Karl Fischer & Potentiometric Titration Application Library
Quantitative determination of sodium citrate | Autotitrator
Sodium citrate is used as anticaking agent for blood in pharmaceutical field. Quantitative determination method for sodium citrate is stipulated in Japanese Pharmacopoeia.
This report introduces an example of potentiometric titration for sodium citrate that well-dried sample is dissolved in acetic acid, then it is titrated with perchloric acid – acetic acid standard solution.
C₆H₅Na₃O₇ ＋ 3HClO₄ → C₆H₈O₇ ＋ 3NaClO₄
This report introduces an example of potentiometric titration for sodium citrate that well-dried sample is dissolved in acetic acid, then it is titrated with perchloric acid – acetic acid standard solution.
C₆H₅Na₃O₇ ＋ 3HClO₄ → C₆H₈O₇ ＋ 3NaClO₄
Standardization of perchloric acid in acetic acid with potassium hydrogen phthalate | Autotitrator
Measurement method with perchloric acid – acetic acid standard solution is defined as a quantitative determination method for each drug and medicine in Japanese Pharmacopoeia. Standardization of perchloric acid – acetic acid standard solution with potassium hydrogen phthalate is also described there. This report introduces the standardization procedure that potassium hydrogen phthalate is dissolved in acetic acid, then it is titrated with perchloric acid – acetic acid standard solution. The factor of perchloric acid – acetic acid standard solution is determined with potentiometric titration. 1 mol potassium hydrogen phthalate reacts with 1 mol perchloric acid quantitatively on this titration (formula 1).
Purity determination for papaverine hydrochloride by perchloric aid titration | Autotitrator
Determination for papaverine hydrochloride is defined in Japanese Pharmacopoeia. Papaverine hydrochloride is used for improvement of vasodilatation and symptoms on gastritis, disease of biliary tract (gallbladder) system, acute arterial embolus, acute pulmonary embolism, peripheral circulatory failure, and inadequate coronary circulation.
The purity determination of papaverine hydrochloride using potentiometric titration with perchloric acid titrant is introduced in this report. Sample is dissolved by heating with acetic anhydride / glacial acetic acid mixture and cooled to room temperature. After that, the titration is performed, 1 mol papaverine hydrochloride reacts with 1 mol perchloric acid quantitatively.
The purity determination of papaverine hydrochloride using potentiometric titration with perchloric acid titrant is introduced in this report. Sample is dissolved by heating with acetic anhydride / glacial acetic acid mixture and cooled to room temperature. After that, the titration is performed, 1 mol papaverine hydrochloride reacts with 1 mol perchloric acid quantitatively.
Sodium chloride in peritoneal dialysis solution | Autotitrator
This report introduces an example of measurement for sodium chloride in peritoneal dialysis solution with precipitation titration. The sample is acidified by nitric acid and the concentration of sodium chloride is determined by precipitation titration with silver nitrate titrant using the silver / reference electrode.
NaCl ＋ AgNO₃ → AgCl ＋ NaNO₃
NaCl ＋ AgNO₃ → AgCl ＋ NaNO₃
Available iodine in mouthwash (Povidone-iodine) | Autotitrator
Determination method of available iodine in mouthwash containing povidone-iodine which is described in Japanese Pharmacopoeia is introduced here.
Dispense the sample and dilute it with DI water. Redox titration with sodium thiosulfate is performed based on the following formula (1).
I₂ ＋ 2Na₂S₂O₃ → 2NaI ＋ Na₂S₄O₆・・・(1)
Dispense the sample and dilute it with DI water. Redox titration with sodium thiosulfate is performed based on the following formula (1).
I₂ ＋ 2Na₂S₂O₃ → 2NaI ＋ Na₂S₄O₆・・・(1)
Determination of sodium acetate with perchloric acid titration | Autotitrator
Sodium acetate is widely used in chemical and medical industry (E.g. Buffer, Antifreezing agent, Alkalizing supplements, Dye chemical, Hydragogue). Determination method of sodium acetate is described on Japanese Pharmacopoeia and Japanese Industrial Standard (JIS K8371). Both methods employ perchloric acid titration method, dissolve the sample in glacial acetic acid and titrate with perchloric acid – acetic acid standard solution. Endpoint is detected by potentiometric titration with glass / reference electrodes.
