On-line solid phase extraction-hydride generation atomic fluorescence spectrometric determination of trace arsenic in high purity antimony(III) oxide

摘要

The determination of As(III) in high purity Sb_2O_3 was taken as example to illustrate a high selective solid phase extraction (SPE) with non-polar resins as the sorbent. The extraction was based on the fact that in concentrated HCl solutions, As(III) forming molecular covalent AsCl_3 could be attracted by the hydrophobic phase of the resins, whereas the matrix Sb existing only as the ionic Sb-Cl complex could not be adsorbed. The SPE column was made from the Amberlite XAD-16 resin and was on-line coupled with hydride generation atomic fluorescence spectrometer for As(m) detection. Under the optimized conditions, the detection limit (3σ) of 0.26 μg g~(-1), the RSD (n = 6) of 6.2% for 50 μg L~(-1) of As(III) and a linear calibration curve from 2 μg L~(-1) to 200 μg L~(-1) with R = 0.9998 were obtained. The recoveries for 10 μg L~(-1) of As(III) spiked in 1 g L~(-1) of Sb(III) solution was in the range of 97-102%. The method was applied to the determination of trace As(m) in two highly pure Sb_2O_3 samples.