Influence of sample bulk composition on the accuracy of semi-quantitative spectral analysis. The precision of the analysis is the sum of all random confounders; the correctness of the analysis is the systematic error. The effect of sample bulk composition on systematic error, i.e., correctness of analysis, is well known. The effect of sample bulk composition on the accuracy of spectral analysis, however, depends on the methodology, spectral setup, and other factors specific to a particular laboratory.