SYNTHESIS AND USE OF DEUTERATED FENAMIPHOS AND ITS METABOLITES AS INTERNAL STANDARDS FOR MASS-SPECTROMETRIC ANALYSIS IN WATER

The applications of mass spectrometry (MS) are increasing in environme ntal analysis, pesticides measurement in particular. To take full adva ntage of the capabilities of MS it is important to have available labe led standards that enhance the performance of the quantitative analysi s, increasing its accuracy and precision. We synthesized a series of d euterated internal standards corresponding to fenamiphos (Ia) and some of its metabolites, using rapid procedures and inexpensive materials. The use of afluoropropyl)-2-(nonafluorobutyl)-cis-oxaziridine (IV) wa s particularly attractive for the preparation of oxidative metabolites of fenamiphos (Ia), analytical and deuterated standards. We used thes e compounds for the analysis of these pollutants in water. We used sol id-phase extraction, testing several materials, and supercritical flui d extraction techniques. The analysis was done by gas chromatography-m ass spectrometry, with the selected ion monitoring (SIM) technique, ob taining good results with the oxidative metabolites of compound Ia (co mpounds IIa and IIIa). For the more polar metabolites Ib, IIb and IIIb , liquid chromatography-mass spectrometry analysis in the SIM mode gav e the best result.