Simultaneous multielemental determination using a low-resolution inductively coupled plasma spectrometer/diode array detection system

Abstract This work presents a versatile method for simultaneous multielemental analysis using detection with photodiode arrays and multivariate calibration techniques. A multidetection system based on an array of 1024 photodiodes was built and adapted to a commercial plasma emission scanning spectrometer. Spectral data were acquired at low resolution, allowing simultaneous monitoring of a broad spectral range and resulting in very informative but considerably overlapped spectra. Partial least squares and principal component regressions were employed to minimize overlapping problems. A numerical procedure for window selection was also developed. The new method was applied to the simultaneous determination of manganese, molybdenum, nickel, chromium and iron in steel samples, 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 systems and separate univariate calibrations, but the new method allows simultaneous determination of the five elements, with data acquisition significantly faster than in scanning instruments.