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第3期
白海强等：环境样品酞酸酯测定中降低空白值方法的探讨
23
Study on Decreasing the Blank Value in Determining
Phthalate Esters for Environmental Samples
BAI Hai-qiang, LU Bao-yu, GUO Chen, LIAO Ping-de*, DENG Chao-bing
（Guangxi Environmental Monitoring Center Station, Nanning 530028, China）
Abstract: For all aspects of the analysis of phthalate esters in environmental samples are susceptible to the interference of pollution, such as glassware, solvent blank, blank of anhydrous sodium sulfate, the instrument blank, the entire blank etc, to do a careful check of the blank value. The results showed that: glassware cleaned by chromic acid lotion, solvent selected HPLC grade or redistilled analytical grade, anhydrous sodium sulfate using after high temperature drying, concentrated selection the water bath the natural evaporation or blowing by high-purity nitrogen, and other measures can greatly reduce the interference of the background blank value. And proposed control measures to reduce the interference of the blank value in order to reduce the risk of contamination in the determination process to ensure the accuracy and reliability of test results. Key words: environmental samples; determination of phthalate esters; blank value; contamination interference; control measures
（上接第17页）
Study on the Influencing Factors
of Total Nitrogen Determination in Water Quality Analysis
FANG Yi
（Department of Safety Technique and Environmental Engineering, Fujian Chuanzheng ＆ Communications College, Fuzhou 350007, China）
Abstract: In this paper, total nitrogen in water was determined by alkaline potassium persulfate digestion-ultraviolet spectrophotometric method. The influencing factors were discussed in detail. It was shown that the blank absorbance in the determination of total nitrogen is obviously influenced by the purity of reagent and the conserving time of alkaline potassium persulfate. Furthermore, the digestion time and the cooling time after digestion also affect the blank absorbance and relative error. Under the optimum conditions, the determining result was accurate and reliable.
Key words: total nitrogen; alkaline potassium persulfate digestion; ultraviolet spectrophotometric method; influencing factors