Determination of lead in soybean sauces by the diffusive gradients in thin films technique

A diffusive gradients in thin films (DGT) device with sodium poly (aspartic acid) (PASP) as a novel binding agent (PASP DGT) combined with graphite furnace atomic absorption spectrometry (GFAAS) was developed for the sampling and measurement of lead in soybean sauce samples. The performance of PASP DGT was independent of pH in the range of 3–6 and salinity in the range from 4 to 14 g/L (as NaCl). There was no significant difference between PASP DGT technique and hydride generation atomic fluorescence spectrometry (HG-AFS) method for the measurement of lead in soybean sauce samples. The recoveries of lead in spiked soybean sauce samples determined by PASP DGT coupled with GFAAS were 94.3–97.2% with the relative standard deviations of 2.52–3.09%. The concentrations of Pb in twelve soybean sauce samples determined by PASP DGT coupled with GFAAS were in the range of 0.09–0.71 mg/L.