Interference with analysis of amphetamine in blood by N-ethylbenzenamine from rubber septums.
When blood stored in glass vials sealed with natural rubber septums was screened for amphetamine, a contaminant was seen. The contamination originated from the rubber septums and was identified by GC/MS as N-ethylbenzenamine. Like amphetamine, N-ethylbenzenamine was extracted from strongly alkaline solutions. N-Ethylbenzenamine and amphetamine chromatographed with the same retention time on a packed Apiezon/KOH column and on nonpolar capillary columns. Separation was achieved on a medium polar capillary column. Trifluoroacetyl derivatives of amphetamine and N-ethylbenzenamine had the same retention time on a packed SP-2250 column, but separated on nonpolar capillary columns. The amounts of N-ethylbenzenamine found were high enough to give rise to significant false positive results if N-ethylbenzenamine was erroneously read as amphetamine. N-Ethylbenzenamine is believed to be formed by thermal decomposition of the vulcanizing agent zinc ethylphenyldithiocarbamate used in rubber production.
Christophersen
A S
AS
National Institute of Forensic Toxicology, Oslo, Norway.
Bugge
A
A
Dahlin
E
E
Mørland
J
J
Wethe
G
G
D000661:Amphetamine / Q000097:blood*; D000814:Aniline Compounds / Q000032:analysis*; D001800:Blood Specimen Collection / Q000295:instrumentation; D006801:Humans; D012408:Rubber
D000814:Aniline Compounds; C056400:N-ethylbenzenamine; D012408:Rubber; D000661:Amphetamine