Development and validation of a simple chromatographic method to screen oral fluid samples for drugs in DUID investigations.

A simple and rapid qualitative chromatographic method with a unique extraction approach was developed and validated to screen oral fluid samples for 31 compounds in driving under the influence of drugs investigations. The scope and sensitivity of the method meets or exceeds Tier I recommendations established by the National Safety Council's Alcohol, Drugs and Impairment Division. Since this is a targeted chromatographic screen (rather than an immunoassay), cutoffs were set to match the confirmation levels in the recommendations. Sample preparation involved a single-step liquid-liquid extraction procedure, using a mixture of methyl tert-butyl ether, isopropanol, and hexane and was applied to samples collected with the QuantisalTM device. Instrument analysis was conducted by liquid chromatography-tandem mass spectrometry, using a Restek RaptorTM biphenyl column for chromatographic separations and a total run time of 8 min. Validation results met all requirements of ANSI/ASB Standard 036 (1st edition)-Standard Practices for Method Validation in Forensic Toxicology.

ELISA Screens for Fentanyl in Urine Are Susceptible to False-Positives in High Concentration Methamphetamine Samples.

Immunoassay techniques are commonly used for urine drug screening in forensic and clinical toxicology laboratories. While these techniques are excellent for the nonspecific detection of a wide variety of drug classes, their very nature renders them vulnerable to false negatives and false positives.The New York State Police Forensic Toxicology Laboratory investigated a trend of false-positive fentanyl urine drug screens and determined that urine methamphetamine levels greater than 40 µg/mL can cause a false-positive urine fentanyl screening result using the Neogen enzyme-linked immunosorbent assay kit at a 1 ng/mL fentanyl decision point.

Demoxepam Derivatization and GC-MS Analysis Produces Erroneous Nordiazepam and Oxazepam Results.

Demoxepam, when derivatized by silylation and analyzed using gas chromatography-mass spectrometry (GC-MS), produces artifacts which are falsely identified as nordiazepam and oxazepam. Demoxepam was analyzed unextracted at various concentrations, using different derivatization procedures, and on different GC-MS systems. Oxazepam and nordiazepam were consistently identified in neat demoxepam samples, despite the changing variables. Under certain conditions, oxazepam was identified as low as 50 ng/mL derivatized demoxepam, and nordiazepam identified as low as 500 ng/mL derivatized demoxepam. The analysis of underivatized demoxepam resulted in nordiazepam detection at levels ≥2,500 ng/mL, whereas oxazepam was not detectable at or below 10,000 ng/mL demoxepam. Isolating the derivatization procedures and GC-MS analyses demonstrates that these processes are responsible for any degradation or rearrangement reactions which are taking place. Laboratories which follow similar procedures for benzodiazepine confirmations should consider these findings when interpreting analytical data from chlordiazepoxide cases.