An electrochemical enrichment procedure for the determination of heavy metals by total-reflection X-ray fluorescence spectroscopy

An electrolytic separation and enrichment technique was developed for the d etermination of trace elements by total-reflection X-ray fluorescence spect roscopy (TXRF). The elements of interest are electrodeposited out of the sa mple solution onto a solid, polished disc of pure niobium which is used as sample carrier for the TXRF measurement. The electrochemical deposition lea ds to a high enrichment of the analytes and at the same time to a removal o f the matrix. This results in substantially improved detection limits in th e lower picogram per gram region. The deposited elements ale directly measu red by TXRF without any further sample preparation step. The homogeneous th in layer of the analytes is an ideal sample form for TXRF, because scattere d radiation from the sample itself is minimized. The proposed sample prepar ation method is useful particularly for the analysis of heavy metals in liq uid samples with for TXRF disturbing matrices, e.g. sea water. (C) 1999 Els evier Science B.V. All rights reserved.