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Abstract
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In this work, a simple, unexpensive and environmentally friendly liquid – solid microextraction for preconcentration of orthophosphate from water samples has been presented using cetyltrimethylammonium bromide (CTAB) surfactant. At first, ammonium molybdate and ascorbic acid were used in acid medium to form a blue molybdenum phosphate complex with a maximum absorption of 680 nm. The effect of different parameters on the complex formation and the microextraction was investigated and optimized. Under optimal conditions, linear range was obtained 15-150 μg L-1 and 150-950 μg L-1 with a correlation coefficient of 0.985 and 0.988, respectively. Limit of detection was 12.8 μg L-1. The relative standard deviation for determination of 200 μg L-1 was 6.2 % for five replications. The interference of common cations and anions was investigated. The proposed method was successfully used to determine orthophosphate in different aqueous samples with satisfactory recovery ranged from 91 to 105%.
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