Use of a Spectrally Segmented Photodiode-Array Spectrometer for Inductively Coupled Plasma Atomic Emission Spectroscopy

The utility of a spectrally segmented photodiode array spectrometer was examined by using inductively coupled plasma atomic emission spectrometry ICP-AES. The spectrometer used in this study is capable of high resolution reciprocal linear dispersion of approximately 0.08 nmmm at 300 nm over a wide spectral range 190-145nm. The effect of using spectral-peak areas instead of peak heights as a signal definition was determined by using the emission signals from 10 molybdenum lines obtained at various photodiode array integration periods. In addition, a signal definition involving a summation over a range of 5 pixels offered the best signal-to-noise ratio when the noise was defined as the standard deviation of the residual values from the line fit to the sideband background level. A detection limit of 6ngml was determined in this way for molybdenum. The multichannel capability of the spectrometer was found to permit continuous background correction, thereby reducing errors caused by low- frequency noise or plasma drift. Detector linearity was found to extend over three orders of magnitude with a single integration period. Inductively coupled plasma, Photodiode array spectrometer, Multielement analysis.