2-(2-喹啉偶氮)-1,5-苯二酚光度法测定银的研究

STUDY ON THE PHOTOMETRIC DETERMINATION OF SILVER WITH 2-(2-QUINOLYLAZO)-1,5-DIHYDROXYBENZENE AS CHROMOGENIC REAGENT

研究了2 (2 喹啉偶氮) 1,5 苯二酚(QADHB)试剂与银的显色反应,在pH 5.0的柠檬酸氢氧化钠缓冲(内含0. 01 mol·L-1 的Na2EDTA)介质中,十二烷基磺酸钠(SDS)存在下,QADHB与银反应生成2∶1 稳定的络合物,λmax=550 nm,ε=6.56×104L·mol-1·cm-1。银含量在0~30μg/25 mL内符合比耳定律,方法用于环境水样中银含量的测定,结果满意。

In a citrate buffer medium of pH 5.0, and in the presence of sodium dodecyl sulfonate (SDS), 2-(2-quinolylazo)-1,5-dihydroxybenzene (abbreviated as QADHB) reacts with silver (Ⅰ) to form a stable coordination complex (R∶Ag=2∶1), having its Absorption maximum at 550 nm and its apparent molar Absorptivity of 6.56×10~4L·mol^(-1)·cm^(-1). In the buffer solution, EDTA (disodium salt) is added to have a concentration of 0 01 mol·L^(-1), acting as a masking agent. Beer′s law is obeyed in the concentration range of 0~30 μg of Ag(Ⅰ) in (25 mL) of solution. In its application to the determination of silver in industrial waste water and tap water, satisfactory results were obtained, which were in consistency with the results given by AAS method. RSD′s found were less than 3.5%, and recoveries obtained were in the range of 97%~102%.