Karl Fischer & Potentiometric Titration Application Library
Drugs and Medicines – KF Volumetry, Back-Titration, Japanese Pharmacopoeia – Suitability test | Karl Fischer titrator AQV-300/MOIVO-A19
Water contents of drugs and medicines could be determined by Karl Fischer volumetric titrator. In volumetric titration, the titrant have a factor which means the ability to react with how many milligrams of water per 1 mL of titrant. Factor is pre-determined before sample measurement and water content of sample is calculated from consumed titrant volume within sample measurement.
There are two methods in KF volumetric titration, forward-titration and back-titration. Forward-titration is used in general. However, some of the sample should be measured by back-titration method according to Pharmacopeias.
In this report, the suitability test of Japanese Pharmacopoeia Eighteenth Edition was performed for dextromethorphan hydrobromide monohydrate, also introduced in Application Data No. 11, with back-titration method. Please refer to Application Data No. 11 for the factor determination of titrants procedure and the repeatability of measurement results for dextromethorphan hydrobromide monohydrate.
There are two methods in KF volumetric titration, forward-titration and back-titration. Forward-titration is used in general. However, some of the sample should be measured by back-titration method according to Pharmacopeias.
In this report, the suitability test of Japanese Pharmacopoeia Eighteenth Edition was performed for dextromethorphan hydrobromide monohydrate, also introduced in Application Data No. 11, with back-titration method. Please refer to Application Data No. 11 for the factor determination of titrants procedure and the repeatability of measurement results for dextromethorphan hydrobromide monohydrate.
Drugs and Medicines – KF Volumetry, Japanese Pharmacopoeia – Suitability test | Karl Fischer titrator AQV-300/MOIVO-A19
Water contents of drugs and medicines could be determined by Karl Fischer volumetric titrator. In volumetric titration, the titrant have a factor which means the ability to react with how many milligrams of water per 1 mL of titrant. Factor is pre-determined before sample measurement and water content of sample is calculated from consumed titrant volume within sample measurement.
In the method of “Water determination (Karl Fischer method)” in Japanese Pharmacopoeia Eighteenth Edition, the suitability test is described as a verification procedure when modifying the test procedures. In this report, a case example of suitability test is introduced with using glycerin as a simulated measurement sample.
In the method of “Water determination (Karl Fischer method)” in Japanese Pharmacopoeia Eighteenth Edition, the suitability test is described as a verification procedure when modifying the test procedures. In this report, a case example of suitability test is introduced with using glycerin as a simulated measurement sample.
Sugars – KF Volumetry, granulated sugar Factor standardization with water standard | Karl Fischer titrator AQV-300/MOIVO-A19
Water contents of granulated sugar could be determined by Karl Fischer volumetric titrator. In volumetric titration, titrant have a factor which means the amount to react with water per 1 mL of titrant. The factor is pre-determined before sample measurement and water content of sample is calculated from the consumed titrant volume by sample measurement.
This application introduces an example for the water determination in granulated sugar. Due to the low water content of this sample, a relatively large amount of sample must be added, but the solubility in methanol as titration solvent is not sufficient. Sugars have tendency to dissolve in formamide. Therefore a mixed solvent of formamide and methanol was chosen as the titration solvent. To make it easier to dissolve the sample, the titration cell was heated to 45 °C using an outer chamber for flowing warm water.
Since the water content of the granulated sugar is often a few hundred ppm, the titrant with low factor value, as 1 mg/mL was used. When pure water is used as the standard material of factor standardization for low factor titrant, the amount of pure water added should be as small as 10 to 20 mg, which makes accurate addition and weighing difficult. Therefore, water standard material which is the solution containing 1 % of water sealed in glass ampoule is used for the factor standardization.
This application introduces an example for the water determination in granulated sugar. Due to the low water content of this sample, a relatively large amount of sample must be added, but the solubility in methanol as titration solvent is not sufficient. Sugars have tendency to dissolve in formamide. Therefore a mixed solvent of formamide and methanol was chosen as the titration solvent. To make it easier to dissolve the sample, the titration cell was heated to 45 °C using an outer chamber for flowing warm water.
Since the water content of the granulated sugar is often a few hundred ppm, the titrant with low factor value, as 1 mg/mL was used. When pure water is used as the standard material of factor standardization for low factor titrant, the amount of pure water added should be as small as 10 to 20 mg, which makes accurate addition and weighing difficult. Therefore, water standard material which is the solution containing 1 % of water sealed in glass ampoule is used for the factor standardization.
