Current status and trends in sensitivity improvement of elemental analyses of XRF spectrometry

A brief overview of the progressive development of x-ray spectroscopy (XRS) is described. Elemental analysis using x-ray fluorescence (XRF) spectroscopy and its geological, environmental, biological, medical, soil, water sediments and modern high-tech materials in terms of progress in power of detection, sensitivity, reliability, accuracy and cost have been discussed. Current status of least limits of detection (LLDs) and modern trends for the sensitivity improvement have been reviewed. These modern trends in XRF have clearly demonstrated its versatility as an analytical tool. The conventional WDXRF and EDXRF, their advantages and limitations and progress in detection process through improved reflection crystals like layered synthetic microstructure (LSMs), windows like ultra thin windows (UTWs), high resolution detectors like Si(Li), HPGe and the improved software and computer applications using various algorithms has been discussed. Better excitation conditions and new x-ray sources have resulted in total reflection XRF(TRXRF) and synchrotrons radiation XRF (SRXRF). These developments have extended LLDs from 10/sup -8/g to 10/sup -9/g routinely and 10/sup -12/g especially, when combined with the routine chemical manipulations of the other competitive spectroscopic techniques like AAS, ICP, NAA, with projections of microscopic analyses down to 10/sup -18/g, taking its applications to EXAFS and XANES area as a supplementary technique. Detection of lower Z number elements still remains the limitation however low energy x-rays from LASER plasma source and x-ray LASERS may be a solution to this limitation in future. (author) 11 tabs; 18 figs.; 41 refs