镉离子印迹聚合物分离富集-火焰原子吸收光谱法测定痕量镉

利用沉淀聚合法制备了镉离子印迹聚合物,并用红外光谱仪和扫描电镜对其进行表征,测得其对镉的最大吸附量为36.10 mg/g。将印迹聚合物用于镉的分离富集,建立了镉离子印迹聚合物分离富集-火焰原子吸收光谱法(FAAS)测定痕量镉的方法。实验表明,用盐酸调节pH 值为5.5,控制上样流速为0.6 mL/min后,用10 mL水洗涤,控制洗脱液流速为1.0 mL/min,柱上吸附的镉可被10.0 mL 0.5 mol/L盐酸完全洗脱。采用FAAS测定洗脱液中的镉,镉质量浓度在0.50~60.0 μg/L范围内与吸光度呈良好的线性关系,线性相关系数为0.999 0。方法的检出限为0.18 μg/L。实验方法用于河水水样中镉的测定,测定值与原子荧光光谱法(AFS)基本一致,相对标准偏差(RSD,n=6)为1.6%～2.5%,加标回收率为95%~103%。

Determination of trace cadmium by flame atomic absorption spectrometry after separation and enrichment with cadmium ion imprinted polymer

The cadmium ion imprinted polymer was prepared by precipitation polymerization method, which was then characterized using infrared spectrometer and scanning electron microscopy. The saturated adsorption capacity was 36.10 mg/g. The prepared imprinted polymer was used for the separation and enrichment of cadmium. The determination method of trace cadmium by flame atomic absorption spectrometry (FAAS) was established after separation and enrichment with cadmium ion imprinted polymer. The pH was adjusted to 5.5 with hydrochloric acid. The sample flow rate was controlled at 0.6 mL/min. After washing with 10 mL of water, the cadmium adsorbed on column could be fully eluted with 10.0 mL of 0.5 mol/L hydrochloric acid. The flow rate of eluting solution was controlled at 1.0 mL/min. The content of cadmium in eluant was determined by FAAS. The mass concentration of cadmium in range of 0.50-60.0 μg/L showed good linearity to the absorbance, and the linear correlation coefficient was 0.999 0. The detection limit was 0.18 μg/L. The proposed method was applied to the determination of cadmium in river samples. The determination results were consistent with those obtained by atomic fluorescence spectrometry (AFS). The relative standard deviations (RSD, n=6) were between 1.6% and 2.5%. The recoveries were between 95% and 103%.