Headspace microextraction of tin into an aqueous microdrop containing Pd(II) and tributyl phosphate for its determination by ETAAS

The study introduces a method for headspace solvent microextraction (HS-SME) of tin hydride into an aqueous microdrop containing Pd(II) and tributyl phosphate (TBP) as an enrichment and matrix modification method prior to ETAAS determination. The tin hydride was generated by injection of a fixed volume of sodium tetrallydroborate solution into the sample. Effects of several parameters including sample volume, amount of added NaBH4, Pd(II) and TBP concentrations in the drop, acid type and concentration in the sample, extraction time and drop volume were carefully studied. Possible interferences from a number of elements were tested and no significant interference from hydrides of other elements was observed. Salt concentrations up to 0.3 mol L-1 was tolerated by the HS-SME method while it drastically increased the background and signal absorbances in a direct injection method. The HS-SME resulted in a relatively sensitive tin determination method with a detection limit of 2.09 ng mL(-1) and a precision better than 4.04% (RSD). The method was successfully applied to the determination of tin in waste water and slurry samples.