No abstract

Cloud point extraction methodology was successfully employed for preconcentration of trace amounts of amaranth prior to its determination by spectrophotometry. The method was based on the extraction of amaranth as an ion pair with tetrabutylammonium ion from aqueous solution using Triton X-100 as non-ionic surfactant. The extracted surfactant rich phase was diluted with ethanol and its absorbance was measured at 518 nm by a spectophotometer. An optimum set of surfactant concentration, pH, equilibration temperature and time, tetrabutylammonium hydrogen sulfate and salt concentration were obtained. The calibration graph was linear in the range of 20-1600 ng ml -1 of amaranth in the initial solution with r = 0.9993 (n = 12). Detection limit based on three times the standard deviation of the blank (3S b ) was 13.0 ng ml -1 (n = 10), and the relative standard deviation (R.S.D) for 100 and 1000 ng ml -1 of amaranth was 4.2 and 1.4% (n = 10), respectively. The proposed procedure was applied to the determination of amaranth in different food samples.

A surfactant mediated cloud point extraction (CPE) procedure has been developed to remove color from wastewater containing malachite green using Triton X-100 as non-ionic surfactant. The effects of the concentration of the surfactant, temperature and salt concentration on the different concentrations of dye have been studied and optimum conditions were obtained for the removal of malachite green. The concentration of malachite green in the dilute phase was measured using UV-Vis spectrophotometer. It was found that the separation of phases was complete and the recovery of malachite green was very effective in the presence of NaCl as an electrolyte. The results showed that up to 500 ppm of malachite green can quantitatively be removed ([95%) by CPE procedure in a single extraction using optimum conditions.