Plastic, Rubber Quantification of Sodium Polyacrylate
Acidxbase titration by
Automatic Potentiometric Titrator
Standard
1.Abstract
Sodium polyacrylate is measured by adding pure water and adjusting pH to ｐH12～ 12.5 with 1mol/L sodium hydroxide, then titrating with 1mol/L Hydrochloric acid up to the endpoint, which is the maximum inflexion point on titration curve.. The concentration of Sodium polyacrylate is calculated from titration volume of Hydrochloric acid.
2.Reference
1) “Experiment and Calculation for Quantitative Analysis ” –Vol.2 by Seiji Takagi from Kyoritsu Publishing Company
3.Cautions in measurement
1) Handle with care when you work on chemicals.
上海今昊科学仪器有限公司 上海市博华路980弄25号602室388 201204 Tel：021-20230210 Fax：021-20230210 www.chemyiqi.com Email:[email protected]
TII-96004 Ver.01 1/4
4.Post-measurement care
Rinse the electrode with pure water, and keep it dipped in a beaker filled with pure water to refrain its tip from drying up.
5.Test equipment
Main unit：Automatic potentiometric titrator (Standard preamplifier STD-） Electrode：Option Glass electrode Option Ceramic type reference electrode Standard Temperature compensation electrode Option ： Power burette （for ｐH adjustment）
6.Reagent
Titrant ： 1mo1/L Hydrochloric acid ( f=1.004 ) Additive ： Pure water, 1mo1/L Sodium hydroxide
7.Measurement procedure
―Measurement― 1) Deliver precisely weighed 3g sample to a 200mL beaker. 2) Add 100mL pure water, and stir well. 3) Adjust pH to 12～12.5 with 1mol/L Sodium hydroxide. (Method 10: Auto control) Titrate with 1mol/L Hydrochloric acid to obtain concentration of Sodium polyacrylate. (Method 11: Auto control, Method 12: Auto cut-off)
8.Formula
Sodium polyacrylate ( mg/g ) = ( EP2 － EP1 ) × FA1 × C1 × K1 / SIZE EP1 ： EP1 titration volume ( mL ) EP2 ： EP2 titration volume ( mL ) FA1 ： Factor of titrant (1.004 ) C1 ： Concentration conversion coefficient ( 94mg/mL ) K1 ： Unit conversion coefficient ( 1 ) SIZE ： Sample size ( g )
上海今昊科学仪器有限公司 上海市博华路980弄25号602室388 201204 Tel：021-20230210 Fax：021-20230210 www.chemyiqi.com Email:[email protected]
TII-96004 Ver.01 2/4
9.Example of measurement －Ambient condition－ Room temperature：24 ℃ Humidity ： 47 ％ Weather ： Cloudy
- Titration parameter - ＊Titration parameter＊（Method 10） ＊Titration parameter＊（Method 12） Titration form ： EP Stop Titration form ： EP Stop Titration burette ： 03 Titration burette ： 01 Reagent name ： 1M-NaOH Reagent name ： 1M-HCl Detector number ： 1 Detector number ： 1 Preamplifier unit ： pH Preamplifier unit ： pH Max. volume of burette ： 20.0 mL Max. volume of burette ： 20.0 mL Auto stirrer ： Off Auto stirrer ： Off Wait time before titration： 0 sec Wait time before titration： 0 sec Titration direction ： Auto Titration direction ： Auto
＊Control parameter＊（Method 10） ＊Control parameter＊（Method 12） EP 1 potential ： 12.0 pH Number of EP(1-3) ： 1 EP 2 potential ： 12.0 pH Auto EP redetection ： Off Over-titration ： 0.0 mL End sense（Potential） ： 50.0 Gain ： 1 End sense (Differential）： 20.0 Control speed ： 0.5 Over-titration volume ： 0.0 mL Data sampling potential ： 4.0 mV Gain ： 1 Data sampling volume ： 0.5 mL Data sampling potential ： 4.0 mV Stability sense ： 0.5 mV/sec ＊Titration parameter＊（Method 11） Delay time before stability check： 15 sec Titration form ： EP Stop Limit time of stability check ： 30 sec Titration burette ： 01 Data sampling volume ： 0.2 mL Reagent name ： 1M-HCl Separate potential setup ： Off Detector number ： 1 Separate potential ： 0.0 pH Preamplifier unit ： pH EP potential setup ： Off Max. volume of burette ： 20.0 mL EP potential ： 0.0pH Auto stirrer ： Off Wait time before titration： 0 sec Titration direction ： Auto -Titration curve-
＊Control parameter＊（Method 11） Number of EP (1-3) ： 1 Auto redetection of EP ： Off End sense （potential） ： 50.0 End sense （differential）： 100.0 Over-titration volume ： 0.0 mL Gain ： 1 Control speed ： 0.5 Data sampling potential ： 4.0 mV Data sampling volume ： 0.5 mL Separate potential setup ： Off Separate potential ： 0.0 pH EP potential setup ： Off EP potential ： 0.0 pH
(The above printout data are obtained from titration by AT-410) ( Red underline shows the difference from the other method)
上海今昊科学仪器有限公司 上海市博华路980弄25号602室388 201204 ： ： www.chemyiqi.com Email:[email protected] Tel 021-20230210 Fax 021-20230210
TII-96004 Ver.01 3/4
－Measurement results－ Number of test ３ Mean 399.76 mgNaOH/g SD 0.72 mgNaOH/g RSD 0.18 % ＊The above results were obtained by 3 tests of the same sample.
10.Summary
Sodium polyacrylate is a polymer with high water absorbability with main structure of [-CH2-CH(CO2Na)-]n. High water absorbability comes from its gel formation absorbing water molecules into its netted structure. Such feature is made use of dispoable diaper and sanitary goods.
The test result shows a good repeatability with 0.18% relative standard deviation. Precise and reliable measurement is assured by the automated potentiometry. The analysis of Sodium polyacrylate can be perfectly made by any of the following titration systems manufactured by Kyoto Electronics (KEM).
【AT-610】 【AT-510】 【AT-500N-1】
Awarded Product of Supreme • Compact and cost performance • Low cost and high performance Technology from Kyoto City model • Easy view with back light LCD • Easy key entry by touch panel of • PC card expands data memory for • GLP/GMP conformed model large color LCD （8-inch wide） convenience and versatility. • Simultaneous titration in parallel • Both potentiometric and Karl Fischer moisture titration (coulometric・volumetric） can be performed at a time.
上海今昊科学仪器有限公司 上海市博华路980弄25号602室388 201204 Tel：021-20230210 Fax：021-20230210 www.chemyiqi.com Email:[email protected]
TII-96004 Ver.01 4/4