【摘要】 用TBP-棉纤维吸附实现铬(Ⅵ)与铬(Ⅲ)的在线分离富集,并用流动注射(FI)-火焰原子吸收光谱法(FAAS)分别测定其含量。将TBP-棉纤维小球填入自制的锥形柱并组装在FI系统中作为分离单元。将预先调至pH 0.75的样品溶液,以4mL·min-1流量注入FI系统中,并在锥形柱中富集分离160s。此时铬(Ⅵ)被TBP-棉纤维吸附,而铬(Ⅲ)随流出液流出。收集流出液测定铬(Ⅲ)量。用水以2.6mL·min-1流量过锥形柱洗脱铬(Ⅵ),洗脱液引入FAAS,测定铬(Ⅵ)含量。铬质量浓度在0.100~0.900mg·L-1以内呈线性。对与0.02μg铬(Ⅲ)共存的0.10μg铬(Ⅵ)溶液作7次测定,计算得到铬(Ⅵ)测定值的相对标准偏差为6.4%。添加0.500mg·L-1铬(Ⅵ)及0.100mg·L-1铬(Ⅲ)溶液,计算得到铬(Ⅵ)及铬(Ⅲ)的平均回收率依次为119%和107%。更多还原

【Abstract】 A method of FI-FAAS for simultaneous determination of Cr(Ⅵ)and Cr(Ⅲ)with on-line separation of Cr(Ⅵ)from Cr(Ⅲ)by adsorption on TBP-cotton fiber was proposed.A self-made conical column was used to pack the TBP-cotton fiber globes,and incorporated into the FI system as an on-line separation unit.The sample solution with its acidity at pH 0.75was injected into the FI-system at the flow-rate of 4mL·min-1 and separated(or enriched)in the conical column for 160s,having Cr(Ⅵ)adsorbed on TBP-cotton fiber,and Cr(Ⅲ)flowed out in the effluent which was collected and used for determination of Cr(Ⅲ).Cr(Ⅵ)adsorbed on the column was eluted with distilled water with a flow-rate of 2.6mL·min-1,and the eluate was introduced into FAAS for determination of Cr(Ⅵ).Linear relationship between values of absorbance and mass concentration of chromium was kept in the range of 0.100-0.900mg·L-1.Precision was tested by repetitive determinations of 0.10μg Cr(Ⅵ)in presence of 0.02μg Cr(Ⅲ),and value of RSD(n=7)found for Cr(Ⅵ)was 6.4%.Recovery was tested by analyzing mixed solutions containing 0.500mg·L-1 Cr(Ⅵ)and 0.100mg·L-1 Cr(Ⅲ),giving average recovery of 119%for Cr(Ⅵ),and of 107%for Cr(Ⅲ).更多还原