牛磺酸中主要成分含量检测方案(自动电位滴定)

APAT-0174en京都電子工業株式会社KYOTO ELECTRONICSMANUFACTURING CO.，LTD. APAT-0174en Application NoteDetermination of taurine Industry Pharmaceutical Instrument Automatic potentiometric titrator Measurement method Potentiometric titration /Neutralization titration Standards Japanese Pharmacopoeia 1.Scope This Application Note describes an example of quantifying taurine (2-aminoethanesulfonic acid)using the method prescribed in the Japanese Pharmacopoeia. Taurine is a zwitterionic compound with an amino group (-NH2) and a sulfo group (-SO3H) in themolecule.The charge of a zwitterion changes with the pH， so it cannot be titrated as is. However，if formaldehyde is added， it acts on the amino group as shown below， and only the sulfo groupremains. Accordingly， a solution formed by dissociation of the sulfo group will acidulate and can then betitrated with a base. 2.Precautions Formaldehyde reagents have an irritating odor and are extremely toxic to humans， so when performingthe actual measurement， place the measuring instrument in a local exhaust system. 3. Post-measurement procedure When storing the electrode， seal the electrolyte filling port in the comparison electrode with arubber stopper. The performance of the glass electrodes quickly deteriorates if they are stored while dry.Thefollowing storage methods are recommendedd. ·Short-term storage (less than one month)： Store in pure water. · Long-term storage (one month or longer)： Store in a mixture ofequal amounts (by volume ratio)of a pH 4 standard solution and a 3.3 mol/L aqueous potassium chloride solution. 4. Apparatus Main unit Automatic potentiometric titrator (preamplifier STD) Electrode .Combined glass electrode (Internal solutionn33.3 mol/L potassium chloridesolution) 5.Reagents Titrant 0.1 mol/L sodium hydroxide solution Additional reagents 36 to 38 % formaldehyde solution (a special class of reagent in accordance with JIS K 8872) 6. Procedure 1) Introduce approximately 0.2 g of the sample into a beaker， and weigh it. 2) Add 50 mL of pure water， and dissolve the sample. 3)Add 5 mL of a formaldehyde solution. 4) Titrate with a 0.1 mol/L aqueous sodium hydroxide solution.Note： In addition， perform a blank test under the same conditions， and correct the titrationvolume during sample measurement. 7. Calculation Purity of taurine (%)=(EP1-BL1)×TF×C1×K1/S EP1 Titration volume (mL) BL1 Titration volume (mL) for a blank test=0.0389 Titrant factor=0.9857 S Concentration conversion coefficient = 12.52 mg/mL Unit conversion coefficient =0.1 Weight of sample introduced (g) 8.Example (The above condition is an example. The setting condition depends on the model.) 京都电子工业株式会社-可睦电子(上海)商贸有限公司电话：021-54488867 电邮： kemu-kem@163.com - Example of titration curve- -Measurement results一 Taurine Sample (g) Titration (mL) Taurine(%) 1 0.2021 16.4497 100.17 2 0.2031 16.5036 100.01 3 0.2062 16.7675 100.08 Average - 100.09 SD - 0.08 RSD (%) - - 0.08 京都电子工业株式会社-可睦电子(上海)商贸有限公司电话：021-54488867 电邮： kemu-kem@163.com 都電子工業株式会社KYOTO ELECTRONICSMANUFACTURING CO.，LTD. 牛磺酸含量测定 应用资料(英文版)根据中国药典2020年版，牛磺酸【含量测定】取本品约0.2g，精密称定，加水50ml溶解，精密加入中性甲醛溶液（取甲醛溶液，滴加酚酞指示剂5滴，用0.1mol/L的氢氧化钠溶液调节至溶液显微粉红色）5ml，照电位滴定法（通则0701），用氢氧化钠滴定液（0.1mol/L）滴定。每1ml氢氧化钠滴定液（0.1mol/L）相当于12.52mg的C2H7NO3S。