High-Temperature, Microwave-Assisted UV Digestion: A Promising Sample Preparation Technique for Trace Element Analysis

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• 作者：Dieter Florian and Gü ; nter Knapp
• 刊名：Analytical Chemistry
• 出版年：2001
• 出版时间：April 1, 2001
• 年：2001
• 卷：73
• 期：7
• 页码：1515 - 1520
• 全文大小：202K
• 年卷期：v.73,no.7(April 1, 2001)
• ISSN：1520-6882

文摘

A novel, microwave-assisted, high-temperature UV digestion procedure was developed for the accelerated decomposition of interfering dissolved organic carbon (DOC)prior to trace element analysis of liquid samples such as,industrial/municipal wastewater, groundwater, and surface water, body fluids, infusions, beverages, and sewage.The technique is based on a closed, pressurized, microwave digestion device. UV irradiation is generated byimmersed electrodeless Cd discharge lamps (228 nm)operated by the microwave field in the oven cavity. Toenhance excitation efficiency an antenna was fixed on topof the microwave lamp. The established immersion systemenables maximum reaction temperatures up to 250-280C, resulting in a tremendous increase of mineralizationefficiency. Compared to open UV digestion devices, decomposition time is reduced by a factor of 5 and themaximum initial concentration of DOC can be raised byat least a factor of 50. The system's performance on a real-type sample was evaluated for the mineralization ofskimmed milk (IRMM, CRM 151) and subsequent determination of trace elements using standard spectroscopic techniques. Recovery for Cd (109%), Cu (112%),Fe (99%), and Pb (96%) showed good agreement with the95% confidence interval of the certified values.