Low-Density Solvent Based Dispersive Liquid-Liquid Microextraction Combined with Graphite Furnace Atomic Absorption Spectrometry for the Determination of Trace Lead and Cadmium in Domestic Water
ZHANG Han, XUE Ai-fang, CHEN Hao, LI Sheng-qing*
Department of Chemistry, College of Science, Huazhong Agricultural University, Wuhan 430070, China
Abstract A simple and efficient method for the determination of Pb and Cd in domestic water and drinking water was developed by combining low-density solvent based dispersive liquid liquid microextraction (LDS-DLLME) with graphite furnace atomic absorption spectrometry (GFAAS). In the LDS-DLLME, a mixed solution of octanol (extraction solvent) and methanol (dispersive solvent) was rapidly injected into the sample solution by a microsyringe to form a cloudy emulsion. With diethyldithiocarbamate (DDTC) as chelating agent, Pb2+ and Cd2+ were extracted into the highly dispersed octanol microdroplets. The mixture was then centrifuged and the chelates of Pb and Cd moving into the organic phase, which was analyzed by GFAAS subsequently. In addition, the experimental conditions were investigated and optimized, such as the type and volume of extractant and dispersant, pH, DDTC concentration and extraction time. Under the optimal experimental conditions, the detection limits of Pb and Cd were 0.15 and 0.03 μg·L-1, and enrichment factors were 87 and 48, respectively, with good linearity and precision. This method has the advantages of simplicity, rapidity, low cost, and high enrichment. It is successfully applied to the determination of trace Pb and Cd in tap water, drinking water and South Lake water.
[1] Janardhan Reddy Koduru, Kap Duk Lee. Food Chemistry.，2014, 150: 1.
[2] WHO (World Health Organization). Fifty-Third Report of the Joint FAO/WHO Expert Committee on Food Additives, WHO Technical Report Series 896，2000.
[3] FAN Chun-hui，DU Bo，ZHANG Ying-chao，et al(范春辉，杜 波，张颖超，等). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2016, 36(8): 2625.
[4] Li Shengqing, Cai Shun, Hu Wei, et al. Spectrochimica Acta Part B, 2009, 64(7): 666.
[5] Zhang Chunyan, Wang Yining, Cheng Xiangrong, et al. Journal of the Chinese Chemical Society, 2011, 58(7): 919.
[6] LI Jing-xi, SUN Cheng-Jun, ZHENG Li, et al. Chinese Journal of Analytical Chemistry，2016, 44(11): 1659.
[7] LI Zi-chao，JIANG Zhi-gang(李子超，江志刚). Food Science and Technology(食品科技), 2006, 74(8): 242.
[8] WU Qiong，MENG Ling-ju，KANG Qi-nan，et al(吴 琼，孟玲菊，康琪楠，等). Shandong Chemical Industry(山东化工), 2017, 46(5): 71.
[9] Mohammad Rezaee, Yaghoub Assadi, Mohammad-Reza Milani Hosseini, et al. Journal of Chromatography A, 2006, 1116(1): 1.
[10] Li Xiaoyi, Xue Aifang, Chen Hao, et al. Journal of Chromatography A, 2013, 1280: 9.
[11] ZHU Ben-qiong, CHEN Hao, LI Sheng-qing(祝本琼，陈 浩，李胜清). Chinese Journal of Chromatography(色谱), 2012, 30(2): 201.
[12] Estefanía M Martinis, Paula Bertón, Jorgelina C Altamirano, et al. Talanta, 2010, 80(5): 2034.
[13] Ricardo E Rivas, Ignacio Lopez-Garcia，Manuel Hernandez-Cordob. Anal. Methods, 2010, 2(3): 225.
[14] MA Xiao-guo, LUO Song-hua, ZENG Qian(马晓国，罗颂华，曾 倩). Ecology and Environmental Sciences(生态环境学报), 2011, 20(12): 1909.
[15] CHEN Yan-yan, FAN Zhe-feng(陈艳艳，范哲锋). Chinese Journal of Analysis Laboratory(分析试验室), 2015, 34(10): 1215.
[16] GB 5749—2006. Standards of Drinking Water Quality(生活饮用水卫生标准). National Standards of the People’s Republic of China(中华人民共和国国家标准)，2006.
[17] GB 3838—2002. The Quality Standards of Surface Water Environment(地表水环境质量标准). National Standards of the People’s Republic of China(中华人民共和国国家标准)，2002.
