空气混合流动注射-编结反应器预富集-火焰原子吸收光谱法测定水样中痕量铅

An air mixing sorption flow injection preconcentration in a knotted reactor coupled with flame atomic absorption spectrometry for determination of trace lead in water

建立了一种环保，高效，简便的流动注射空气混合吸附预富集与火焰原子吸收光谱法联用测定水样中痕量铅的新方法。样品溶液、络合剂和空气3股进样，金属离子和络合剂在线混合反应，其络合物流经编结反应器（KR）并吸附在KR内壁，通入一段空气流，防止前后溶液混合，用乙醇洗脱后送入火焰原子吸收检测器进行测定。在预富集阶段，空气流的引入，增加了金属离子络合物的吸附效果，提高了浓集系数（EF）。与多步吸附预富集相比，减少了样品富集时间，达到了更好的吸附富集效果。样品富集流速为4．8mL／min，富集时间60s，Pb2＋的EF为46，样品输出率为40／h，方法检出限为4．8μg／L，对0．50mg／L Pb2＋测定的相对标准偏差（n=11）为2．3％。以三乙醇胺为掩蔽剂，测定在水样中Pb2＋的回收率范围为97．4％～100．9％。

An environmentally friendly,sensitive and simple method was developed for the determination of trace lead in water samples by air mixing sorption flow iniection（FI） on-line preconcentration procedure in a knotted reactor coupled with flame atomic absorption spectrometry（FAAS）. The sample,complexing agent,and air were merged on-line. The complex compound formed by metal ion and complexing agent was flew through the knotted reactor（KR） and adorbed onto the inner walls of the KR. After this, an air flow was introduced into the KR in order to prevent former and latter solution from being mixed. Then ethanol was employed to elute the adsorbed complex compound and deliver the analyte into the FAAS system for on-line detection. During the preconcentration procedure, the adsorption effect of complex compound onto the inner walls of the KR, and the enhancement factor （EF） were increased by introducing the air. Compared to multiplexed sorption preconentration procedure, the new method reduced the preconcentration time,and received better adsorption effect. The preconcentration time was 60 s, preconcentration flow rate was 4.8 mL/min, the EF was 46, the sample throughput was 40/h,and the detection limit （3σ） was 4.8 μg/L for lead. The relative standard deviation（RSD,n=11） was 2.3% for lead of 0.50 mg/L. The method has been applied to the determination of trace lead with the recovery from 97.4% to 100.9% using triethanolamine as masking reagent.