USE OF A SEGMENTED ARRAY CHARGE-COUPLED-DEVICE DETECTOR FOR CONTINUUMSOURCE ATOMIC-ABSORPTION SPECTROMETRY WITH GRAPHITE-FURNACE ATOMIZATION

A commercially available echelle spectrometer with a segmented array c harge coupled detector (SCD) was used with a xenon are lamp and graphi te furnace atomizer for continuum source atomic absorption spectrometr y (CS-AAS), Approximately 67% of the spectral wavelengths correspondin g to the resonance transitions used for routine AAS determinations wer e available on the SCD, As many as eight elements were determined simu ltaneously with a read frequency of 50 Hz for each array, The high lum inosity of the echelle and the high quantum efficiency SCD provided ph otoelectron levels that ranged from equivalent to 7 times higher than those previously measured by CS-AAS using a linear photodiode array (L PDA) detector, The low read noise of the SCD resulted in the absorbanc e measurements being limited by the photon shot noise of the continuum source, Detection limits were obtained that ranged from equivalent to a factor of 3 better than those previously obtained for CS-AAS and fr om a factor of 2 worse to a factor of 10 better than those for convent ional, line source AAS, Sensitivities, as determined by intrinsic mass (mass necessary for an absorbance of 0.0044 pm s), were similar to th ose measured previously with an LPDA, The high resolution of the echel le allowed detailed inspection of the spectra surrounding the waveleng th of the elements determined, Data were displayed using contour absor bance plots, Molecular peaks were observed within the spectral window of the sub-arrays fbr As (193.7 nm) and Se (196.0 nm), These peaks wer e spectrally and temporally resolved from the analyte peaks and disapp eared in the presence of a Pd chemical modifier, A low sensitivity Pd line was identified that was 15 pm from the Se line, The Pd and Se pea ks were resolved using a spectral bandwidth of 3 pm per pixel.