Determination of hemoglobin adduct of a musk xylene metabolite in trout as biomarker of exposure by gas chromatography mass spectrometry

Musk xylene (MX) is frequently used as fragrances in formulation of personal care products. Quantification of a bound 4-amino-MX(4-AMX) as cysteine adducts in trout hemoglobin (Hb) was made by gas chromatography-ion trap-mass spectrometry (GC/MS). The Hb samples were collected from trout after 24 h exposure to MX at 10 μg/g, and or menhaden oil (control). The formation of cysteine-Hb adduct was observed from nitroso derivative of MX, released by alkaline hydrolysis. The released 4-AMX metabolite was extracted in n-hexane. The extract was then reduced by evaporation, and analyzed by GC/MS. When similar agreement of mass spectral features and retention time of 4-AMX were obtained in both standard and sample solutions, the presence of 4-AMX metabolite in the Hb was confirmed. The concentration of 4-AMX was found to be 3.1 × 10^-6 - 6.9 × 10^-6 mg/g in the Hb solution. Quantitation was made based on an internal standard, a calibration plot, and response factor. In the non-hydrolyzed and laboratory blank extracts, the 4-AMX metabolite was not detected. Additionally, coeluting and interfering ions were observed in the biological samples.