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摘要
In this work, the authors proposed a new liquid membrane-based method for the determination of lead in saline waters. In this case, the new method is based on lead quantification by inductively coupled plasma-mass spectrometry (ICP-MS) after a preconcentration step by means of a bulk liquid membrane (BLM) system. With no sample manipulation, the system transports and preconcentrates the analyte ions in the sample into the acidic receiving solution, by means of an organic membrane containing di-(2-ethylhexyl)-phosphoric acid (DEHPA) acting as a chemical carrier. The chemical variables controlling Pb2+ permeation through the membrane were studied by use of a modified simplex approach. The most appropriate preconcentration rates were found at sample pH 4.7, maintained with a 0.08-M acetate buffer solution, a 0.07-M DEHPA concentration, and a 0.23-M HNO3 receiving solution. Under these conditions, an extraction yield of 93.8 +/- 0.1% and a preconcentration factor of 4.2 were obtained, thus allowing lead selective separation and accurate determination in real samples at environmental concentration levels. The system was tested with several real samples from the Gulf of Cadiz containing lead at the low ppb levels.
- 出版日期2011
