Microchip-Based Liquid Liquid Extraction Using Isotope Dilution ICP-MS for Trace Copper Determination in Steels

We demonstrated microchip-based solvent extraction and back extraction using isotope dilution inductively coupled plasma mass spectroscopy (IDMS/ICP-MS) for trace copper determination in steels. In this method, copper was rapidly separated from the matrix element and its concentration was determined. Cu was extracted into o-xylene using 8-hydroxyquinoline at pH 7 and back extracted with 0.1 mol L-1 nitric acid at a flow rate of 20 mu L min(-1). The Cu concentration was determined using IDMS. The time taken for the extraction/back extraction was about 1 s on the microchip and the total measurement time using IDMS/ICP-MS was about 40 s per sample. The proposed method was used for Cu determination in a JSS601-10 steel standard. The obtained analytical results were in good agreement with the certified values.