Ultraperformance Liquid Chromatography Tandem Mass Spectrometry Method To Determine Formaldehyde Hemoglobin Adducts in Humans as Biomarker for Formaldehyde Exposure

Formaldehyde (FA) is an environmental chemical classified as a human carcinogen. It is highly reactive and can bind covalently with hemoglobin (Hb) to produce Hb adducts. Measurement of these Hb adducts provides valuable information about exposure to this chemical. We developed a robust, ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for quantifying FA-Hb adducts in red blood cells. The method measures the FA-VHLTPEEK peptide after trypic digestion. The peptide is a FA adduct at the N-terminus of the beta chain of human Hb. Method mean (±SD) accuracy, determined by recovery in quality control and blank material was 103.2% ± 8.11. The mean among-day and within-day coefficients of variation determined at three concentration levels (%CV) were 9.2% (range: 7.2-10.2%) and 4.9% (range 3.1-7.3%), respectively. The limit of detection was 3.4 nmol/g Hb. This method was applied to the analysis of 135 human blood samples, and FA-VHLTPEEK was detected in all study samples. FA-VHLTPEEK concentrations were not significantly different between smokers and nonsmokers. This work is the first validated UPLC-MS/MS method in which a FA peptide derived from a FA-Hb adduct could be used to monitor exposure to FA in population studies.