Study on Solid-Phase-Extraction Spectrophotometric Determination of Silver with p-Sulfobenzylidene-Rhodanine
WANG Lin1，HU Qiu-fen2，YANG Guang-yu2，YIN Jia-yuan2
1. The School of Chemistry and Bio-Science, Yunnan University for Nationalities，Kunming 650031，China 2. Department of Chemistry, Yunnan University, Kunming 650091，China
Abstract：The color reaction of silver with p-sulfobenzylidene-rhodanine (SBDR) was studied. Based on the color reaction of SBDR with silver (Ⅰ) and the solid phase extraction of its colored complex with Waters Porapak Sep-Park-C18 cartridge, a new method for the determination of micro-amount of silver (Ⅰ) was studied. In the presence of pH=2.8 citric acid-sodium hydroxide buffer solution and Tween-80 medium，SBDR can react with silver (Ⅰ) to form a stable 2∶1 complex. The colored complex can be extracted by C18 cartridge and eluted by ethanol (containing 5% acetic acid), and then can be determined by spectrophotometry. The molar absorptivity is 7.53×104 L·mol-1·cm-1 at 520 nm. Beer′s law is obeyed in the range of 0-1.2 μg·(25 mL)-1. This method can be applied to the determination of silver in water with satisfactory results.
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