磁性聚电解质多层膜固相萃取-火焰原子吸收光谱法测定水样中的三价铬

Determination of trivalent chromium in water by magnetic polyelectrolyte multilayer solid phase extraction-flame atomic absorption spectrometry

将聚电解质多层膜组装于磁性硅胶表面得到新型吸附剂;将该新型吸附剂用于磁性固相萃取(MSPE),并与火焰原子吸收光谱检测联用分析水样中的Cr3+;优化了样品的pH、洗脱条件和超声时间等影响MSPE萃取效率的参数.结果表明,在优化的测试条件下,该方法的检出限(3σ)为1.7μg·L-1,相对标准偏差为2.1%,富集倍数为15.9,可用于测定合成水样中的Cr3+.

Polyelectrolyte multilayers were assembled on the surface of magnetic silica gel to form a novel sorbent. As-obtained novel sorbent was used for magnetic solid phase extraction （MSPE） and combined flame atomic absorption spectrometry to determine Cr3＋ in water. The experimental parameters including pH value of the water sample, elution condition, and ultra- sonic irradiation time were optimized in relation to their effects on the extraction efficiency of MSPE. Results indicate that, under the optimized testing condition, the limit of detection （3a） of the established method is 1.7 g .L-1, the relative standard deviation is 2.1, and the en- richment factor is 15.9. The present method has been successfully applied to the determination of trace Cr3＋ in synthetic water samples.