Dispersive liquid-liquid microextraction using diethyldithiocarbamate as a chelating agent and the dried-spot technique for the determination of Fe, Co, Ni, Cu, Zn, Se and Pb by energy-dispersive X-ray fluorescence spectrometry

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• 作者：Karina Kocot ; Beata Zawisza ; Rafal Sitko
• 关键词：EDXRF ; Preconcentration ; Trace metal ; Liquid&ndash ; liquid microextraction ; Water sample
• 刊名：Spectrochimica Acta Part B: Atomic Spectroscopy
• 出版年：2012
• 出版时间：July, 2012
• 年：2012
• 卷：73
• 期：Complete
• 页码：79-83
• 全文大小：517 K

文摘

Dispersive liquid-liquid microextraction (DLLME) using sodium diethyldithiocarbamate (DDTC) as a chelating agent was investigated for the simultaneous determination of iron, cobalt, nickel, copper, zinc, selenium and lead ions in water samples. The procedure was performed using 5 mL of the sample, 100 ¦ÌL of a 0.5 % solution of DDTC, 30 ¦ÌL of carbon tetrachloride (extraction phase) and 500 ¦ÌL of methanol (disperser solvent). The experiments showed that Fe, Co, Ni, Cu, Zn and Pb can be simultaneously extracted at a pH of 5 and that Se can be extracted at a pH of 2-3. The results were compared with those obtained using ammonium pyrrolidine dithiocarbamate as a chelating agent. For all analytes, a linear range was observed up to 0.4 ¦Ìg mL^? 1. If Fe and Zn are present in concentrations 10 times higher than those of the other analytes, then the linearity is observed up to 0.2 ¦Ìg mL^? 1. In the present study, the organic phase that contained preconcentrated elements was deposited onto a Millipore filter and measured using energy-dispersive X-ray fluorescence spectrometry. The obtained detection limits were 2.9, 1.5, 2.0, 2.3, 2.5, 2.0 and 3.9 ng mL^? 1 for Fe, Co, Ni, Cu, Zn, Se and Pb, respectively. This combination of DLLME and the dried-spot technique is promising for multielement analyses using other spectroscopy techniques, such as laser ablation©\inductively coupled plasma©\mass spectrometry, laser-induced breakdown spectroscopy or total-reflection X-ray fluorescence spectrometry.