectivity of HILIC separations complement that of reversed-phase separations for a variety of molecules. Historically, the re-equilibration of HILIC phases following gradient elution has been perceived as too slow to be useful in the second dimension of 2D-LC separations in particular. Recent studies of re-equilibration of HILIC phases by McCalley and coworkers using a limited set of conditions showed that highly repeatable gradient separations could be obtained with re-equilibration times as short as 4.3 min [1][2]. In this study we aimed to study re-equilibration of HILIC phases under a broader set of conditions, and at much shorter re-equilibration times, in the interest of determining whether or not HILIC separations can be generally considered as a viable option for use in the second dimension of 2D-LC separations. To this end we studied the effects of mobile phase pH, buffer concentration, and preparation method, flow rate, analyte and stationary phase chemistry, column length, and re-equilibration time on retention of a variety of small molecule probe solutes following gradient elution. In general, we have found that excellent separation repeatability can be obtained with quite short (≪10 min) re-equilibration times, even when progress toward full equilibration of the column is quite slow (≫10 min). In other words, even if the stationary phase is not fully equilibrated, as long as it is partially equilibrated in a highly precise manner, highly repeatable retention times can be obtained. Higher flow rate has a positive effect on both the rate of progress toward full equilibration and the repeatability of separation. No significant, consistent effects of eluent pH or buffer concentration on repeatability of gradient separation were observed for the stationary phases studied. Excellent gradient separation repeatability was obtained with shorter columns (30 mm length) with re-equilibration times as short as 3 s. A proof-of-concept 2D-LC separation of several small molecule probes using HILIC separations in both dimensions was performed to illustrate that re-equilibration of these columns can be fast enough for HILIC columns to be considered as a viable option for the second dimension of comprehensive 2D-LC separations.

 

Get More Uptime with Restek’s Long-Life ESI Electrode for Sciex Turbo V Sources

Published By: Restek Corporation

Year of Publication: 2019

Link: https://www.restek.com/Technical-Resources/Technical-Library/General-Interest/general_GNAR3095-UNV

Abstract: The harsh environment inside an MS source takes its toll on ESI electrodes and, once they corrode, sensitivity drops, runs fail, and productivity halts while the instrument is offline for maintenance. The testing detailed here shows that Restek Long-Life ESI electrodes for Sciex Turbo V sources provide equivalent LC-MS/MS performance over significantly longer lifetimes.

Rtx-Wax: A Rugged and Reliable Choice for the Analysis of Glycols in Water

Author: Corby Hilliard and Chris English

Published By: Restek Corporation

Year of Publication: 2019

Link: https://www.restek.com/Technical-Resources/Technical-Library/Environmental/env_EVAR3086-UNV

Abstract: Three types of polyethylene glycol (PEG) columns from different vendors were evaluated to determine which performed best for the analysis of glycols in water. The columns were first challenged with exposure to 600 aqueous injections and then linearity, lifetime, and bleed were assessed. Rtx-Wax columns performed well throughout the test and were the only columns that passed all tests.

 

Using a Methanizer for CO and CO2 Analysis at Low Levels

Author: Mark Badger

Published By: Restek Corporation

Year of Publication: 2019

Link: https://www.restek.com/Technical-Resources/Technical-Library/General-Interest/gen_GNAR3081-UNV

Abstract: Adding a methanizer to a GC-FID is an easy, effective, and cost-efficient way to analyze CO and CO2 at ppb levels. This article explains the technique and shares best practices for preventing problems and obtaining accurate results.

Residual Pesticides Analysis of Botanical Ingredients Using Gas Chromatography Triple Quadrupole Mass Spectrometry

Author(s): Riki Kitano1, Tairo Ogura1, Nicole Lock1, Robert Clifford1, Julie Kowalski2, Jack Cochran2, Dan Li2
1. Shimadzu Scientific Instruments, Inc. 2. Restek Corporation

Published By: Restek Corporation

Year of Publication: 2019

Link: www.restek.com/Technical-Resources/Technical-Library/Foods-Flavors-Fragrances/fff_FSAR3080-UNV

Abstract: Dietary supplements, which are consumed worldwide, are made from various botanical ingredients. To be safe from pesticides exposure, residual pesticides must be monitored by chromatographic instrumentation. Issues arise, however, due to the fact these botanical samples are dried and cause large interferences in the chromatography. This study shows that the modified QuEChERS method combined with GC-MS/MS achieves consistent pesticides monitoring in botanical ingredients.

Acknowledgment(s): Originally published by Shimadzu Corporation in collaboration with Restek Corporation.

Integrating the Analysis of Ultrashort-Chain PFAS: Method Development for Simultaneous Analysis of Ultrashort-Chain, Alternative, and Legacy PFAS

Author: Shun-Hsin Liang and Mike Chang

Published By: Restek Corporation

Year of Publication: 2019

Link: https://www.restek.com/Technical-Resources/Technical-Library/Environmental/env_EVAN3073-UNV

Abstract: A simple direct injection LC-MS/MS method was developed and evaluated for the simultaneous analysis of ultrashort-chain, alternative, and legacy per- and polyfluoroalkyl substances (PFAS) in various water samples. This method is recommended for labs wanting to use a single procedure to analyze compounds from all three PFAS categories in potable and non-potable waters.

PFAS LC Column Anatomy: Which Phase, Dimensions, and Particle Type Are Best?

Published By: Restek Corporation

Year of Publication: 2019

Link: https://www.restek.com/Technical-Resources/Technical-Library/Environmental/env_EVAR3069-UNV

Abstract: With the expansion of PFAS target analyte lists into shorter chain compounds, the need for better methods is growing. But, when developing new analytical procedures, which PFAS LC column is best? This article explores the impact of phase, dimensions, and particle types and provides options that ensure fast, accurate results.

Successful Strategies for the Analysis of EtG and EtS in Urine: Rugged Sample Preparation and Analysis Conditions for High-Throughput Labs

Author: Justin Steimling, Ravali Alagandula, and Frances Carroll

Published By: Restek Corporation

Year of Publication: 2019

Link: https://www.restek.com/Technical-Resources/Technical-Library/Clinical-Forensic-Toxicology/cft_CFAR3061-UNV

Abstract: LC-MS/MS analysis of EtG and EtS is challenging due primarily to poor retention and resolution of EtG and EtS from matrix components. This article presents a foundation method that is useful for many samples and also demonstrates effective strategies for improving sensitivity and mitigating matrix effects.

Rapid, Simple 4.5-Minute Pyrrolizidine Alkaloids Analysis by LC-MS/MS

Published By: Restek Corporation

Year of Publication: 2019

Link: https://www.restek.com/Technical-Resources/Technical-Library/Foods-Flavors-Fragrances/fff_FFSS3064-UNV

Abstract: Pyrrolizidine alkaloid analysis is time consuming, with a typical run time of 15 minutes, and the acid digestion step can shorten analytical column lifetime. In contrast, this analysis using an acid-resistant Raptor ARC-18 column eluted the final compound in just 3.2 minutes with good peak shape and separation.