Quantitation of methylated hemoglobin via hydrolysis of methyl esters to yield methanol.

Methyl esters formed by methylation of carboxylic acid groups on hemoglobin can be quantitated via GC/MS negative-ion chemical ionization analysis of the pentafluorobenzoate derivative of the methanol released from the hemoglobin upon base hydrolysis. Although the method requires extensive cleanup of extracting solvents because of the ubiquitous presence of trace levels of methanol, it is possible to quantitate adducted hemoglobin at levels as low as 4 ng per gram of hemoglobin using [13C, 2H3]methyl alcohol as the internal standard. In principle this method can be used in humans as a dosimeter for exposure to environmental methylating or alkylating agents.