Determination of uranium in water samples with chromogenic reagent 4-(2-thiazolylazo) resorcinol after ionic liquid based dispersive liquid liquid microextraction

A simple extraction and spectrophotometric determination of trace amount of uranium was described. The method is based on complex formation between uranium and 4-(2-thiazolylazo)resorcinol (TAR), a well known ligand, C₉H₇N₃O₂S, and preconcentration of formed complex into a room temperature ionic liquid (RTIL), 1-methyl-3-octylimidazolium hexafluorophosphate. Under optimum conditions, the method is linear in the range of 7.14-1429 μg L^-1, and ₃S_b/m value was calculated as 0.26 μg L^-1. The method was applied to uranium spiked water samples. To the best of knowledge, the use of TAR as chromogenic agent with 1-methyl-3-octylimidazolium hexafluorophosphate as extractive medium is the first for the versatile determination of uranium. The accuracy of the method was confirmed with certified reference material (TM 28.3 fortified water). (author)