Determination of uranium in tin tailings using 4-(2-pyridylazo) resorcinol by flow-injection analysis

A flow-injection determination of uranium in tin tailings has been proposed. The method is based on complex formation of UVI with 4-(2-pyridylazo)resorcinol (PAR). A solution containing uranium(VI) is injected into merged streams of triethanolamine buffer and PAR-CDTA-sulfosalicylic acid solution. The coloured product is monitored at 530 nm. The method has been applied to tin tailing samples digested with HF-HNO3. The detection limit is 0.28 mg U l−1. A sampling rate of 180 h−1 and an RSD of 3.5% (at 5 mg U l−1, n = 12) are obtained.