Sodium tetra( n-propyl)borate: a novel aqueous in situ derivatization reagent for the simultaneous determination of organomercury, -lead and -tin compounds with capillary gas chromatography–inductively coupled plasma mass spectrometry

Abstract

The versatility of sodium tetra( n-propyl)borate, NaBPr 4, as aqueous in situ derivatization reagent for organometallic compounds is demonstrated. With this new derivatization reagent it is now possible to derivatize the important ethyl derivatives of lead and mercury which until now had to be derivatized by Grignard alkylation or hydride generation. The synthesis of NaBPr 4 is described in detail. Derivatization parameters such as pH, reaction time, amount of reagent and stability of the aqueous NaBPr 4 solution were investigated. Different organometallic compounds of tin, mercury and lead were simultaneously determined by an inductively coupled plasma mass spectrometer coupled to the capillary GC system using a laboratory-developed interface. Good linearity was obtained for all components with detection limits in the ng/l range (without preconcentration). The reproducibility of the complete procedure, i.e. derivatization, extraction and injection, is better than 10% R.S.D. The analysis of the PACS-1 Reference Material after derivatization with NaBPr 4 showed the accuracy of this method.