ABSTRACT
Objective:To establish a high performance liquid chromatographic（HPLC） quantitative method for the determination of polyaminopropyl biguanide（PAPB） in cosmetics. Methods:Different forms of cosmetic samples were prepared by ultrasonic extraction and followed by high speed centrifugation of the extraction solution. The supernatant was degreased by hexane， and then was filtered by 0.22 μm millipore filter. The continued filtrate was taken for analysis. An Agilent reversed phase column， Zorbax SB-C18（5 μm，4.6 mm×250 mm）was used with 0.02 mol/L ammonium acetate buffer （pH=4.8） ： methanol （60∶40） as the mobile phase under the condition of isocratic elution. Diode array detection method was used for PAPB determination. Qualitative and quantitative determination of PAPB was conducted in 51 batches of commercially available cosmetics. Results:The relative standard deviations （RSD） were in the range of 1.2 %-4.4 %（n=6）； the recoveries were in the range of 97.5 %-106.5 %.The method showed a good linearity within the concentration range of 5-1 000 μg/mL with correlation coefficient of 0.999 62； The detection limit was 15 mg/kg. In 51 batches of commercially available cosmetics. One batch of makeup remover showed positive resullt， which was consistent with the UV spectrum of the standard. Conclusion:We have established a HPLC method for accurate quantification of PAPB. It can be used for analyzing the cosmetics products.
ABSTRACT
This paper aims to establish a method for the determination of sulfur dioxide in sulfur fumigation Chinese herbs. Sample powder and hydrochloric acid solution were isolated by paraffin layer in order to avoid early reactions, with the generation of sulfur dioxide, headspace with airtight needle was used to transfer sulfur dioxide into gas chromatograph, and detected with thermal conductivity detector. The analytical performance was demonstrated by the analysis of 12 herbs, spiked at four concentration levels. In general, the recoveries ranging from 70% to 110%, with relative standard deviations (RSDs) within 15%, were obtained. The limit of detection (LOD) was below 10 mg x kg(-1). Standard addition can be used for low recovery samples. The method is simple, less time-consuming, specific and sensitive. Methods comparison revealed that gas chromatography is better than traditional titration in terms of method operability, accuracy and specificity, showing good application value.