A novel non-ionic nanoaggregate sensitized salt induced cloud point extraction of anionic beryllium-chrome azurol S for spectrophotometric determination of beryllium in environmental waters

摘要

A simple non-ionic nanoaggregate sensitized and salt induced cloud point extraction (NS-CPE) procedure was reported for the ultra-trace determination of beryllium in environmental waters using spectrophotometer. Chrome azurol S (CAS) and Triton X-114 were used as chelating and extracting agents, respectively. The CAS forms hydrophilic, thermally labile and coloured binary Be-(CAS)(2)(4-) complex with beryllium. This complex was sensitized by non ionic micelles of Triton X-114, which was further improved by the addition of salt. Moreover, these micellar interactions facilitated room temperature phase separation of coloured Be-(CAS)(2)(4-) which settled at the bottom of the test tube as a surfactant rich phase. This synergetic process enhanced the binary beryllium complex absorptivity from 1.9 x 10(4) to 9.2 x 10(5) L mol(-1) cm(-1), which is 50 times more compared to direct measurement. This process also avoided the usual blank bias error that occurs with cationic mixed micelles due to the presence of excess of deprotonated CAS used for complexation. The limit of detection and pre-concentration factors were 0.2 ng mL(-1) and 10 respectively. At 2-50 ng mL(-1) of beryllium, the obtained recoveries were in the range 85-98% with 1-5% relative standard deviation.