壳聚糖富集-火焰原子吸收法测定痕量银

研究了天然高分子吸附剂壳聚糖对银离子的吸附行为以及在不同pH值、干扰离子存在时对壳聚糖吸附银离子的影响,通过选择最佳吸附条件,建立了壳聚糖富集火焰原子吸收法测定银的方法。当溶液pH60、流速为1mL·min-1时,吸附率最高,达967%,静态饱和吸附量为978mg·g-1。用1mol·L-1H2SO4作为洗脱剂,洗脱效果最好。壳聚糖不吸附K+,Na+,Ca2+,Mg2+,Mn2+,富集时可与被测银离子分离,不干扰测定。100mg·mL-1的Al3+,Cr3+,80mg·mL-1的Ni2+,Cu2+,Pb2+,Zn2+虽然可被壳聚糖吸附,但不干扰测定。用此方法对实验室含银(183μg·mL-1)废水中的Ag进行测定,回收率为943%。

Determination of Trace Silver by Flame Atomic Absorption Spectrometry Using Chitosan Enriching Method

A method for the determination of trace silver by flame atomic absorption spectrometry using chitosan enriching method has been investigated. The conditions that influence the adsorption of silver by chitosan were studied. The optimal flow rate of the sample solution was 1 mL x min(-1), and the optimal sorption (96.7%) was possible by using the systems with pH 6.0 for silver. The amount of saturated adsorption of silver in the chitosan was 97.8 mg x g(-1). Silver was eluted from the chitosan by 1 mol x L(-1) H2SO4. 100 mg x mL(-1) of Al3+, Cr3+ and 80 mg x mL(-1) of Ni2+, Cu2+, Pb2+ and Zn2+ did not disturb the determination of silver. K+, Na+, Ca2+, Mg2+ and Mn2+ did not disturb the determination of silver because they were not adsorbed by chitosan. The method has been applied to the determination of silver (1.83 microg x mL(-1)) in waste water sample with a recovery of 94.3%.