MSACL 2016 US Abstract

A Multi-Class Drug and Metabolite Screen of 231 Analytes by LC-MS/MS

Shane Stevens (Presenter)
Restek Corporation

Authorship: Shane Stevens, Frances Carroll, Sharon Lupo, Shun-Hsin Liang, Ty Kahler, Paul Connolly
Restek Corporation, 110 Benner Circle Bellefonte, PA 16823

Short Abstract Therapeutic drug monitoring can be challenging due to the low cut-off levels, potential matrix interferences and isobaric drug compounds. To address these challenges, many drug testing facilities are turning to liquid chromatography coupled with mass spectrometry (LC-MS/MS) for its increased speed, sensitivity, and specificity. The Raptor™ Biphenyl column was developed to complement high-throughput LC-MS/MS analyses by combining the increased efficiency of superficially porous particles with the resolution of Ultra Selective Liquid Chromatography™ column technology. In this example, a method was developed for a 231 compound multi-class drug and metabolite screen.

Long Abstract

The use of pain management drugs has been steadily increasing. As a result, hospital and reference labs are seeing an increase in patient samples that must be screened for a wide variety of drugs to prevent drug abuse and to ensure patient safety and adherence to their medication regiment. Therapeutic drug monitoring can be challenging due to the low cut-off levels, potential matrix interferences and isobaric drug compounds. To address these challenges, many drug testing facilities are turning to liquid chromatography coupled with mass spectrometry (LC-MS/MS) for its increased speed, sensitivity, and specificity. The Raptor™ Biphenyl column was developed to complement high-throughput LC-MS/MS analyses by combining the increased efficiency of superficially porous particles with the resolution of Ultra Selective Liquid Chromatography™ column technology. In this example, a method was developed for a 231 compound multi-class drug and metabolite screen.

There are many challenges one must consider when developing a large screening assay. Experiments performed included mobile phase considerations, sample diluent, isomer resolution, drug interferences, and instrumentation capabilities. Analytes were diluted in water and injected into a Shimadzu Nexera UHPLC equipped with an AB SCIEX API 4500™ MS/MS. Detection was performed using electrospray ionization in positive and negative ion modes using scheduled multiple reaction monitoring (MRM).

During mobile phase investigations, it was found that methanol provided the best retention of early eluting analytes, such as morphine, oxymorphone, nicotine and norcotinine. Sample diluent was optimized to improve the peak shape of the early eluting compounds. Scan rates and retention time windows were optimized to insure enough data points per peak were collected.

The final optimized separation was performed using water and methanol mobile phases modified with 0.1% formic acid and 2 mM Ammonium formate under gradient conditions on a Restek Raptor™ Biphenyl 2.7µm, 100 x 2.1mm column equipped with a Raptor™ Biphenyl EXP® 2.7µm, 5 x 2.1mm guard column. The gradient run time was 10 minutes, with a total cycle time of 12 minutes. Of the mixture of analytes, 209 were analyzed in positive ion mode, and 22 were analyzed in negative ion mode.

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