SIMULTANEOUS MULTIELEMENTAL DETERMINATION USING A LOW-RESOLUTION INDUCTIVELY-COUPLED PLASMA SPECTROMETER DIODE-ARRAY DETECTION SYSTEM

This work presents a versatile method for simultaneous multielemental analysis using detection with photodiode arrays and multivariate calib ration techniques. A multidetection system based on an array of 1024 p hotodiodes was built and adapted to a commercial plasma emission scann ing spectrometer. Spectral data were acquired at low resolution, allow ing simultaneous monitoring of a broad spectral range and resulting in very informative but considerably overlapped spectra. Partial least s quares and principal component regressions were employed to minimize o verlapping problems. A numerical procedure for window selection was al so developed. The new method was applied to the simultaneous determina tion of manganese, molybdenum, nickel, chromium and iron in steel samp les, resulting in average relative prediction errors of 2.1% for Mn, 3 .4% for Mo, 0.6% for Cr, 1.5% for Ni and 0.8% for Fe. These errors are comparable to those observed with conventional scanning detection sys tems and separate univariate calibrations, but the new method allows s imultaneous determination of the five elements, with data acquisition significantly faster than in scanning instruments, (C) 1997 Elsevier S cience B.V.