Solid phase extraction using silica gel modified with murexide for preconcentration of uranium (VI) ions from water samples.

Murexide was chemically bonded to silica gel surface immobilized 3-aminopropyl trimethoxysilane (APMS) to produce the new sorbent. A solid phase extraction method using the new sorbent has been developed to separate and concentrate trace amount of uranium (VI) from aqueous samples for the measurement by spectrophotometry method using Arsenazo III reagent. The influences of some analytical parameters on the quantitative recoveries of the analyte were investigated both in batch and column methods. Quantitative recovery of U(VI) was achieved by stripping with 0.1 mol L(-1) HCl. The maximum sorption capacity of the modified silica gel was 1.13 mmol g(-1) U(VI). A high preconcentration factor value of 400 with a lower limit of detection of 1 microg L(-1) was obtained for U(VI). The practical applicability of the developed sorbent was examined using synthetic and real samples such as sea/ground water samples.