负载纳米二氧化钛分离富集-火焰原子吸收光谱法测定痕量金的研究与应用

Determination of Trace Gold by Flame Atomic Absorption Spectrometry after Separation and Preconcentration with Load Nanometer Titanium Dioxide

报道了负载对二甲胺基苯亚甲基若丹宁(DMABR)的纳米二氧化钛分离富集-火焰原子吸收光谱法(FAAS)测定痕量金的新方法。该方法具有操作简便、线性关系良好,灵敏度高和精密度高等优点。在动态条件下系统地研究了溶液pH值、流速、洗脱条件和干扰离子对痕量金分离富集的影响。结果表明,在pH为3.5时样品溶液以0.6mL.min-1流速过柱,金可被负载纳米二氧化钛定量富集。吸附的金可用0.1mol.L-1HCl-0.5mol.L-1硫脲以0.5mL.min-1流速完全洗脱。在优化的实验条件下,负载纳米二氧化钛对金的动态吸附容量为23.19mg.g-1。线性范围为0～0.40μg.mL-1,r=0.9993,检出限(3σ,n=11)为2.34ng.mL-1,相对标准偏差(RSD%)为2.9%(n=6,c=0.10μg.mL-1),加标回收率在96.7%～101.7%之间。方法用于实际水样中痕量金的测定,结果满意。

A new method for the determination of trace gold by flame atomic absorption spectrometry （FAAS） after preconcentration with p-dimethylaminobenzylidenerhodanine （DMABR） loaded with nanometer TiO2 was developed. The method is convenient, highly precise and linear in a wide range. Under dynamic condition, the optimum pH of solution, flow rate, elution conditions were obtained for preconcentration of trace gold. And the effect of interfering ions was also investigated. It was found that the studied gold could be quantitatively preconcentrated on loaded nanometer TiO2 at pH=3. 5, and the flow rate of sample solution was 0. 6 mL· min^-1 , and the flow rate of eluting solution with 0. 1 mol· L^-1 HCl-0. 5 mol·L^-1 thiourea was 0. 5 mL·min^-1 , sufficient for complete elution. The dynamic adsorption capacity of gold on load nanometer TiO2 was 23. 19 mg·g^-1. The linear range for gold was 0-0. 40 μg ·mL^-1, correlation coefficient was 0. 999 3, detection limit（3σ, n= 11） for gold was 2. 34 ng·mL^-1 , and the relative standard deviation was 2. 9% （n=6, c=0. 10 μg· mL^-1 ）, the recovery was in the range of 96. 7%-101.7%. The method has been applied to the determination of trace gold in water samples with satisfactory results.