Spectrophotometric determination of trace aluminum in water with xylenol orange based on sensitivity-enhancing effect of Tween 20

The sensitivity-enhancing effect of Tween 20 on the color reaction of xylenol orange(XO) with copper was studied to establish a novel spectrophotometric determination method of trace aluminium in water.The results showed that a stable colored complex was formed by the reaction among Al,XO and Tween 20 in HAc-NaAc buffer solution.The maximum absorption wavelength of this complex was at 510 nm and the apparent molar absorptivity was 2.63×104 L·mol-1·cm-1.A good linear relationship was obtained between the absorbance and concentration of Al in the range of 0-0.64 μg/mL with the correlation coefficient of 0.998 7.The detection limit was 0.007 7 μg/mL.The proposed method has been applied to the determination of Al in tap water and river water samples.with the relative standard deviation(RSD) of 1.2 %-1.7 % and the recovery of 97 %-103 %.