Sugars – KF Volumetry, Powder Sample Glucose, fructose, and sucrose | Karl Fischer titrator AQV-300/MOIVO-A19
Water contents of sugars could be determined by Karl Fischer volumetric titrator. In volumetric titration, titrant have a factor which means the capacity to react with water per 1 mL of titrant. Factor is pre-determined before sample measurement and water content of sample is calculated from consumed titrant volume by sample measurement.
This application introduces an example for the water determination in glucose, fructose, and sucrose. Sugars have tendency to dissolve in formamide. Therefore a mixed solvent of formamide and methanol was chosen as the titration solvent.
This application introduces an example for the water determination in glucose, fructose, and sucrose. Sugars have tendency to dissolve in formamide. Therefore a mixed solvent of formamide and methanol was chosen as the titration solvent.
Ketones and Aldehydes – KF Volumetry, Direct-Injection Methyl ethyl ketone, Acetone, and Cyclohexanone | Karl Fischer titrator AQV-300/MOIVO-A19
Water contents of ketones and aldehydes could be determined by Karl Fischer volumetric titrator. In volumetric titration, titrant have a factor which is the capacity to react with water per 1 mL of titrant. Factor is pre-determined before sample measurement and water content of sample is calculated from consumed titrant volume by sample measurement.
When the sample is liquid, generally sample is measured by direct injection into the titration cell. Dehydrated methanol is generally used for titration solvent. However, in the measurement of ketones and aldehydes, since these react with methanol to produce water, the measurement result tends to be higher than the true value (formula (1)).
R₂CO + 2CH₃OH → R₂C(OCH₃)₂ + H₂O ・・・(1)
For above reason, Karl Fischer reagent without methanol should be used for water determination of ketones and aldehydes. There are commercially available reagents with a special composition for ketones and aldehydes. This chapter introduces an example for the water determination in methyl ethyl ketone, acetone and cyclohexanone with water added to them to 1 %. These samples are often used as paint solvents, raw materials of adhesives, and synthetic resins.
When the sample is liquid, generally sample is measured by direct injection into the titration cell. Dehydrated methanol is generally used for titration solvent. However, in the measurement of ketones and aldehydes, since these react with methanol to produce water, the measurement result tends to be higher than the true value (formula (1)).
R₂CO + 2CH₃OH → R₂C(OCH₃)₂ + H₂O ・・・(1)
For above reason, Karl Fischer reagent without methanol should be used for water determination of ketones and aldehydes. There are commercially available reagents with a special composition for ketones and aldehydes. This chapter introduces an example for the water determination in methyl ethyl ketone, acetone and cyclohexanone with water added to them to 1 %. These samples are often used as paint solvents, raw materials of adhesives, and synthetic resins.
Drugs and Medicines – KF Volumetry, Powder Sample Lactose hydrate and L-Histidine hydrochloride hydrate | Karl Fischer titrator AQV-300/MOIVO-A19
Water contents of drugs and medicines are usually determined by Karl Fischer volumetric titrator. In volumetric titration, titrant have a factor which means the capacity to react with water per 1 mL of titrant. Factor is pre-determined before sample measurement and water content of sample is calculated from consumed titrant volume within sample measurement.
This application introduces an example for the water determination in lactose hydrate and L-histidine hydrochloride hydrate with reference to Japanese Pharmacopeia. Sample is measured by direct injection into the cell. When the solubility of the sample in methanol is not sufficient, use a mixed solvent of methanol and formamide as the titration solvent.
Reference
1) Japanese Pharmacopoeia Seventeenth Edition
This application introduces an example for the water determination in lactose hydrate and L-histidine hydrochloride hydrate with reference to Japanese Pharmacopeia. Sample is measured by direct injection into the cell. When the solubility of the sample in methanol is not sufficient, use a mixed solvent of methanol and formamide as the titration solvent.
Reference
1) Japanese Pharmacopoeia Seventeenth Edition
Drugs and Medicines – KF Volumetry, Powder Sample Sodium Lauryl Sulfate and Benzalkonium Chloride | Karl Fischer titrator AQV-300/MOIVO-A19
Water contents of drugs and medicines could be determined by Karl Fischer volumetric titrator. In volumetric titration, titrant have a titer which means the capacity to react with water per 1 mL of titrant. Factor is pre-determined before sample measurement and water content of sample is calculated from consumed titrant volume within sample measurement.
When the sample is solid, firstly sample is measured by direct injection into the cell. Dehydrated methanol is used for titration solvent. The titration solvent may change to a composition suitable for dissolving the sample. If the sample is insoluble to titration solvent, heat-evaporation method is appropriate to these samples. An example for water contents measurements of sodium lauryl sulfate and benzalkonium chloride performed by direct injection method are introduced here. The measurement method was determined with reference to Japanese Pharmacopeia.
