Abstract:

A high performance liquid chromatographic （HPLC） method was developed for the determination of 47 kinds of dyestuffs in oxidative hair dye. The samples were extracted ultrasonically with anhydrous ethanol-10 g/L sodium bisulfite solution （7∶3）, and then 2 g/L sodium bisulfite solution was added to a constant volume of 25 mL. If necessary, the extractions were centrifuged at 10 000 r/min for 5 minutes. Chromatographic separation was carried on a Shim-pack GIST C₁₈ （4.6 mm×250 mm, 5 μm） column by gradient elution. Acetonitrile-20 mmol/L dipotassium hydrogen phosphate （pH7.5） and methanol-20 mmol/L dipotassium hydrogen phosphate （pH7.5） were used as the mobile phase, respectively. The flow rate was 1.0 mL/min and the column temperature was 25 ℃. The analysis of 47 kinds of dyestuffs was performed by HPLC with diode array detector at the wavelength of 230, 280 nm, respectively. Quantification analysis was performed by the calibration curve method. The linear ranges of 47 kinds of dyestuffs show good linearity with the correlation coefficients more than 0.999. The limits of detection （LOD） are in the ranges of 1-35 μg/g. The mean recoveries at three different concentration levels are 80.4%-110.7% with the RSDs of 0.25%-5.08%. Compared with the current standard, this method increases the determination of 15 permitted dyes. This method has high accuracy and precision, and can meet the actual detection needs. It is suitable for the determination of 47 kinds of dyestuffs in oxidized hair dyes.

Key words: high performance liquid chromatography, oxidized hair dyes, dyestuff, content determination