Immunoassay and GC-MS procedures for the analysis of drugs of abuse in meconium

Mahmoud A. ElSohly, Donald F. Stanford, Timothy P. Murphy, Barry M. Lester, Linda L. Wright, Vincent L. Smeriglio, Joel Verter, Charles R. Bauer, Seetha Shankaran, Henrietta S. Bada, H. Chip Walls

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

The analysis of meconium specimens for metabolites of substances of abuse is a relatively accurate method for the detection of fetal exposure to drugs. Most of the methods reported in the literature before the early 1990s relied on radioimmunoassays. The purpose of this study was to develop and validate methods for meconium sample preparation for the screening and gas chromatography-mass spectrometry (GC-MS) confirmation of meconium extracts for cannabinoids, cocaine, opiates, amphetamines, and phencyclidine. EMIT(TM) and TDx(TM) immunoassays were evaluated as screening methods. The sample preparation method developed for screening included extraction and purification prior to analysis. Cutoff levels were administratively set at 20 ng/g for 11-nor-Δ9-THC-9-COOH (THCCOOH) and phencyclidine and at 200 ng/g for benzoylecgonine, morphine, and amphetamines, although lower levels could be detected in meconium using the EMIT-ETS(TM) system. Ninety-five meconium specimens were subjected to the screening procedure with GC-MS confirmation of presumptive positives. In addition, 30 (40 for cocaine) meconium specimens were subjected to GC-MS analysis for all analytes regardless of the screening results to determine the false-negative rate, if any, of the immunoassay. Although there were no false negatives detected, the GC-MS confirmation rate for the immunoassay-positive specimens was generally low, ranging from 0% for amphetamines to 75% for opiates. The lowest rate of confirmed positives was found with the cannabinoids, suggesting that tetrahydrocannabinol (THC) metabolites other than free 11-nor-9-carboxy-Δ9-THC may be major contributors to the immunoassay response in meconium.

Original languageEnglish (US)
Pages (from-to)436-445
Number of pages10
JournalJournal of Analytical Toxicology
Volume23
Issue number6
DOIs
StatePublished - Jan 1 1999

ASJC Scopus subject areas

  • Analytical Chemistry
  • Environmental Chemistry
  • Toxicology
  • Health, Toxicology and Mutagenesis
  • Chemical Health and Safety

Fingerprint Dive into the research topics of 'Immunoassay and GC-MS procedures for the analysis of drugs of abuse in meconium'. Together they form a unique fingerprint.

  • Cite this

    ElSohly, M. A., Stanford, D. F., Murphy, T. P., Lester, B. M., Wright, L. L., Smeriglio, V. L., Verter, J., Bauer, C. R., Shankaran, S., Bada, H. S., & Walls, H. C. (1999). Immunoassay and GC-MS procedures for the analysis of drugs of abuse in meconium. Journal of Analytical Toxicology, 23(6), 436-445. https://doi.org/10.1093/jat/23.6.436