Purge-Trap Method for Determination of Tributyltin by Atomic Absorption Spectrometry

This chapter describes direct determination of sub-nanogram amounts of methyl- and butyltin compounds, particularly tributyltin, in aqueous environmental samples, plant extracts, and shellfish extracts by two similar methods. Both procedures use purge-and-trap methods following derivatization with sodium borohydride that allows concentration of organotin hydrides in a trap at liquid nitrogen temperature (-196°C). The organotin hydride species are eluted from the trap and are atomized in a quartz burner mounted in an atomic absorption spectrophotometer. The chapter discusses advantages and disadvantages of the two methods. Automation of one method permits near-real-time, aboard-ship determinations of tributyltin in seawater under in-situ conditions.