Phosphine depression of calcium in flame atomic emission spectrometry with a uniform droplet generator

Abstract

The PHa depression of Ca emission signals Is the result of a condensed phase vaporization Interference. The combustion products of PH3, POx, diffuse Into the desolvatlng droplet to form a refractory Ca-POx compound. Through the study of flame emission profiles of vaporized, uniformly sized droplets, the formation of the refractory compound Is not observed to slow the free atom supply rate. The use of La3+ In the analyte matrix alleviates the depression. Aspirating H3P04 acid into the flame and Injecting the analyte Into a PH3 free flame results In a depression of the Ca emission similar to that of PH3. This similarity suggests the PH3 and P043" depressions of Ca emission signals In alr/C2H2 flames are the same.