Abstract
Seven typical commercial energy dispersion x-ray analyzers were evaluated for application to the measurement of elemental concentration in polluted water. Sensitivity and detection limits were measured on single- (or dual-) element standards. Results for 400-sec counting intervals indicate that the better energy dispersive analyzers have limits of detection between 10 and a few hundred µg/cm2. Many pollutants in natural water are present at >10 ppb, which means that adequate material can be obtained from 100 to 1000 ml samples; some elements of interest such as Cd and Sn are generally present at <1 ppb, which makes practical detection marginal for the energy dispersion method. When x-ray calibration curves were prepared from individual-element gravimetric standards and used to analyze multiple-element samples (also prepared gravimetrically), the agreement between x-ray and gravimetric results showed an average relative deviation of 16%.
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