TOTAL-REFLECTION X-RAY-FLUORESCENCE ANALYSIS UNDER VARIOUS EXPERIMENTAL CONDITIONS

Total reflection x-ray fluorescence (TXRF) is a well established analy tical technique which excels in the determination of trace elements in liquid samples with extremely low detection limits, In TXRF analysis, the use of different techniques to modify the excitation energy spect rum and to collimate the x-ray beams has been reported in the past, Al l these techniques require that the alignment of the TXRF set-up is op timized in order to obtain the maximum ratio between fluorescence sign als and background, i,e., the lowest detection limit, Owing to the fac t that total reflection conditions demand very small incident angles ( a few mrad), the alignment of the spectrometer and further optimizatio n of the geometry proved to be difficult and time consuming, In order to overcome these difficulties, a TXRF spectrometer with computer-assi sted control of the reflector position which is capable of being confi gured for different experimental conditions was constructed. In this p aper, the spectrometer was used to compare the effect that different s pectrum modification techniques have on the sensitivity and detection limits of different intermediate-Z elements. (C) 1997 by John Wiley & Sons, Ltd.