Determination of 8 Pigments in Wall Material of Cigarette Capsules by High Performance Liquid Chromatography with a Novel Sample Vial for Extraction

Cigarettes of same batch were sampled as described in GB 5606.1-2004, and 0.200 0 to 0.300 0 g of the capsule shell, as stripped from the cigarette capsules in filter tips of each cigarette, was taken and placed into the outer case of the novel sample vial for extraction. 25 mL of water were added to the sample. The inner case of the extracting vial was then fixed at the mouth of the outer case with a sealing coil. The sample was extracted ultrasonically by keeping the extracting vial at 70 to 80℃ for 35 min. After cooling of the extracting vial to room temperature, the inner case was pressed downward to have the extract filtered though the dilter sieve plate, and the filtrate flowed out through the thin and curved tube in the inner case and was collected for use in HPLC analysis. Chromatographic separation of the 8 pigments in the sample was performed by using Waters XBridge C₁₈ column as stationary phase, and mixtures of 0.02 mol·L^-1 CH₃COONH₄ solution and methanol in various proportions as mobile phases in gradient elution. Diode array detector was used for detection. Tartrazine was detected at 427 nm, amaranth, cormine, sunset yellow, tempting red, acid red and red erythroplast were detected at 511 nm, and bright blue was detected at 625 nm. Linear relationships between values of mass concentrations of the 8 pigments and their corresponding peak areas were found in definite ranges, and the detection limits (3S/N) were in the range of 0.10 to 0.22 μg·g^-1. Values of recovery obtained by standard addition method ranged from 93.2% to 105%, and values of intra-day and inter-day RSDs (n=7) were all less than 5.0%.