天然水、饮用水、废水中苯氧羧酸除草剂检测方案(毛细管电泳仪)

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HIGH PERFORMANCECAPILLARYELECTROPHORESIS SYSTEMWWW.LUMEX.BIZ DETERMINATION OF PHENOXYCARBOXYLIC ACID HERBICIDES INWATER LUMEX Method M 01-34 (2007) INTRODUCTION The method allows determination of herbicides classified as phenoxycarboxylic acids， specifically： 2，4-dichloro--phenoxybutyric acid (2，4-DB)， 2，4-dichlorophenoxypropionic acid (2，4-DP， Dichlorprop)， 2，4-dichloropheno--xyacetic acid (2，4-D)， and phenoxyacetic acid in samples of natural， potable and treated waste water bycapillary electrophoresis. MEASUREMENT METHOD The capillary electrophoresis method for evaluation of 2，4-D class herbicides concentration is based on thedifferential migration and separation of these substances in the electric field due to their differentelectrophoretic mobility. Identification and quantitative determination of the analyzed components areperformed by detecting the inherent UV absorption at 205 nm wavelength. MEASUREMENTRANGE Ranges of measurable concentrations for analysed herbicides are 0.2-20 mg/L.If minimal concentrations should be detected (less than 0.2 mg/L)， the sample must be concentrated bysolid-phase extraction， in this case the range of detectable concentrations will be 0.002-0.2 mg/L for a 100-mL sample. Humic acids， if below 50 mg/L， do not influence determination of subject components. Analyzed herbicides are decomposed in aqueous media to form 2，4-dichlorophenol， which completelyseparates with subject components during analysis and does not influence their proper determination. EQUIPMENT AND REAGENTS The “CAPEL-105/105M”capillary electrophoresis system with high-voltage positive polarity is used inmeasurements. Data acquisition， collection， processing and output are performed using a personal computer running under“WINDOWS 2000/XP" operating system with installed dedicated software package for acquisition andprocessing of chromatography data. All reagents must be of analytical grade or better. EXAMPLE OF A REAL ANALYSIS Buffer： borate Capillary： LEFF/LTOTAL 50/60 cm， ID 75 pm Injection： 450 mbar x sec Voltage： + 25 kV 100 mAU Detection： 205 nm Sample： test solution 3 (20 mg/L of each compound) 1-2，4-dichlorophenoxybutyric acid 2-2，4-dichlorophenoxypropionic acid 3-2，4，5-trichlorophenoxyacetic acid 4-phenoxyacetic acid 2 3 4 5 6 min The contents on this paper are subject to change without notice.     LUMEX毛细管电泳法可测定天然水、饮用水和废水中的2,4-二氯-苯氧丁酸（2,4-DB），2,4-二氯苯氧丙酸（2,4-DP，二氯丙烷），2,4-二氯苯基-乙酸乙酯（2,4-D）和苯氧乙酸等除草剂。该法基于电场中不同物质的迁移和分离的不同在205 nm波长下检测紫外吸收来进行分析组分的鉴定和定量测定。