Ion-pair single-drop microextraction with ATR-FTIR determination of phosphate in water samples

A simple, rapid and green ion-pair single-drop microextraction procedure followed by attenuated total reflectance-Fourier transform infrared technique has been developed for the analysis of phosphate in water samples. This method is based on the extraction of the phosphate-cetyltrimethylammonium bromide ion-pair by the single drop extraction procedure. The linear range for calibration plot of phosphate is 1-900 ng mL(-1), with good correlation coefficient (r(2) = 0.998). The limit of detection, limit of quantification, standard deviation and relative standard deviation of six replicate measurements are respectively 0.34 ng mL(-1), 1.12 ng mL(-1), 0.001 and 0.94-3.36%. The significant parameters such as selection of solvent, their volume, ion-pair reagent and their concentration, extraction time, stirring rate, sample pH, extraction temperature and effect of salt concentration are studied and optimized. The present method is successfully applied for the quantification of phosphate in water samples with minimal solvent consumption and sensitivity as compared with the conventional methods.