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Gas chromatographic/tandem mass spectrometric identification and quantitation of metabolic 4‐acetyltoluene‐2,4‐diamine from the F344 rat
Author(s) -
Bartels Michael J.,
Timchalk Charles,
Smith Fred. A.
Publication year - 1993
Publication title -
biological mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1052-9306
DOI - 10.1002/bms.1200220309
Subject(s) - chemistry , chromatography , metabolite , urine , detection limit , tandem mass spectrometry , derivative (finance) , acetic anhydride , acetic acid , mass spectrometry , organic chemistry , biochemistry , financial economics , economics , catalysis
2,4‐Toluenediamine (TDA) and 2,4‐toluenediisocyanate (TDI) are metabolized in the Fischer 344 rat to monoacetyl‐2,4‐toluenediamine (Ac‐TDA) and diacetyl‐2,4‐toluenediamine (Ac 2 ‐TDA). A gas chromatographic/tandem mass spectrometric (GC/MS/MS) method was developed to characterize the structure of the Ac‐TDA metabolite (2‐acetyl versus 4‐acetyl), as a D 3 ‐diacetyl‐TDA derivative. This method was also shown to be useful in the measurement of urinary levels of TDA, Ac‐TDA and Ac 2 ‐TDA. Urine samples (1.0 g) were adjusted to pH 6.5–7.0, fortified with the internal standard D 9 ‐Ac 2 ‐TDA (D 3 ‐ring + D 3 ‐acetyl × 2) and extracted with ethyl acetate (2 × 2 ml). The extract residues were then derivatized with D 6 ‐acetic anhydride and analyzed via electron impact GC/MS/MS. MS/MS analysis of the D 3 ‐Ac 2 ‐TDA derivative of the two Ac‐TDA isomers yielded different daughter ion spectra from the common parent ion ( m/z 209). Analysis of urine samples from rats administered TDA (p.o., i.v.) and TDI (p.o., inhalation) indicated that all of the metabolic Ac‐TDA from these test materials was the 4‐acetyl‐TDA isomer. Subsequent GC/MS analysis of the heptafluorobutyric acid (HFBA) derivative of this metabolite confirmed the MS/MS results. Selected ion monitoring of the M‐acetyl daughter ions from the derivatized TDA, Ac‐TDA and Ac 2 ‐TDA was shown to be a useful technique for quantitation of urinary levels of these compounds, with a detection limit of 35 ng g −1 urine for TDA and 10 ng g −1 urine for Ac‐TDA and Ac 2 ‐TDA.