Cloud Point Extraction - Spectrometry Determination Of Cosmetics In The Form Of Chromium

Cloud point extraction is a kind of liquid-liquid extraction technology developed in recent years. The theoretical basis of the technology is the solubilization of the surfactant and the cloud point phenomenon. The measured material and complexing agent formed to complex, then the complex will be extracted to the surfactant phase sperated from water phase. Cloud point extraction has the advantages of low pollution, easy and simple to handle and so on. It can couple with most of analytical instrument, and has been already applied to the determination of the metal ion, the noxious substance in environment and the bioanalysis.Although flame atomic absorption spectrometry and inductively coupled plasma-atomic emission spectrometry have been widely used in the determination of the elements, the requirements for the analysis results become higher and higher in the research work, the complexity and diversity of the samples are increasingly at the same time, so directly analyzed by the two methods were already cannot satisfy the needs of work。But use cloud point extraction as a preconcentration method can make the detect limit lower and more suitable for the determination of elements.The aim of the paper is to enrich chromium by cloud point extraction, and then determined by flame atomic absorption spectrometry and inductively coupled plasma-atomic emission spectrometry, establish a new method for the determination of chromium in cosmetic samples. It's main content are as follows:Using Triton X-114 as surfactant and ammonium pyrrolidine dithiocarbamate(APDC) as complexing agent of hexavalent chromium, discussed the major facts such as pH, Triton X-114 dosage, APDC dosage, equilibrium temperature and so on by the FAAS. The result shows that: the optimum condition is pH 4.5,0.5mL 3%APDC, 1.0mL 1% Triton X-114. equilibrium temperature 50℃. Under this optimum condition, the limit of detection was 0.026mg/L and relative standard deviation was 1.52%. cosmetic samples were analyzed by the proposed procedure and the spiked relative recoveries were above 90%. Using Triton X-114 as surfactant and 8-Hydroxyquinoline(8-HQ) as complexing agent, researched pH, Triton X-114 dosage,8-HQ dosage, centrifuge time and other majors which affected the cloud point extraction rate of the trivalent chromium by ICP-AES. The result shows that:the optimum condition is pH 9,0.5mL 3%APDC,1.0mL 1% Triton X-114,equilibrium temperature 60℃. Under this optimum condition, the limit of detection was 0.50μg/L and relative standard deviation was 2.88%. Cosmetic samples were analyzed by the proposed procedure and the spiked relative recoveries were above 80%.