These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Reanalysis of forensic urine specimens containing benzoylecgonine and THC-COOH.
    Author: Romberg RW, Past MR.
    Journal: J Forensic Sci; 1994 Mar; 39(2):479-85. PubMed ID: 8195759.
    Abstract:
    Drug testing laboratories are often requested to retest specimens that have tested positive. The reproducibility of analytical retest data for delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) and benzoylecgonine in specimens that had previously been analyzed and then frozen by the Navy Drug Screening Laboratory, Great Lakes is examined in this study. All specimens were tested by gas chromatography/mass spectrometry (GC/MS). Retest values generally showed a decrease in concentration but exhibited considerable variability. Eighty-five THC-COOH positive urine specimens stored frozen for 1 to 10 months (average 2.3 months) declined an average of 25% (range, +30% to -80%) and 61 benzoylecgonine positive urine specimens stored for 1 to 8 months (average 2.3 months) declined an average of 19% (ranged +20% to -100%) from initial GC/MS test results. Drugs were found to partition into strata when frozen in urine because of the thermodynamics of the freezing process. To assure a homogenous solution for repeat testing, specimens that have been frozen and thawed were gently mixed before analysis.
    [Abstract] [Full Text] [Related] [New Search]