Long-term Stability of Human Aflatoxin B1 Albumin Adducts Assessed by Isotope Dilution Mass Spectrometry and High-Performance Liquid Chromatography–Fluorescence

• Published in: Cancer epidemiology, biomarkers & prevention biomarkers & prevention, 2008-06, Vol.17 (6), p.1436-1439
• Main Authors: SCHOLL, Peter F, GROOPMAN, John D
• Format: Article
• Language: English
• Subjects: adduct; aflatoxin; Aflatoxin B1; Aflatoxins - analysis; albumin; Biological and medical sciences; Chromatography, High Pressure Liquid - methods; Environmental Exposure; Female; fluorescence; Humans; isotope dilution; Lysine - analysis; Male; Mass Spectrometry - methods; Medical sciences; molecular dosimetry; serum; Serum Albumin - chemistry; stability; Tumors
• ISSN: 1055-9965; 1538-7755
• DOI: 10.1158/1055-9965.EPI-07-2926

The measurement of the aflatoxin B 1 -lysine serum albumin adduct in human blood samples is the most facile biomarker for the assessment of chronic exposure to aflatoxin B 1 . Many technologies have been developed for the measurement of this protein adduct including immunoassays, high-performance liquid chromatography (HPLC) with fluorescence detection, and a newly developed isotope-dilution mass spectrometry method. Irrespective of the technology used to determine this adduct level, an important question remains about the long-term stability of this damage product in stored samples. To address this issue, 19 human serum samples that had been previously analyzed for the aflatoxin B 1 -lysine adduct by high-performance liquid chromatography–fluorescence in 1989 were re-analyzed by isotope dilution mass spectrometry after storage at −80°C. The adduct concentrations measured by these two techniques were identical within 4% over the range 5 to 100 pg of aflatoxin B 1 -lysine/mg albumin. In addition, the specific chemical structure of the aflatoxin B 1 -lysine adduct in human samples was confirmed for the first time by collision-induced dissociation full scan mass spectrometry analysis of the protonated adduct molecular ion. These results illustrate that the aflatoxin B 1 -lysine serum albumin adduct can be stable in human serum stored at −80°C since 1989, and this provides confidence for the measurement of this biomarker in repository samples from epidemiologic investigations. (Cancer Epidemiol Biomarkers Prev 2008;17(6):1436–9)