m-Hydroxybenzoylecgonine: an important contributor to the immunoreactivity in assays for benzoylecgonine in meconium.
Meconium has been reported to be a more suitable specimen than maternal or neonatal urine for detecting fetal exposure to cocaine. In a study comparing various immunoassays with gas chromatography/mass spectrometry (GC/MS), several unexplained discrepancies among the assays were noted. Using methanol extracts of meconium samples, an immunoreactive spot that was more polar than benzoylecgonine was detected by thin-layer chromatography (TLC). An extract of this spot analyzed by GC/MS yielded a fragmentation pattern indicative of an aryl hydroxylated benzoylecgonine. Standards of m-hydroxybenzoylecgonine, o-hydroxybenzoylecgonine, and p-hydroxybenzoylecgonine were synthesized; it was determined that m-hydroxybenzoylecgonine had the same retention time and ion ratios as the TLC immunoreactive spot. Furthermore, m-hydroxybenzoylecgonine proved to be immunoreactive. Ten meconium samples immunoreactive for benzoylecgonine were analyzed by GC/MS. Results before and after hydrolysis with beta-glucuronidase (type IX) showed free m-hydroxybenzoylecgonine comprising 59 to 94% of the total m-hydroxybenzoylecgonine and showed total m-hydroxybenzoylecgonine values ranging from 0.2 to 6.3 times as high as benzoylecgonine. Therefore, m-hydroxybenzoylecgonine appears to be a quantitatively important cocaine metabolite in meconium, which is responsible for a significant portion of the discrepancy between benzoylecgonine concentrations in meconium extracts as measured by immunoassay and GC/MS.
Steele
B W
BW
Department of Pathology, University of Miami/Jackson Memorial Medical Center, FL.
Bandstra
E S
ES
Wu
N C
NC
Hime
G W
GW
Hearn
W L
WL
D016477:Artifacts; D003042:Cocaine / Q000031:analogs & derivatives* / Q000032:analysis; D006801:Humans; D007118:Immunoassay; D008470:Meconium / Q000737:chemistry*
C085009:3-hydroxybenzoylecgonine; C005618:benzoylecgonine; D003042:Cocaine