植物油中皂化值检测方案

KMApplication Note NTIB-99307 Fat and Oil Saponification value of Fat and Oil Acidbase titration (non aqueous) by Automatic Potentiometric Titrator Standard JIS K0070ASTM D 5558ISO 3657 Standard Test Methodfor Fat and Oil 1.Abstract Saponification value is expressed by potassium hydroxide in mg required to saponifyone (1) gram of fat. It depends on the kind of fatty acid contained in the fat.Measurement of saponification value is performed according to the below listedofficial test methods. Here we test a sample of fatty acid. The sample is first saponified by adding0.5mol/L potassium hydroxide ethanol，and then the excessive potassium hydroxideis titrated with 0.5mol/L hydrochloric acid until the endpoint is reached.EP is determined by the maximum inflexion point on titration curve. 2.Reference 1) JIS K 0070 Test Method for Acidity， Saponification value， Ester value，Iodine value and Hydroxy value of Chemical products and Unsaponifiables 2)ASTM D 5558 Standard Test Method for Determination of the SaponificationValue of Fats and Oils 3)ISO 3657 Animal and vegetable fats and oils-Determination ofsaponification value 4))Method (I) 3.3.2 Saponification Value from Standard Test Method for Fatand Oil by Japanese Oil Chemistry Society 3.Cautions in measurement 1)When the sample is heated in flask for saponification， gently heat it so thatbackflow ethanol will not reach the top of cooling pipe fitted to the flask. 2)Replace junction liquid of reference electrode with saturated sodium perchlorateacetic acid. Http：//www. shxf17.com 4.Post-measurement care After the electrode is rinsed with water， keep the tip of electrode dipped in purewater for storage. 5.Test equipment Main unit：Automatic potentiometric titrator (Standard preamplifier STD-)Electrode： Standard Combination glass electrode (Change junction liquid to saturated sodium perchlorate aceticacid) 6.Reagent Reagent 0.5mol/L Hydrochloric acid (f=1.006) Reagent 0.5mol/L Potassium hydroxide·Ethanol 7.Measurement procedure 一Measurement- 1))Deliver 1.5 to 2.0g sample into a 200mL conical flask. 2))Add 25.0mL of 0.5mol/L potassium hydroxide Ethanol，and fix a cooling pipe tothe flask. 3)Gently heat the flask occasionally shaking while adjusting the heat so thatbackflow ethanol will not reach the top of cooling pipe. 4))After heated for 30 minutes， immediately cool it， and titrate with 0.5mol/L HClbefore the test liquid is solidified. 5))Perform blank test (without sample following step 1 to 4 above) for 3 times toobtain mean value of titration volume of 0.5mol/L hydrochloric acid. 8.Formula Saponification value(mg/g)=(BLl - EPl)xTF×Cl×K1/SIZE EPl Titration volume(mL) BLl Blank level (25.029mL) Reagent (HCl) factor(1.006) concentration conversion coefficient (28.05 mg/mL) (Potassium hydroxide in Eq.：56.11×0.5) K Unit conversion coefficient (1) SIZE ：Sample size(g) Http：//www.shxf17.com 9.Example of measurement -Ambient condition一 (The above printout data were obtained from titration by AT-510 unit) 《Titration parameter> Form： oftitration / APB No. the burette used in titration / Unit No.： APB Unit File numberDetector No.： the detector used in titration/ Unit of potential / Max Volume： of titration Wait Time： before titration starts/ Direction.： of titration 《Control parameter》 End Point No.： number of EPs / End sense： of EP detection / End Point Area： EP detection areaSeparation： ofpotential / Over Titr.Vol.over-titrated volume / Gain： sensitivity of detection signalData samp.Pot.： potential change of sampling signal/Data samp.Vol.： titration volume of sampling signalStability： of EP potential / Delay Time： before stability check /Limit Time： of stability checkIntegral Time： potential reading time for stability / Start Lim.Time： for stability check at start 1st Volume： first EP / 2nd Volume： second EP/ dE(1st-2nd)： Potential change 《Calculation parameter> Calc.Type： of formula / Conc.1 formula 1 / Unit： of results EP No. of calculation / Temp.Comp.： temperature compensation /C1(mg/mL)： concentration conversion coefficient K1： unit conversion coefficient / TF： factor of titration liquid /Blank1： blank level 1 ( 上海 旭 风 科学 仪器有限 公 司 上海 市闸北 区 万荣 路 388弄 17号90 4室 200 0 72 ) 周峰 13916388882 -Measurement results- Saponification value Sampleg Titration(mL) Saponification(mg/g) Mean SD RSD 327.6mg/g0.4620 mg/g 0.1410% 6.0526 6.0222 6.0570 327.6328.1 327.2 *The above test results were obtained by 3 tests of the same sample. *Red underline shows the data from page 3/4. 10. Summary Saponification value is expressed by potassium hydroxide in mg required to saponifyone (1) gram of fat. By measuring saponification value， mean molecular mass can beobtained. Saponification value is inversely related to mean molecular mass. The measurement results of fatty sample shows favorable repeatability with lesthan 0.3% relative standard deviation. Precise and reliable measurement is assured by the automated potentiometry.Saponification value can be perfectly measured by any of the following titrationsystems manufactured by Kyoto Electronics (KEM). 【AT-610】 【AT-510】 【AT-500N-1】 AwardedProducttofSupremeTechnology from Kyoto City ·Compact and cost performancemodel · Low cost and high performance·Easy view with back light LCD ·Easy key entry by touch panel oflarge color LCD (8-inch wide) ·PC card expands data memory forconvenience and versatility. ·GLP/GMP conformed model ·Simultaneous titration in parallel · Both potentiometric and KarlFischer moisture titration(coulometric"volumetric) can beperformed at a time. KeM KYOTO ELECTRONICS MANUFACTURINGCO.，LTD. Overseas Division： Yamawaki Bldg 9F，4-8-21 Kudan-minami，Chiyoda-ku， Tokyo 102-0074 JAPAN Phone：+81-3-3239-7333. Fax： +81-3-3237-0537 Head Office：56-2 Ninodan-cho，Shinden，Kisshoin，Minami-ku， Kyoto 601-8317 JAPAN Phone： +81-75-691-4122， Fax： +81-75-691-9961 URL： http：//www.kyoto-kem.com 上海旭风科学仪器有限公司 上海市闸北区万荣路388弄17号904室 20007 2 Http：//www. shxf17.com Tel： 021-66581985，63172460 Fax： 021-66581986 周峰13916388882 zhou-feng1027@163.com 上海旭风科学仪器有限公司 上海市闸北区荣路 el： Fax： 周峰 zhou-fengcom