GFAAS中有机基体改进剂消除食盐基体干扰的研究

Study of Organic Matrix Modifiers for Elimination of Salt Matrix Interference in GFAAS

为探讨有机基体改进剂消除食盐基体干扰的效果和作用机理,采用维生素C、草酸、酒石酸和草酸作为基体改进剂,比较加入有机基体改进剂前后石墨炉原子吸收光谱法测定Pb、Cu和Cd3个元素的信背比、原子吸收信号与背景的峰值信号的峰型、原子化温度、回收率和精密度。结果表明:采用有机基体改进剂后,原子化信号和背景信号分离,原子化温度降低了100～450℃,信背比提高了5.1～45.8倍。精密度优于5.2%,实际样品的回收率为91.0%～107%。说明有机基体改进剂可有效消除食盐的基体干扰,其作用机理为由于有机基体改进剂本身的表面活性和络合作用,分解产物形成强还原气氛。

To study the effect of organic reagent as matrix moditicr tor eliminating the salt matrix mtertcrence and its mecnamsm, ascorbic acid, citric acid, tartaric acid and oxalic acid were used as matrix modifier in the determination of Pb, Ca and Cd by GFAAS. The analytical information before and after adding organic matrix modifiers were compared. After the addition of organic matrix modifiers, the atomization signal and background signal were separated, atomization temperatures decreased enormously, the ratios of atomization signal to background signal increased and the RSDs and recoveries of practical samples improved obviously, It was concluded that organic matrix modifiers can eliminate salt matrix interference effectively, The mechanism of the effect of the organic matrix modifiers is suggested to be caused by the reductive substances produced by the decomposition of the orgaaic additives as well as the complexing action and the melt-assisting action of the organic additives.