New Method Study Of Micro-extraction-spectrophotometric Determinate Rhodamine B

In recent years, the cloud point extraction have been a new technology in the liquid-liquid micro-extraction extraction areas,Feature of the cloud point extraction that different from other liquid-liquid extraction is the use of which the solubility and cloud point phenomenon of the non-ionic surfactant micelles in aqueous solution. When temperature and other parameters are changed, the micellar solution will appear to cloud point phenomenon. Micelles that dispersed in the solution will condensate thus caused phase separation. Surfactant enrichment phase have lots of hydrophobic organic, as a first processing means of separation and enrichment, compared with other pre-enrichment means, the cloud point extraction has many advantages, such as higher extraction efficiency, operational procedures very simple, safe, economical and environmentally friendly, and easy to associated with some of the instruments. The most commonly used surfactant in cloud point extraction is Triton X-114and Triton X-110, although the amounts is not great, degradation products alkylphenols have some toxicity to the environment. Based on this consideration, in this test, the use of surfactant lauric alcohol400as extraction, compared with Triton X-114and Triton X-110, it is the basic non-toxic and tasteless, more green.Dispersive liquid-liquid microextraction is also a new micro-extraction technology.And have larger influence and in the field of micro-extraction. in the liquid-liquid microextraction, dispersants and micro litre upgread extractant was quickly injected into the sample solution, as the role of the dispersant, rely on the pressure generated by this very rapid injection, extractant in the sample solution form a large number of small beads. The target compound was quickly extracted into the extractant beads, which can greatly increase the extraction efficiency. and enrichment factor.Rhodamine B is a red synthetic dye, once,it had been used as a food additive, and later,some person discovery it is toxic and prohibit the use of. Study a kind of method which have features of simple, fast, sensitive and accurate to detect Rhodamine B in foods, has great significance。Taking into account the UV-visible spectrophotometry is simple, sensitive and accurate, and the instrument easy to get, is widely used, this study is based on micro-extraction technology, aimed at establishing spectrophotometric determination new method Rhodamine B. The main contents include:(1) mixed micelle-mediated cloud point extraction spectrophotometric detection Rhodamine B in foodRhodamine B existence as the cationic form in aqueous solution, has strong hydrophilic. Adding a certain amount of anionic surfactant, the two kinds matters form hydrophobic ion pair by the interaction of anion and cation, and were extracted into the non-ionic surfactant micelles, extraction efficiency will be greatly improved. Non-ionic surfactant lauric acid400and the anionic surfactant sodium dodecyl benzene sulfonate cloud point extraction of Rhodamine B in food using suitable conditions such as pH, surfactant dosage, of equilibration time and temperature, salt effect and the impact of coexisting ions has been systematically studied,establish mixed micelle-mediated cloud point extraction-spectrophotometric determination of Rhodamine B in food. Under the optimum conditions, the absorbance of Rhodamine B within10-650ng/mLhas the good linear relationship (r2=.9853), the detection limit is2.6ng/mL. The method had been successfully applied to the determination of Rhodamine B, the relative of recovery94.5～102%, relative standard deviation RSD was0.75%～2.75%(n=5).(2) dispersive liquid-liquid microextraction spectrophotometric determination of rhodamine B in foodwe detailed studied suitable conditions for ethanol as a dispersing agent, and methylene chloride as the extractant extract rhodamine B in food, Such as pH, type and dosage of dispersant, type and amount of extractant, centrifugation time, salt effect and the influence of coexisting ions. Establish a new method of dispersive liquid-liquid micro-extraction and spectrophotometric determination of rhodamine B in foods. The linear range of the method for the determination of rhodamine B is5-900ng/mL, the detection limit is2.5ng/mL, the method is applied to the determination of rhodamine B in the food, the recoveries of93.5～101%, relative standard deviation RSD was1.48%～2.39%.