检测维生素C（碘量法）

Application Application Application Use This method is used to determine the content of ascorbic acid (Vitamin C) with the lodine titrant in juices likeorange or apple juice. The sulfite (SO2) in the juice is masked before with glyoxal solution. Appliances Titrator： TL 6000/7000 (TL 6000/7000 M1/10) consists of Basic device Magnetic stirrer TM 235 10 mL Exchange unit WA 10， with brown glass bottle for titrant complete Electrodes ● Electrode： Pt 1200 or with cable L 1 NN Reagents Titration agent： lodine solution 0.01 mol/L Other reagents： H2SO4 25% and Glyoxal solution 40 % Description Preparation of the 0.01 mol/L lodine solution The iodine titrant is made out of 0.05 mol/l titrant solution which can made from ampuoles. Preparation of the Glyoxal solution A solution of 40 % Glyoxal is adjusted with NaOH to a pH value of 7.0 Preparation of the H2SO4 25% To 75 ml distilled water are carefully added 14 ml H2SO4 96 %(conc.) This mixture is filled up to 100 ml withdistilled water. Titration In a 100 or 150 mL beaker are added 50 ml sample and 2 ml of the Glyoxal solution. After 5 minutes 5 ml ofthe H2SO4 25% are added. The mixture is directly titrated with the lodine solution to an pA endpoint. Methods GLP documentation Titration graph 2.5pA0.846 ml Method name： Vitamin C with Iodine Titration duration： 1 m 12 s End date： 17.05.13 End time： 13：32：40 Titration data Sample ID： Granini 5 Pattern： 50.000 ml Start pA： -0.024 uA End pA： 3.046 pA EP： 0.846 ml/ 2.5 pA ASC： 101.31 mg/I Calculation formula ASC： (EP-B)*T*M*F1/(V*F2) Mol (M)： 176.10000 Blank value (B)： 0.0000 ml Titre (T)： 0.03400000(m) Factor 1 (F1)： 1000.0000 Pattern (V)： 50.000 ml (m) Factor2 (F2)： 1.0000 Statistics： Off Application sample titration (page 2)： Method data overall view Method name： Vitamin C with Iodine Created at： Method type： Automatic titration Last modification： Measured value： pA Titration mode： d-stop Documentation： GLP Linear steps： 0.020 ml Measuring speed/ drift： 1s Initial waiting time： O s Titration direction： Increase Pretitration： 0.100 ml Delay time： 04 s Endpoint： 2.5 pA delta endpoint： 2.0 pA Endpoint delay： 5s Polarization voltage： 100 mV Dosing parameter Dosing speed： 20.00% Filling speed： 30 s Maximum dosing volume： 4.00 ml Unit values Unit size： 05ml Unit ID： 1296649042 Reagent： Iod Batch ID： no Charge Concentration [mol/l]： 0.03400 Determined at： 10/17/12 22：53：39 Expire date： 12/05/11 Opened/compounded： Test according ISO 8655： Last modification： 10/17/12 15：53：47 Application Hints lf you have any questions concerning the application， you are welcome to contact us. Literature JULABO TECHNOLOGY(Beijing)Co.，LTD 地址：北京市朝阳区酒仙桥东路1号院M8号楼C厅3层301室 Add ： Room 301，C hall，M8 office building，No.1 jiuxianqiao east road ，Chaoyang District，Beijing，China Tel.：4008092068 昌Fax ： +86 (0)10 64390585 E-Mail ： info@julabo.cn Web： www.julabo.cn， www.julabo-visco.com 优莱博技术(北京)有限公司 Page of Date： Page of Date：