“…These methods require the separation and concentration of chromium by liquid-liquid extraction, [21][22][23][24] cloud point extraction to the surfactant-rich phase, [22][23][24][25][26][27] coprecipitation, 23 ion exchange 34 or ion-exchange chromatography, 35 organic soluble membrane lter, 40 sorption or solid phase extraction. 9,20,25,36,37,41,43 Spectrophotometry is the most commonly used method for determination of chromium(VI) in water samples. 6 Various organic reagents have been suggested for chromium(VI) determination including 1,5-diphenylcarbazide, [33][34][35][36][37] methyl orange in the presence of potassium bromate, 38 methyl blue in the presence of sodium periodate, 39 o-chlorophenyluorone and tetradecylpyridinium chloride, 40 1,4,8,11-tetraazacyclotetradecane (cyclam), 41 but the number of such reagents is limited.…”