AI-64310-CRFT

MS/MS as an LC Detector for the Screening of

Drugs and Their Metabolites in Race Horse Urine

Gargi Choudhary and Diane Cho, Thermo Fisher Scientific, San Jose, CA

Wayne Skinner and Scott Stanley, University of California–Davis

Application

Note: 346

Key Words

• LCQ Advantage

MAX

™

• Surveyor

™

• Data Dependent

™

• Drug Screening

• Metabolite ID

• Toxicology

Introduction

Imipramine is a tricyclic antidepressant drug that is not

a Drug Enforcement Administration controlled substance

but has been classified by the Association of Racing

Commissioners International Inc. as a class two drug in

horses. Desipramine is a major metabolite of imipramine.

These two analytes were analyzed on-line by LC–PDA

MS/MS from extracts of horse urine. The urine sample

was first treated with -glucuronidase to hydrolyze

glucuronide conjugates of imipramine and desipramine.

This was followed by solid phase extraction. The

concentration of imipramine and desipramine in the

sample was determined by the internal standard method

using the peak area ratio and linear regression analysis.

This application note presents a rapid method for

quantitation of imipramine and desipramine in horse

urine. It illustrates the advantages of MS/MS detection

in terms of specificity, sensitivity and unambiguous identi-

fication, for the analysis of drugs and their metabolites.

Goal

1) Develop a rapid method to identify and quantitate

tricyclic antidepressant imipramine and its major

metabolite desipramine in horse urine.

2) Demonstrate the advantages of using MS/MS to

identify and confirm the detection of imipramine

and its metabolites.

3) Determine presence and structure of minor metabolites

using Data Dependent LC-MS/MS analysis.

Experimental Conditions HPLC

LC system:

Thermo Scientific Surveyor MS Pump,

Surveyor Autosampler and Surveyor PDA

Detector

Mobile phase: A: water containing 0.2% formic acid

B: Acetonitrile containing 0.2% formic acid

Column:

2.1 mm, 5 µm Thermo Scientific

Hypersil

™

C18 Column

Injection

volume:

1 µL

Flow rate:

200 µL/min

Gradient:

Time (min)

% A

0.2

10.01

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