TY - JOUR
T1 - Rapid biomonitoring of heterocyclic aromatic amines in human urine by tandem solvent solid phase extraction liquid chromatography electrospray ionization mass spectrometry
AU - Holland, Ricky D.
AU - Taylor, Jason
AU - Schoenbachler, Laura
AU - Jones, Richard C.
AU - Freeman, James P.
AU - Miller, Dwight W.
AU - Lake, Brian G.
AU - Gooderham, Nigel J.
AU - Turesky, Robert J.
PY - 2004/8
Y1 - 2004/8
N2 - A rapid and facile tandem solvent solid phase extraction method was established to isolate the heterocyclic aromatic amines (HAAs) 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (8-MeIQx), 2-amino-3,4,8- trimethylimidazo[4,5-f]quinoxaline, 2-amino-1-methyl-6-phenylimidazo-[4,5-b] pyridine, and 2-amino-9H/-pyrido[2,3-b]indole from urine. The HAAs were separated by reversed phase liquid chromatography and quantified by electrospray ionization tandem mass spectrometry (ESI/MS/MS) using selected reaction monitoring. The limits of detection and quantitation of these HAAs approached 1-3 and 2-8 pg/mL, respectively, using only 0.3 mL of urine for analysis. Full product ion spectra were acquired to corroborate analyte identities. The pretreatment of urine from human volunteers that had consumed a grilled beef meal with acid or base at 70°C increased the concentration of HAAs by as much as 6-fold, indicating the presence of phase II conjugates of the parent compounds. HAAs containing an N-methylimidazole moiety undergo facile cleavage of the N-methyl group under collision-induced dissociation conditions, and MS/MS analysis in the constant neutral loss scan mode monitoring the transition [M + H]+ → [M + H - CH3.]+ revealed the presence of two other HAAs. 2-Amino-3-methylimidazo[4,5-f]quinoxaline (IQx) was identified by coelution of the analyte with synthetic IQx and by acquisition of the product ion spectrum. The second HAA was present in a relatively high abundance in urine. The molecule had the same nominal mass as 8-MeIQx (MH + at m/z 214), and the product ion spectrum was similar to that of 8-MeIQx. This novel HAA was also found in the grilled meat consumed by the volunteers at a concentration of 8 parts per billion. The accurate mass measurement and product ion spectrum of this molecule by ESI quadrupole time-of-flight mass spectrometry revealed that it was an isomer of 8-MeIQx. This tandem solvent solid phase extraction LC/ESI/MS/MS procedure may be used to rapidly assess the daily exposure to a variety of HAAs in urine.
AB - A rapid and facile tandem solvent solid phase extraction method was established to isolate the heterocyclic aromatic amines (HAAs) 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (8-MeIQx), 2-amino-3,4,8- trimethylimidazo[4,5-f]quinoxaline, 2-amino-1-methyl-6-phenylimidazo-[4,5-b] pyridine, and 2-amino-9H/-pyrido[2,3-b]indole from urine. The HAAs were separated by reversed phase liquid chromatography and quantified by electrospray ionization tandem mass spectrometry (ESI/MS/MS) using selected reaction monitoring. The limits of detection and quantitation of these HAAs approached 1-3 and 2-8 pg/mL, respectively, using only 0.3 mL of urine for analysis. Full product ion spectra were acquired to corroborate analyte identities. The pretreatment of urine from human volunteers that had consumed a grilled beef meal with acid or base at 70°C increased the concentration of HAAs by as much as 6-fold, indicating the presence of phase II conjugates of the parent compounds. HAAs containing an N-methylimidazole moiety undergo facile cleavage of the N-methyl group under collision-induced dissociation conditions, and MS/MS analysis in the constant neutral loss scan mode monitoring the transition [M + H]+ → [M + H - CH3.]+ revealed the presence of two other HAAs. 2-Amino-3-methylimidazo[4,5-f]quinoxaline (IQx) was identified by coelution of the analyte with synthetic IQx and by acquisition of the product ion spectrum. The second HAA was present in a relatively high abundance in urine. The molecule had the same nominal mass as 8-MeIQx (MH + at m/z 214), and the product ion spectrum was similar to that of 8-MeIQx. This novel HAA was also found in the grilled meat consumed by the volunteers at a concentration of 8 parts per billion. The accurate mass measurement and product ion spectrum of this molecule by ESI quadrupole time-of-flight mass spectrometry revealed that it was an isomer of 8-MeIQx. This tandem solvent solid phase extraction LC/ESI/MS/MS procedure may be used to rapidly assess the daily exposure to a variety of HAAs in urine.
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U2 - 10.1021/tx049910a
DO - 10.1021/tx049910a
M3 - Article
C2 - 15310244
AN - SCOPUS:4344717032
SN - 0893-228X
VL - 17
SP - 1121
EP - 1136
JO - Chemical research in toxicology
JF - Chemical research in toxicology
IS - 8
ER -