Gas chromatographic/tandem mass spectrometric identification and quantitation of metabolic 4-acetyltoluene-2,4-diamine from the F344 rat.
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 (Ac2-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 D3-diacetyl-TDA derivative. This method was also shown to be useful in the measurement of urinary levels of TDA, Ac-TDA and Ac2-TDA. Urine samples (1.0 g) were adjusted to pH 6.5-7.0, fortified with the internal standard D9-Ac2-TDA (D3-ring + D3-acetyl x 2) and extracted with ethyl acetate (2 x 2 ml). The extract residues were then derivatized with D6-acetic anhydride and analyzed via electron impact GC/MS/MS. MS/MS analysis of the D3-Ac2-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 Ac2-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 Ac2-TDA.
Bartels
M J
MJ
Health and Environmental Sciences, Dow Chemical Company, Midland, Michigan 48674.
Timchalk
C
C
Smith
F A
FA
D000818:Animals; D005466:Fluorocarbons; D008401:Gas Chromatography-Mass Spectrometry; D007202:Indicators and Reagents; D007536:Isomerism; D008297:Male; D010655:Phenylenediamines / Q000378:metabolism / Q000652:urine; D051381:Rats; D011916:Rats, Inbred F344; D014051:Toluene 2,4-Diisocyanate / Q000378:metabolism / Q000652:urine; D014052:Toluidines / Q000652:urine*
D005466:Fluorocarbons; D007202:Indicators and Reagents; D010655:Phenylenediamines; D014052:Toluidines; D014051:Toluene 2,4-Diisocyanate; C033094:perfluorobutyric acid; C025107:4-acetylamino-2-aminotoluene; C010914:2,4-diaminotoluene