Reference
1) Japanese Pharmacopoeia Seventeenth Edition
When the sample is solid, firstly sample is measured by direct injection into the cell. Dehydrated methanol is used for titration solvent. The titration solvent may change to a composition suitable for dissolving the sample. If the sample is insoluble to titration solvent, heat-evaporation method is appropriate to these samples. An example for water contents measurements of sodium lauryl sulfate and benzalkonium chloride performed by direct injection method are introduced here. The measurement method was determined with reference to Japanese Pharmacopeia.
Reference
1) Japanese Pharmacopoeia Seventeenth Edition
Drugs and Medicines – KF Volumetry, Back-Titration, Dextromethorphan Hydrobromide Monohydrate | Karl Fischer titrator AQV-300/MOIVO-A19
Water contents of drugs and medicines could be determined by Karl Fischer volumetric titrator. In volumetric titration, the titrant have a factor which means the ability to react with how many milligrams of water per 1 mL of titrant. Factor is pre-determined before sample measurement and water content of sample is calculated from consumed titrant volume within sample measurement.
There are two methods in KF volumetric titration, forward-titration and back-titration. Forward-titration is used in general. However, some of the sample should be measured by back-titration method according to Pharmacopeias. In back-titration method, firstly excess amount of KF titrant is added to the water contained in the sample, and then the remaining unreacted of KF titrant is titrated with water-in-methanol solution. Therefore, it is necessary to measure the factor not only KF titrant but also the water-in-methanol before the sample measurement.
An example for water contents measurements of dextromethorphan hydrobromide monohydrate performed by back-titration method is introduced here. The measurement method was determined with the reference to Japanese Pharmacopeia. Please refer to Application Data No. 22 for the suitability test of Japanese Pharmacopoeia eighteenth edition by the back titration method.
Reference
1) Japanese Pharmacopoeia Eighteenth Edition
There are two methods in KF volumetric titration, forward-titration and back-titration. Forward-titration is used in general. However, some of the sample should be measured by back-titration method according to Pharmacopeias. In back-titration method, firstly excess amount of KF titrant is added to the water contained in the sample, and then the remaining unreacted of KF titrant is titrated with water-in-methanol solution. Therefore, it is necessary to measure the factor not only KF titrant but also the water-in-methanol before the sample measurement.
An example for water contents measurements of dextromethorphan hydrobromide monohydrate performed by back-titration method is introduced here. The measurement method was determined with the reference to Japanese Pharmacopeia. Please refer to Application Data No. 22 for the suitability test of Japanese Pharmacopoeia eighteenth edition by the back titration method.
Reference
1) Japanese Pharmacopoeia Eighteenth Edition
Drugs and Medicines – KF Volumetry, Direct-Injection Propylene glycol and Glycerin | Karl Fischer titrator AQV-300/MOIVO-A19
Water contents of drugs and medicines could be determined by Karl Fischer volumetric titrator. In volumetric titration, titrant have a titer which means the capacity to react with water per 1 mL of titrant. Factor is pre-determined before sample measurement and water content of sample is calculated from consumed titrant volume within sample measurement.
When the sample is liquid, generally sample is measured by direct injection into the cell. Dehydrated methanol is used for titration solvent. The titration solvent may change to a composition suitable for dissolving the sample.
Examples for water contents measurements of propylene glycol and glycerin performed by direct injection method are introduced here. The measurement method was determined with reference to Japanese Pharmacopeia.
Reference
1) Japanese Pharmacopoeia Seventeenth Edition
ASTM E203 : Standard Test Method for Water Using Volumetric Karl Fischer Titration
ASTM D4377 : Standard Test Method for Water in Crude Oils by Potentiometric Karl Fischer Titration
ASTM D890 : Standard Test Method for Water in Liquid Pine Chemicals
When the sample is liquid, generally sample is measured by direct injection into the cell. Dehydrated methanol is used for titration solvent. The titration solvent may change to a composition suitable for dissolving the sample.
Examples for water contents measurements of propylene glycol and glycerin performed by direct injection method are introduced here. The measurement method was determined with reference to Japanese Pharmacopeia.
Reference
1) Japanese Pharmacopoeia Seventeenth Edition
ASTM E203 : Standard Test Method for Water Using Volumetric Karl Fischer Titration
ASTM D4377 : Standard Test Method for Water in Crude Oils by Potentiometric Karl Fischer Titration
ASTM D890 : Standard Test Method for Water in Liquid Pine Chemicals