SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

F17
A MODIFIED METHOD FOR THE LIQUID-LIQUID EXTRACTION AND GCIMS ANALYSIS
OF METHADONE FROM HUMAN URINE IN A CAP-FUDT CERTIFIED DRUG TESTING
LABORATORY
Jeffrey Lavelle, Brian Brunelli, Edward A'Zary*, and Judy Keller. Quest Diagnostics Incorporated,
3175 Presidential Drive, Atlanta, Georgia 30340
In order to produce forensically accurate and reproducible results in a competitive, cost-effective, and time
conserving manner, we took an existing method (1,2) for the extraction of methadone from urine and made
several significant modifications. The internal standard was changed from phenyltoloxamine to methadoned9.
The extraction method was changed from a solid phaselback extraction to a liquid/liquid extraction.
Four organic solvents were tested:
Solvent A comprised of(35:15:40: 1 0) toluene:ethyl acetate:hexane:methanol.
Solvent B comprised of(25:25:50) toluene:ethyl acetate:hexane.
Solvent C comprised of(10:90) toluene:hexane.
Solvent D comprised of (5:95) isoamyl alcohol:hexane.
All solvents were evaluated in a liquid-liquid extraction procedure for quantitation ion areas 72 m/z and}8
mlz with calibrators spiked at 80 nglmL,. 200 ng/mL, and 2000 nglmL. Area recovery studies showed tnat
solvent B was the most desirable of the four extraction solvents. Solvent A was eliminated because it had
the second lowest correlation coefficient (r2 ==0.999985), and because it contained methanol, which could
cause emulsions to form. Solvent C was eliminated because it had the lowest recovery of internal standard
and the largest variation in internal standard recovery. Finally, solvent D was eliminated because it had the
lowest correlation coefficient (r=0.999929) and the second largest variation in internal standard recovery.
Linearity studies with our previous extraction method produced an LOD (Limit of Detection) of 50ng/mL,
LOQ (Limit of Quantitation) of lOOng/mL and an ULOL (Upper Limit of Linearity) of2,OOOnglmL. The
new extraction method allowed this laboratory to expand our ULOL from 2,000ng/mL to 10,OOOnglmL
allowing for an accurate quantitation of high concentrated samples on a first time run without prior dilution.
This method modification reduced the rescheduled rate from 27% to 9%.
1. Clean Screen Basic Drug Procedure, Worldwide Monitoring
2. Taylor, RS,Greutink, C. and Jain, NC "Identification of Underivatized Basic Drugs in Urine by Capillary
Column Gas Chromatography". Journal ofAnalytical Toxicology, 10:205-208 (1986).
Keywords: Methadone, LiquidILiquid, GCIMS
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