The reaction between Pb^2＋ and xylenol orange （XO） was studied at pH 5.8 in HAc-NaAc buffer. It was sensitive and selective with the presence of sulfocarbamide and ammonium citrate. The new method named as primary-secondary wavelength spectrophotometry （PSWS） was applied instead of single-wavelength method for the determination of Pb based on the above-mentioned reaction. Results showed that such a method resulted in a good precision and high accuracy, the calculated curve was very stable. By analyzing several samples, the RSDs were less t...
