【摘要】 基于硅胶表面对碱性体系中新生成的氧化银(Ag2O)的有效吸附,建立了流动注射-固相氧化物分离富集-火焰原子吸收法测定痕量银的方法.当银以氧化物的形式被滞留在硅胶固相表面时,硅胶表面的硅醇基和表面电荷有利于反应体系中新生成的Ag2O胶状沉淀的吸附,将收集的沉淀用HNO3(10%,体积分数)洗脱后用火焰原子吸收测定.当进样体积为5.4mL时,测得的富集系数为25.5,检出限为0.6μg/L,采样频率为50次/h,线性范围为2～150μg/L,相对标准偏差(RSD)为2.0%(40μg/L,n=11).将该法用于自来水、河水、井水、雪水和山泉水中银含量的测定,加标回收率分别为93.3%,89.5%,96.6%,108.4%和102.8%.更多还原

【Abstract】 A novel flow injection-solid phase oxide collection-flame atomic adsorption spectrometry(FAAS) was developed for the determination of trace silver in water samples using sodium hydroxide as precipitating reagent and silica beads as adsorbent.Silver was precipitated in form of oxide and then collected on solid phase surface of silica beads packed micro-column as oxide collector.The silanol groups and surface charges on the surface of silica beads contribute to precipitation adsorption of Ag2O.The precipitate was afterwards quantitatively eluted by 10%(volume fraction) nitric acid with the detection by FAAS.By loading 5.4 mL sample solution,an enrichment factor of 25.5,a detection limit(3σ) of 0.6 μg/L and a sampling frequency of 50 times/h were achieved,along with a linear range within 2—150 μg/L and a precision of 2.0% RSD at the 40 μg/L level(n =11).The present procedure was applied for the determination of silver by spiking recoveries in tap water,river water,well water,snow water and spring water,and the spiking recoveries were 93.3%,89.5%,96.6%,108.4% and 102.8%,respectively.更多还原