甲醇、2-丙醇、2-甲氧基乙醇、正己醇中水分含量检测方案(卡氏水分测定)

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HIITACHI1nspire the Next HIRANUMA APPLICATIONDATA Karl Fischer Titrator Data No. KF2 Water contents Alcohols 1.Abstract Water content of Alcohols is determined by Karl Fischer coulometric titrator. In coulometric titration， iodine of Karl Fischer reagent is generated by.electrolysis and generated iodine quantitatively reacts with water. Reaction formula is described below. Ho+I+ SO2+3RN+CH3OH→2RN·HI+RN·HSO4CH3 Alcohols do not interfere the Karl Fischer reaction and direct injection method could apply. Anode solution is selected in accordance with samplesolubility. General-use anode solution contains methanol as solvent. Alcohols with long carbon chain have low solubility in methanol. In that case， useof anode solution for oil is appropriate. When fritless cell is used， cathode solution is not necessary. 2. Apparatus and Reagents (1)Apparatus (2)Reagents Titrator：Karl Fischer Coulometric titratorElectrolytic cell：Standard CellAnode solution：Hydranal coulomat AG (for general use， nonhalogenated)Cathode solution：Hydranal coulomat CG 3. Procedure (1) Fill 100 mL of anode solution and one ampoule of cathode solution into the electrolytic cell as shown in Fig.3.1 (2) Start blanking to attain stable background. (3) Wash the syringe with sample. (4) Draw the sample into syringe and then weigh the syringe. (5) Inject sample from rubber septum of electrolytic cell as shown in Fig.3.2. (6) Start titration. Measurement parameter is shown in Table 4.1. (7) Weigh the syringe again and then set the difference of weight to sample size. Fig.3.1. Preparation of the reagents. Fig.3.2. Injection of sample. 4. Parameters and results Table 4.1. Parameters Condition File Cal Mode O：Sample weight(net) X-(H2O-BLANK)/SIZE Interval Time 20 sec Current SLOW S-Timer 0 min Blank Value 0 ug Unit Mode AUTO Auto Interval 0 g Minimum Count 5 ug Back Ground ON Sample Size Input Every Time Cell Type Standard/Fritless Sample Apparatus Cell Reagent Sample Size (g) Water (ug) Water Content Methanol AQ Standard AG 0.5988 672.9 1124 ppm CG 0.8890 991.6 1115 0.8710 973.6 1118 2-propanol AQ Standard AG 1.5078 138.9 92.1 ppm CG 1.6015 145.7 91.0 1.6574 152.6 92.1 2-methoxyethanol AQ Standard AG 0.86583 156.4 180.6 ppm CG 1.36865 243.5 177.9 0.83448 150.1 179.9 n-hexylalcohol AQ Standard AG 0.87698 132.1 150.6 ppm CG 0.92031 138.0 149.9 0.81105 124.0 152.9 5.Note (1) Use dried syringe and syringe vial in Fig.5.1， for preventive of contamination by atmospheric water. Put appropriate anode solution in use according to the solubility of the sample. For example， Hydranal Coulomat AG-H and Oil are suitable foroils. (2) Note ： these reagents does not correspond to Fritless cell. Fig.5.1. Draw the sample from syringe vial. Science for a better tomorrow Science fora better tomorrowL热线电话：日立科学仪器(北京)有限公司 本实验采用卡尔费休库仑滴定仪对醇中水含量进行测定。