THE PERFORMANCE OF A NEW LABORATORY-CONSTRUCTED CATHODIC-SPUTTERING ATOMIZER IN ATOMIC-ABSORPTION SPECTROMETRY

The performance characteristics of a laboratory-constructed cathodic sputtering atomizer for atomic absorption spectrometry have been evaluated. The new of argon flow rate and pressure, whereas the only cathocic-sputtering atomizer comercially available for atomic absorption spectrometry (Atomsource, manufactured by Analyte Corporation) does not. Our results follow the model of consecutive, first-order reactions: [GRAPHICS] where A is the analyte atom that has not yet entered the analysis volume of the atomizer, B is the analyte atom that absorbs and C is the analyte atom that is removed from the analysis volume, and k1 and k2 are first order rate constants. The importance of independent control of argon flow rate and pressure is shown by the increase in the k1/k2 ratio for Ag for the new atomizer compared to that for the Atomsource. The peak height sensitivity of the new atomizer is up to a factor of 5 better than that of the Atomsource, which does not allow independent control of argon flow rate and pressure. Also, the value of k2 for the new atomizer has been decreased, the result is a peak area sensitivity for the new atomizer that is 1-2 orders of magnitude better than that of the Atomsource. A parametric evaluation of the new atomizer has shown that most of the improvement in peak area sensitivity results from the increased residence time of the analyte atoms. A comparison of the sensitivity of the new atomizer with the sensitivity of the Atomsource has been made using both peak height and peak area absorbance.