Determination of thiourea by terbium (III)/ prulifloxacin sensitized potassium permanganate-sulfite chemiluminescence with quenching method

Based on the thiourea quenching of the chemiluminescence of Tb 3+ / prulifloxacin (PUFX) sensitized KMnO 4 -Na 2 SO 3 system, a convenient and rapid chemiluminescence method for the determination of thiourea was proposed. The reaction between KMnO 4 and Na 2 SO 3 brought only weak chemiluminescence, but the chemiluminescence increased sharply in the presence of sensitizer Tb 3+ / PUFX. Addition of thiourea can prevent the reaction between KMnO 4 and Na 2 SO 3 , thus the chemiluminescence intensity was significantly decreased. Under the optimum conditions, the calibration graphs for thiourea were linear in the range of 1.0 × 10 -7 to 4.0 × 10 -5 mol•L -1 . The limit of detection was 6.4 × 10 -8 mol•L -1 . The method was applied satisfactorily to the determination of thiourea in tap water, lake water and rice noodles and the spiked recoveries were between 104.7 ~ 113.4%. The possible mechanism of sensitization and quenching was also proposed.