Restek at MSACL 2023


2-7 April, Monterey, CA, U.S.

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Live Demonstrations: Booth 20 

Pro EZLC Chromatogram Modeler Software 

See how to create LC methods in minutes with free, easy-to-use Pro EZLC chromatogram modeling software.

  • Tuesday: 8:00 p.m.
  • Wednesday: 2:00 p.m.
  • Thursday: 11:00 a.m.

Poster Presentation

The Development of a Virtual Liquid Chromatography Method Development Tool

05 April 2023, 11:00 a.m. - 1:00 p.m.

Authors: Melinda Urich , Justin Steimling, Jamie York, Chris Nelson, Tim Yosca, John Garrett

Presenters: Melinda Urich

The development and optimization of liquid chromatography (LC) separations can be time consuming and costly, often requiring a number of steps including literature research, column selection, method scouting, method development, and method optimization. In an effort to eliminate these steps, an instrument-free, software modeling tool that gives users the ability to select compounds from a database and instantly model a separation on different column phases was developed.
Optimization of the model can be performed while maintaining critical pair separations by adjusting for instrument/system effects (e.g., dwell volume and extra column volume), mobile phase preferences, number of gradient steps, and more. The initial database consists of a Drugs of Abuse (DoA) library containing approximately 250 compounds with plans to continually expand the utility.
A modeled chromatogram and instrument-ready conditions are automatically generated and can be further optimized by users. During software development, the acceptance criteria for retention time agreement between wet-lab and modeled values was set at +/- 15 seconds. This range was chosen because it represents a typical MRM window. In the most complex portion of the verification, 704 retention time data points were collected in total for the 25 compounds used in the evaluation. Only 13 data points exceeded the+/- 15 second window with no compounds missing acceptance criteria by more than five seconds, giving an overall pass rate of 98.2%.
For LC method developers, novices, and experts who either lack the expertise, or the time, to develop separations quickly and accurately, this free tool can be used to deliver a fast, no-cost starting point for method development and optimization. This novel, virtual method development software can improve turnaround time, increase throughput to existing methods, and offer an on-demand consultative user experience.

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The Study of Three HPLC Column Chemistries for Optimal Separation of THC Isomers

05 April 2023, 11:00 a.m. - 1:00 p.m.

Authors: Haley Berkland

Presenters: Haley Berkland

The emergence of Δ9-tetrahydrocannabinol (Δ9-THC) isomers, particularly Δ8-tetrahydrocannabinol (Δ8-THC), have created analytical challenges. Traditional methods for separating Δ8-THC and Δ9-THC do not adequately resolve these metabolites, resulting in quantitation issues and the inability to determine an accurate value for one or both isomers. This issue is especially prevalent in urine samples where these metabolites may be detected at high concentrations.
The primary objective of this study was to evaluate the capability of different HPLC column chemistries to separate Δ8-THCCOOH and Δ9-THCCOOH.
Multiple LC-MS/MS methods were developed and optimized to separate Δ8-THCCOOH and Δ9-THCCOOH using a Raptor Biphenyl (2.7 μm, 100 x 2.1 mm), Raptor C18 (2.7 μm, 100 x 2.1mm), and a Raptor FluoroPhenyl (2.7 μm, 100 x 2.1 mm). Each method used water and methanol as MPA and MPB respectively, both acidified with 0.1% formic acid.
Of the three stationary phases tested, the Raptor FluoroPhenyl column chemistry provided optimal separation of Δ8-THCCOOH and Δ9-THCCOOH in the shortest analysis time. The separation completely resolved the isomers, preventing quantitation errors caused by the analytes interfering with each other.

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Simultaneous Analysis of Methionine Pathway Metabolites and Methylmalonic Acid

05 April 2023, 12:30 p.m. - 2:00 p.m.

Authors: Samantha Herbick, Justin Steimling

Presenters: Samantha Herbick

Metabolites in the methionine pathway, as well as methylmalonic acid (MMA), are important biomarkers in the diagnosis of certain cobalamin disorders. Raised plasma levels of methylmalonic acid, methionine, or total plasma homocysteine can be indicative of these disorders, and, therefore, the chromatographic separation of isomers and quantitation of these analytes is needed in diagnosing these different disorders.
A rapid four-minute LC-MS/MS method was developed for the simultaneous analysis of methionine pathway metabolites, including homocysteine, methionine, cysteine, and cystathionine, as well as methylmalonic acid and succinic acid in plasma. Complete chromatographic separation of all compounds was achieved using a Raptor Polar X column under HILIC conditions. The method employed a simple sample reduction procedure using DTT, replacing time-consuming derivatization procedures. Reproducible retention times and selectivity were demonstrated throughout testing. Acceptable precision and accuracy results for the quantitative analysis of total plasma homocysteine and methylmalonic acid, as well as accuracy of the surrogate matrix by the used of standard addition testing, were also achieved.

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