Detection of metabolites of toxic alkylmethylphosphonates in biological samples

The major metabolites and breakdown products of some toxic organophosphonates are their respective alkymethylphosphonic acids. These acids ionize at physiological pH and are not amenable to gas chromatographic analysis in their underivatized forms. Their detection in biological samples has been difficult because of their presence at only trace levels. Existing analytical methods were developed mainly for measuring these phosphonic acids in environmental samples and at higher concentrations. In this study, we devised a gas chromatographic/mass spectrometric method to provide confirmation and quantification of the organophosphonic acids of soman (GD), sarin (GB) and GF in blood and urine. This report describes the various derivatization conditions that we have studied and demonstrates the characteristic mass spectra by different ionization techniques.