Multielement atomic absorption analysis using Hadamard transform spectroscopy with a new computation and superposition procedure

The application of Hadamard transform spectroscopy (HTS) to analytical atomic spectroscopy has been investigated. A theoretical examination of the signal to noise ratio indicates that HTS offers a slight multiplex advantage over single slit scanning of the spectrum for the measurement of intense lines, as in atomic absorption, but is disadvantageous for measuring small signals in atomic emission and fluorescence. Using a simple HT spectrometer Mg and Pb were determined simultaneously by flame atomic absorption spectrometry. Sensitivities similar to those of conventional systems were obtained but, owing to instrumental imperfections and a short data collection time, detection limits were worse. Optimum system performance was obtained when the mask interval width was equal to the width of the image of the spectrometer entrance slit. Greater spectral detail was revealed by superposition of a set of computed spectra in which the starting point of each spectrum was displaced from the others by a distance less than the interval width of the Hadamard mask. This approach gave improved spectra without increased instrumental complexity.