MSACL 2022 Abstract

Consolidating LC-MS/MS Method Conditions for the Analysis of Alcohol Metabolites, Barbiturates, and Drugs of Abuse

Jamie York
Restek Corporation, Bellefonte, PA

Jonathan Edelman (Presenter) Restek

Presenter Bio: Jonathan Edelman began his career as an analytical chemist in the pharmaceutical industry. Inspired by his long-standing love of science and natural ease with sales and marketing, he is currently working to seek strategic business solutions in the chromatography field. Currently, he works for Restek and volunteers his time to a wide variety of nonprofit organizations within the chromatography community. Edelman serves as the treasurer of the ACS SCSC, in addition to serving as Chair of the Organizing Committee for the ISCC/ GCxGC 2021 conference, Executive Committee Person at the Chromatography Forum of Delaware Valley, president emeritus of the Washington Chromatography Forum, and founder and president of the Separation Community Mixer.

Relevant Financial Disclosures (within past 24 months, reported on Mar 12, 2022) No relevant financial relationship(s) to disclose. Conflict mitigation NOT REQUIRED.

INTRODUCTION:
To simplify the analysis of alcohol metabolites, barbiturates, and drugs of abuse in urine, three different methods were developed for each analyte class using the same analytical column and mobile phase compositions. Consolidating LC-MS/MS method conditions allows labs to streamline their analytical testing processes and reduce overall costs.

OBJECTIVES:
The primary objective is to demonstrate the analysis of alcohol metabolites and ESI+/ESI- therapeutic drugs, drugs of abuse, and their metabolites in urine using one set of LC-MS/MS method conditions.

METHODS:
A panel of 136 ESI+/ESI- therapeutic drugs, drugs of abuse, and their metabolites, as well as biomarkers of alcohol consumption, were all analyzed using a Force Biphenyl 50 x 3 mm, 2.7 um analytical column equipped with a Force Biphenyl EXP guard column cartridge and a 0.2 um Ultra Shield frit. Mobile phase A consisted of 0.1% formic acid in water and mobile phase B consisted of 0.1% formic acid in methanol. All methods utilized a column oven temperature of 30 ⁰C. The positive mode isobars utilized gradient conditions with a total cycle time of 10 minutes. Urine samples underwent hydrolysis to convert glucuronide conjugates to their free forms. Barbiturates, THCA-A, and THC-COOH were analyzed in ESI- mode and had a total run time of 5 minutes. These compounds were spiked into urine and diluted at a 1:10 ratio with water. Finally, alcohol metabolites were monitored in ESI- with a total analysis time of 5 minutes. Samples were prepared by diluting with water at a 1:10 ratio and injecting 10 uL.

RESULTS:
The Biphenyl stationary phase has unique selectivity due to the pi-pi interactions that occur between the phase and most drugs and drug metabolites when compared to a routine C18 phase allowing for improved resolution of isobars. A demonstration of the powerful selectivity of this methodology is exemplified for seven isobaric compounds sharing the m/z 286. These compounds include morphine, hydromorphone, norcodeine, norhydrocodone, 7-aminoclonazepam, pentazocine, and asenapine, which are all baseline resolved. Urinary interferences that are particularly problematic in alcohol metabolite testing were resolved without the use of buffer or additional mobile phases helping to streamline analytical testing processes. The ESI- panel that includes barbiturates is able to achieve partial resolution of amobarbital and pentobarbital which allows labs to identify which barbiturate is present in their sample, which may eliminate the need for confirmatory testing.

CONCLUSIONS:
A panel of 136 ESI+/ESI- therapeutic drugs, drugs of abuse, and their metabolites, as well as biomarkers of alcohol consumption, were all analyzed using the same column and mobile phases. This work demonstrates that one LC-MS/MS set up is possible for the analysis of multiple panels. This allows for the user to simplify testing procedures, save time, and ultimately reduce costs.