Simultaneous determination of formate and acetate in whole blood and urine from humans using gas chromatography–mass spectrometry

We devised a sensitive and simple method for simultaneous determination of formate and acetate in whole blood and urine from humans using gas chromatography–mass spectrometry. Formate and acetate were alkylated with pentafluorobenzyl bromide in the mixture of acetone and phosphate buffer (pH 6.8). The derivatives obtained were analyzed using gas chromatography–mass spectrometry in positive-ion electron ionization (EI) mode. The lower limit of detection for both compounds was 0.02 mM. The calibration curves for formate and acetate were linear over the concentration range from 0.05 to 5.0 mM. Accuracy and precision of the method were evaluated and the coefficients of variation were within 10%. With use of this method, levels of formate and acetate in whole blood can be determined in forensic cases.