顺序注射-气体扩散分光光度法测定环境水中无机碳和有机碳

Gas diffusion separation-sequential injection spectrophotometry for the determination of inorganic and organic carbon in environmental water samples

提出了一个测定环境水中无机碳（IC）、有机碳（TOC）含量的顺序注射气体扩散光度分析方法。在线气体扩散分离二氧化碳后,分别测定总碳（TC）和无机碳的含量,利用其差值求出有机碳的含量,确立了最佳实验条件。通过在H2SO4试剂中添加5×10-3mol/LKMnO4来消除SO2和H2S的干扰。碳量在5~120μg/mL范围内与吸光度呈良好的线性关系,方法的检出限为2.9μg/mL。对含碳40μg/mL的标准溶液平行测定11次,相对标准偏差（RSD）小于1%。测定一个试样仅需要0.1 mL酸和0.2 mL指示剂,显著地降低了试剂的消耗。方法用于环境水中碳的测定,回收率在92.8%~107.2%之间。

A sequential injection spectrophotometric system with gas diffusion on-line separation was developed for the determination of inorganic and organic carbon in environmental water samples. After the contents of total carbon （TC） and inorganic carbon （IC） were determined, the content of organic carbon （TOC） can be obtained by the difference of them. The experimental parameters were opti- mized. The interferences from SO2 and H2S were effectively eliminated by addition of 5 X 10 3 mol/L KMnO4 in 0.2 mol/L H2SO4. A good linear relationship between the carbon content and absorbance was in the concentration range from 5 to 120μg/mL cabon. The detection limit was 2.9 μg/mL for carbon, and a relative standard deviation of 0.97% at concentration level of 40 μg/mL carbon were obtained. Only 0.1 mL acid and 0.2 mL indicator solution were used to determine a sample, which decreased greatly the consumption of reagents. The proposed method was successfully applied to the determination of carbon in environmental water samples with the recovery of 92.8%-107.2%.