APDC—MIBK萃取流动注射—原子吸收法测定肥料中微量镉

APDC 和MIBK 混合液,经短的分隔后与含有镉的试液混合,经过反应管进行络合萃取反应,再通过一个相分离器,将含有镉的有机相导入原子吸收进行测定.文中对一些反应参数如流动速度,反应管长度,溶液酸度以及与肥料有关的外来离子影响及其消除干扰的方法进行了试验.本法能以每小时24个试样的速度测量,可含有1—50ppb 镉的溶液,其灵敏度与原子吸收直接吸入法相比可增大至23倍.本法用于测定几个肥料样品,回收率为98%左右,相对标准偏差为1.9%.用本法的流程图测定Cu,Fe,Co,Pb,Ni,Ag 和Zn 等七个元素最佳酸度条件及灵敏度的结果有参考价值.

Determination of Cadmium in Fertilizer by Atomic Absoption Spectrometry After APDC-MIBK Extraction in Continous Flow

In the method,Ammonium pyrrolidinedithiocarbamate(APDC)wasmixed with methyl isobutyl ketone(MIBK)first,after a short segmen-tation they were mixed with an acidic digestion solution of fertilizer.Theyreacted and extracted in an extraction coil.The organic extract was ledinto an atomic absorption spectrometer(AAS)through a phase separator.The proposed method can be used to determine cadmium in digestionsolution of fertilizer down to 1 ppb at a rate of about 24 samples perhour.An increase in sensitivity of 23 times is achived in comparition withdirect aspiration of aqueous solution.APDC consumption was 0.9mg/minand MIBK consumption was 0.3ml/min.The r.s.d.was 1.9% and therecovery of added cadmium was 98%.