CH₃COONa ＋ HClO₄ → CH₃COOH ＋ NaClO₄
CH₃COONa ＋ HClO₄ → CH₃COOH ＋ NaClO₄
Iodine value measurement for cooking oil | Autotitrator
Fatty acid in cooking oil, for example, oleic acid and linoleic acid absorb one or two of iodine molecules. Other kinds of cooking oils also absorb specific amount of iodine.
Iodine value means the “g” value of halogen which adhere to 100 g of sample; it is defined as indicators for unsaturated bond components of oils and fat in Pharmacopoeias: JP, USP, and EP.
There are two kinds of measuring methods such as Hanus method and Wijs method for Iodine value measurement. The former uses iodine bromide and the latter uses iodine chloride as halogen. In this chapter, the measurement example using more popular Wijs method is introduced.
Iodine value means the “g” value of halogen which adhere to 100 g of sample; it is defined as indicators for unsaturated bond components of oils and fat in Pharmacopoeias: JP, USP, and EP.
There are two kinds of measuring methods such as Hanus method and Wijs method for Iodine value measurement. The former uses iodine bromide and the latter uses iodine chloride as halogen. In this chapter, the measurement example using more popular Wijs method is introduced.
Acid value of cooking oil | Autotitrator
Acid value of oils and fats is defined as “amount (mg) of potassium hydroxide required to neutralize fatty acid in 1 g of sample” (Formula (1)).
R-COOH + KOH → R-COOK + H₂O ・・・(1)
It is used for evaluation of free fatty acid content as quality index of oils and fats. This method is described in a variety of official standards such as “Japan Agricultural Standards” and Pharmacopoeias. Example of titration for acid value in cooking oil is introduced here.
Reference
1) Japanese Pharmacopoeia Seventeenth Edition
R-COOH + KOH → R-COOK + H₂O ・・・(1)
It is used for evaluation of free fatty acid content as quality index of oils and fats. This method is described in a variety of official standards such as “Japan Agricultural Standards” and Pharmacopoeias. Example of titration for acid value in cooking oil is introduced here.
Reference
1) Japanese Pharmacopoeia Seventeenth Edition
Continuous measurement of citric acid and vitamin C in soft drink | Autotitrator
Example of sequential titration for vitamin C and citric acid in a soft drink is introduced here.
(1) Firstly, perform neutralization titration for citric acid with sodium hydroxide standard solution.
(2) After the titration, add acetic acid to adjust to acidic pH. Perform redox titration for vitamin C (ascorbic acid) by iodine standard solution.
The sequential titration of citric acid and vitamin C will be possible by additional option (buret and simplified dispenser).
(1) Firstly, perform neutralization titration for citric acid with sodium hydroxide standard solution.
(2) After the titration, add acetic acid to adjust to acidic pH. Perform redox titration for vitamin C (ascorbic acid) by iodine standard solution.
The sequential titration of citric acid and vitamin C will be possible by additional option (buret and simplified dispenser).
Salt Content in Soy Sauce | Autotitrator
The determination method of salt content in soy sauce is described as “Measurement of Salt Content” in JAS (Japanese Agriculture Standard). Potentiometric titration and Mohr method is defined in JAS as determination method of salt content, potentiometric titration is more common method because of its ease and high precision. The sample is acidified by nitric acid and the concentration of salt is determined byprecipitation titration with silver nitrate titrant using the silver electrode.
NaCl ＋ AgNO₃ → AgCl ＋ NaNO₃
Successive measurement of acid and salt in dressing | Autotitrator
An example of successive determination of concentration of acid and salt chloride in dressing is introduced here. Acid and salt are determined as acid and sodium chloride.
At first, titration of acetic acid with sodium hydroxide titrant is performed. Next, the sample solution is acidified by adding nitric acid, then titration of sodium chloride is performed with silver nitrate titrant.
* The titration for sodium chloride with silver nitrate has to be performed under acidic condition using nitric acid.
At first, titration of acetic acid with sodium hydroxide titrant is performed. Next, the sample solution is acidified by adding nitric acid, then titration of sodium chloride is performed with silver nitrate titrant.
* The titration for sodium chloride with silver nitrate has to be performed under acidic condition using nitric acid.
