Bilal Muhammad, Kazi Tasneem Gul, Afridi Hassan Imran, Ali Jamshed, Baig Jameel Ahmed, Arain Mohammad Balal, Khan Mustafa
National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080, Pakistan.
National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080, Pakistan.
Spectrochim Acta A Mol Biomol Spectrosc. 2017 Aug 5;183:417-424. doi: 10.1016/j.saa.2017.04.037. Epub 2017 Apr 20.
A green tunable dispersive liquid-liquid micro extraction (TDLLME) technique was established for the simultaneous enrichment of lead (Pb) and cadmium (Cd) from different lakes water before analysis by flame atomic absorption spectrometry (FAAS). A solvent known as tunable polarity solvent (TPS), mixture of 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) and 1-decanol, has been employed as extractant in aqueous medium. In first step this mixture can be made polar by slowly bubbling the antisolvent trigger (CO) through the solution, which makes a monophasic solution. During this step hydrophobic complexes of the metals with 8-hydroxy quinoline (8-HQ) were extracted by TPS. Then the mixture was switched back to hydrophobic one by heating and/or bubbling nitrogen, turning the mixture into two phases again. In second phase the metals were leached out from the complexes entrapped in TPS, by treating with a solution of nitric acid and exposing the mixture to CO, which switched the mixture into single phase. Then N purging and/or heating again turned the mixture into two phases. The acidic aqueous phase containing the metals was introduced to FAAS for analysis, whereas TPS was recycled for next experiment. Different parameters, affecting the efficiency the technique, were optimized by multivariate approach. The method was applied to certified reference material of water and to a real sample spiked with standards of known concentration, to confirm its validity and accuracy. LOD obtained for Pb and Cd were 0.560 and 0.056μgL respectively. The developed method was applied successfully to the real water samples of two lakes of Sindh, Pakistan.
建立了一种绿色可调谐分散液液微萃取（TDLLME）技术，用于在火焰原子吸收光谱法（FAAS）分析之前，从不同湖水样品中同时富集铅（Pb）和镉（Cd）。一种称为可调谐极性溶剂（TPS）的溶剂，即1,8 - 二氮杂双环-[5.4.0]-十一碳-7-烯（DBU）和1-癸醇的混合物，被用作水相介质中的萃取剂。第一步，通过向溶液中缓慢鼓入反溶剂触发剂（CO），可使该混合物变为极性，形成单相溶液。在此步骤中，金属与8-羟基喹啉（8-HQ）形成的疏水络合物被TPS萃取。然后通过加热和/或鼓入氮气，将混合物变回疏水状态，使其再次分成两相。在第二阶段，通过用硝酸溶液处理并将混合物暴露于CO，使混合物变为单相，从而将金属从包裹在TPS中的络合物中浸出。然后再次进行氮气吹扫和/或加热，使混合物再次分成两相。含有金属的酸性水相被引入FAAS进行分析，而TPS则循环用于下一次实验。通过多变量方法优化了影响该技术效率的不同参数。该方法应用于水的标准参考物质和加标已知浓度标准品的实际样品，以确认其有效性和准确性。铅和镉的检出限分别为0.560和0.056μg/L。所开发的方法成功应用于巴基斯坦信德省两个湖泊的实际水样分析。
