Hassan, M. J. M.; Al-Rubaiawi, M. S. F.
Article respectively. Then, 1.0 mL of urea 4% (w/v) was added under shaking. The solution was further left to stand for a few minutes. Then, 1.0, 1.5, 1.5 mL of β-naphthol, phenol, and resorcinol were added to CFT, CFX, and CFM, while 0.7 mol L-1 of KOH solution was added sequentially to the mixture, and diluted to the mark with double distilled water. The azo dye that formed was monitored at λmax 545, 500, and 515 nm respectively. General procedure of cloud point extraction for drugs ceftriaxone and cefotaxime -1 Aliquots of the standard CFT and CFX solutions containing 0.25 − 6.0 mg L were prepared from 1000 mg L-1, placed into calibrated centrifuge tubes and prepared using the previous procedure. Then, 1.0 mL of Triton X−114 10% v/v, 2.0 mL of HTAB, and 2.0 mL of Na2SO4 5% w/v were added, After that, the tubes were manually shaken for 3 min and then placed in a water bath at 60 °C for 50 minutes. After the separation was complete, the tubes were transported to the ice bath for 10 min to increase the viscosity of the cloudy layer of the drug, while the decanted aqueous phase and the still cloud layer remained in the bottom of the tubes. The solutions were diluted using 0.5 mL of absolute ethanol. The obtained solutions were then directly measured using a UV-Vis spectrophotometer at λmax 545, 500 nm against a reagent blank that was prepared in the same manner. RESULTS AND DISCUSSION Absorption spectra Pink-violet-, orange-, and red-colored chromophores were formed through the coupling of diazotized CFT, CFX, and CFM with β−naphthol, phenol, and resorcinol in an alkaline medium respectively. These azo dyes were obtained with a maximum absorbance under optimized conditions, and were recorded at the wavelengths of 545, 500, and 515 nm, respectively, against the reagent blank solution, which has all the same additions as the samples except the drugs. The spectra are shown in Figures 2a, 2b and 2c.
Figure 2a. Absorption spectrum for 50 mg L-1 CFT with the reagent against the reagent blank under optimum conditions.
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