[Analysis of Helindone Pink CN and Permaton Red in cheek rouge]

Analytical methods for red tar colors, Helindone Pink CN (R226) and Permaton Red (R228), in cheek rouge were developed. R226 and R228 were extracted from cheek rouge with chloroform by ultrasonication. After centrifugation, the supernatant was collected for the determination of R226 and R228. Methanol was then added to the residue for the extraction of Pigment Red 57-1 (R201) and Pigment Red 57 (R202). Each R226 and R228 was separately detected by the silica-gel thin-layer chromatography using the mixture of hexane and chloroform (2:1) or (3:1), or hexane and tetrahydrofuran (THF) (2:1) as a developing solvent. For the determination of R226 and R228, the extract in chloroform was injected into the HPLC equipped with Amide colomn and UV-VIS detector (detection wavelength 535 nm and 487 nm) using the mixture of hexane and THF as mobile phase. The linearity was obtained between the peak areas and the concentrations of R226 and R228 in the range of 0.625-10 microg/ml. R201 and R202 were determined using ODS column and the mixture of acetonitrile and phosphate buffer as mobile phase. Seven cheek rouge samples were analyzed. The red tar colors listed in each cheek rouge were contained in the range of 247 to 6574 microg/g.