Influences of seven Taiwan-produced adulterants on gas chromatographic-mass spectrometric (GC-MS) urinalysis of amphetamines

This study was conducted to better understand the influences exerted by seven Taiwan-produced adulterants on the forensic gas chromatographic-mass spectrometric (GC-MS) confirmatory urinalysis of amphetamines. The results verified that, when added at 5-15% (w/w), chlorine bleach would lower the GC-MS outcomes of the spiked and case specimens by 36-63%, and was most likely to cause false negatives. Liquid soap, potassium dichromate, soda water for drinking, and tap water would decrease the GC-MS outcomes by 9-29%, 8-20%, 8-20%, and 5-16%, respectively, and also had the risk of negating near-cutoff initial positives into false confirmatory negatives. The negative-directing effects were mostly due to degradation of analytes and/or deactivation of the derivatizing agent by oxidizing adulterants and/or dilution of analytes by the added liquid. Alum and table salt added as powder had little impact on the test. Responsible institutions and relevant laboratories should face the facts seriously and include the specimen validity testing (SVT) battery in the routine drug testing procedures.