Spectrometric determination of chromium in FD&C blue no. 1 by X-ray fluorescence

An X-ray fluorescence spectrometry (XRF) method was developed and validated for determination of chromium in FD&C Blue No. 1. Results of this analysis were compared with those obtained with an atomic absorption spectroscopy (AAS) method currently used by the U.S. Food and Drug Administration. Levels of Cr, as determined by the XRF and AAS methods, were comparable. The limit of quantitation for the XRF method is 4 micrograms Cr/g. The predicted 95% confidence interval at the specification level is 50 +/- 5 micrograms/g.