Comparison of sodium tetraethylborate and sodium tetra(n-propyl)borate as derivatization reagent for the speciation of organotin and organolead compounds in water samples.

The influence of pH on the propylation with sodium tetra(n-propyl)borate of butyl- and phenyltins as well as for trimethyl- and triethyllead was investigated. Ethylation and propylation with tetraalkylborates were compared with regard to derivatization yields and figures of merit for organotin compounds in real water samples. Similar results for limit of detection (3-12 ng/L as tin), derivatization yield (40-100%) and relative standard deviation of the method (3-10%) were achieved for derivatization with the two tetraalkylborates. Propylation is thus the preferred method for the simultaneous determination of environmentally relevant organotin and organolead compounds. The handling of the hygroscopic and air sensitive reagents NaBEt4 and NaBPr4 was simplified by dissolving them in tetrahydrofurane. The reagent solutions in tetrahydrofurane can be stored for at least one month at 4 degrees C in the dark without observing any decrease in the derivatization efficiency.