Determination of sunset yellow in multi-vitamin tablets by photoacoustic spectroscopy and a comparison with alternative methods.

Photoacoustic (PA) spectroscopy in the visible wavelength region was shown to be suitable for a direct (no preparatory steps involved) quantification of sunset yellow (E110) colour in effervescent multi-vitamin tablets. Measurements on powdered tablets containing E110 were performed at 480 nm at which wavelength this synthetic colour shows appreciable absorbance. The PA data obtained were compared to the results acquired by diffuse reflectance spectroscopy and conventional spectrophotometry. Intrinsic simplicity, ease of sampling and rapid response were the most important advantages of the PA technique. In terms of sensitivity the performance of the three methods were comparable.