ISSN:
1432-1246
Keywords:
Key words Dichlorobenzidine
;
Hemoglobin adducts
;
Biological monitoring
;
GC/MS-NCI
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract A method based on gas chromatography/ mass spectrometry–negative ion chemical ionization detection (GC/MS-NCI) was developed for the determination of 3,3′-dichlorobenzidine (DCB)-hemoglobin adducts. Adducts were released from hemoglobin by mild alkaline hydrolysis and determined by GC/MS-NCI after extraction and derivatization with heptafluorobutyric anhydride (HFBA). 2,2′-DCB was used as internal standard and the recovery of the diarylamine derivatives in the overall procedure was 65–88%. The limit of detection attained was below 0.1 ng/g hemoglobin for DCB as well as for the metabolite N-acetyl-3,3′-dichlorobenzidine (acDCB). The method was shown to be linear up to 150 ng/g hemoglobin. In the NCI mass spectra of the HFB derivatives the dominant ion is (M–HF)-. Due to the presence of two chlorines in the diarylamines, the characteristic ratio of 1.5 for m/z 624 to 626 (for diHFB-DCB and diHFB-2,2′-DCB) and m/z 470 to 472 (for HFB-acDCB) can be observed and used for identification. The method was applied to the determination of DCB-hemoglobin adducts formed in young female Wistar rats after treatment for 4 weeks with 0.006%, 0.0012% or 0.00024% DCB via the drinking water. Two adducts were detectable by GC/MS-NCI after alkaline hydrolysis of hemoglobin samples, extraction and derivatization. The structure of these adducts could be assigned to DCB and acDCB by co-chromatography with the synthetic standards and by the presence of the characteristic ion (M–HF)-. Assessment of the time dependence of hemoglobin adduct formation during subchronic treatment with DCB revealed an increase in adduct levels during weeks 1–3. After this time adduct levels essentially remained constant. In hemoglobin samples isolated from animals treated for 4 weeks with DCB a dose-proportional increase in the total amount DCB- and acDCB-hemoglobin adducts from 8.1 ng DCB/g hemoglobin at 0.3 mg/kg body weight per day (0.00024% in drinking water) to 159.9 ng DCB/g hemoglobin at 5.8 mg/kg body weight per day (0.006% in drinking water) was observed. The ratio of the DCB adduct to the acDCB adduct was strongly dose dependent. At low DCB doses the acDCB- and DCB adducts were formed at similar levels, whereas at high DCB doses the DCB adduct was predominant.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004200050142
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