A new method, based on the direct combination of solvent extraction with luminol chemiluminescence (CL) In a reversed micellar system of cetyltrimethylammonlum chloride-water (buffered with sodium carbonate)-6:5 (v/v) chloroformcyclohexane, Is established for the determination of gold In aqueous solutions. The Interference behavior of 15 metals on the reference gold CL signals was evaluated. By dispersing an aqueous solution of the Individual Interferent alone and In admixture with the analyte, a comparative Inquiry on their CL behavior was also carried out In the reversed micellar medium. Separation of analyte from Interferents by extraction with trln-octylphosphlne oxide In chloroform resulted In reduced or no Interference. The present method was applied to the determination of gold In Industrial samples of silver-based alloy.This work was partially supported by a Grant-in-Aid for Scientific Research, No. 04453038, from the Ministry of Education, Science, and Culture, Japan, and one of the authors, Imdadullah, also thanks this Ministry for awarding a Scholarship. We thank the Analytical Center of Sumitomo Metal Mining Co., Ltd., Niihama, Japan, for providing us silver-based alloy samples.

The chemiluminescence (CL) reaction of tetrachloroaurate-(III) with luminol In reversed micellar system of hexadecyltrlmethylammonlum chloride-water (buffered with sodium carbonate)-6:S (v/v) chloroform-cyclohexane was studied and applied to develop a new flow Injection procedure for the determination of gold at trace levels In chloroform.The behavior of the gold(III) complex was examined by Its spectral measurements In the near-UV and visible regions In dWferent media. All the optimization conditions for the method were determined by using a flow system, and the characteristics of the CL system In the reverse micelles were examined. The method Is simple and reproducible with a detection limit (DL) of 10 pg mL"1. The calibration graph was linear between 1 ng mL"1 and 1000 ng mL'1 along with a second straight Une from the DL up to 1 ng mL"1. The relative standard deviation was 3%.

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