HPLC Determination of Chlorophyllin Copper Disodium and Chlorophyllin Copper Trisodium in Oral Cleaning Products

HPLC was applied to the determination of chlorophyllin copper disodium and chlorophyllin copper trisodium in oral cleaning products. The oral cleaning product sample (5.000 0 g) was mixed with 0.2 mol·L^-1 acetic acid-ammonium acetate buffer solution of pH 5.5 (20 mL), and then 5.0 g of adsorbent (polyamide) was added. After centrifugation, the precipitate was desorbed twice (10 mL each) with 20 mL of desorption solution (mixture of 0.1 mol·L^-1 NaOH solution and methanol with ratio of 1:10). The combined supernatant was evaporated to near dryness at 45℃ in the water bath. 1 mL of mobile phase A was added and then the solution was filtered on 0.22 μm organic microporous membrane. YMC Carotenoid C₃₀ chromatographic column was used as stationary phase, and the mixed solution of mixture (A) of methanol-water-formic acid (90+10+0.1) and mixture (B) of TBME-methanol-formic acid (100+10+0.1) mixed in different ratios was used as mobile phase in gradient elution. Detection at 405 nm was adopted in the determination. Linear relationships between values of peak area and mass concentration of chlorophyllin copper disodium and chlorophyllin copper trisodium were kept in the same range of 5.0-500.0 mg·L^-1, with same detection limit (3S/N) of 1.5 μg·kg^-1. On the base of blank sample, test for recovery was made by standard addition method; values of recovery found were in the range of 89.6%-98.4%, with RSDs (n=6) in the range of 1.4%-2.7%.