Karl Fischer (KF) Moisture Testing Service
Moisture content is a critical factor affecting product quality, stability, and processability, particularly in industries such as pharmaceuticals, chemicals, food, and electronic materials. The Karl Fischer (KF) titration method, known for its high sensitivity, excellent selectivity, and broad applicability, has become an internationally recognized standard for moisture determination. As a professional third-party analytical testing laboratory, Alfa Chemistry offers KF moisture testing services based on both volumetric and coulometric methods, covering solid, liquid, and gaseous samples.
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What Sets Our Technique Apart
To ensure accuracy and reliability in moisture determination, the Karl Fischer (KF) titration method stands out as the preferred analytical technique across various industries due to its distinct advantages.
High Sensitivity
Capable of detecting moisture content down to microgram (μg) levels, making it ideal for trace moisture analysis.
Excellent Selectivity
Highly specific to water, minimizing interference from other volatile impurities.
Proven Methodology
Compliant with international standards such as ISO, ASTM, USP, and EP.
Dual-Platform Capability
Equipped with both volumetric and coulometric Karl Fischer systems to accommodate a wide range of sample types and moisture concentrations.
In Which Fields Can Karl Fischer Moisture Testing Be Applied?
Building on the proven accuracy and efficiency of KF titration, our advanced KF moisture analysis services are tailored to meet the diverse needs of multiple industries.
Pharmaceutical Industry
Chemical Industry
Food Industry
Materials Science
New Energy / Batteries
Research Institutions
What Are the Types and Working Principles of Karl Fischer Titration?
Volumetric Titration
In volumetric KF titration, a Karl Fischer reagent of known concentration—typically containing iodine, sulfur dioxide, pyridine (or other bases), and methanol—is gradually added to the sample until the reaction reaches completion, known as the titration endpoint. The core reaction is as follows:
I2 + SO2+ H2O + RNH3 → RNHSO4 + HI
In this reaction, iodine reacts with water in the presence of sulfur dioxide and a base to form hydriodic acid and an alkylammonium bisulfate salt. The moisture content is calculated based on the volume of KF reagent consumed. Therefore, the accuracy of this method largely depends on the precision of the burette and the controlled delivery of the reagent.
Coulometric Titration
Coulometric Karl Fischer titration is based on an electrochemical reaction in which iodine is generated in situ by electrolysis of an iodide-containing electrolyte. The iodine then reacts quantitatively with water present in the sample. The core reaction is the same as in the volumetric method:
2I-→I2+2e-
Unlike the volumetric method, coulometric titration does not require a reagent of known concentration. Instead, the moisture content is calculated by measuring the amount of electricity consumed during the electrolysis process. Since the amount of electric charge is directly proportional to the amount of iodine produced, this method offers higher precision and sensitivity, making it particularly well-suited for the determination of trace moisture levels.
What Is the Testing Capacity and What Are the Sample Requirements?
The sample must accurately represent the overall moisture distribution of the material to ensure uniformity in moisture content. The expected or estimated moisture level, along with the selected measurement technique, determines the amount of sample required for titration.
| Coulometric KF | Volumetric KF | ||
| [water] (ppm) | Min. Sample size (g) | [water] (ppm) | Min. Sample size (g) |
| 1 | 10 | 10 | 8 |
| 10 | 8 | 50 | 7 |
| 50 | 5 | 100 | 5 |
| 100 | 4 | 200 | 4 |
| 500 | 2 | 500 | 3 |
| 1000 | 1 | 1000 | 2 |
| 500 | 0.2 | ||
| 10000 | 0.1 | ||
| Suitable for trace moisture determination, commonly used for organic solvents, oils, and sensitive materials. | Suitable for samples with relatively high moisture content (such as active pharmaceutical ingredients and liquid chemicals). | ||
What Types of Samples Can Be Tested Using Karl Fischer Titration?
Organic/Inorganic Liquids
Such as solvents, oils, reaction mixtures, and additives
Solid Powders and Crystals
Including active pharmaceutical ingredients (APIs), intermediates, and polymers
Finished Products
Such as tablets, capsules, and other pharmaceutical formulations
Specialty Materials
Materials with extremely low moisture content or containing volatile components
Gases or Poorly Soluble Substances
Can be analyzed using headspace sampling or external introduction methods
Why Choose Us?
Extensive Experience
Years of expertise in moisture analysis, covering a wide range of complex sample types
Expert Team
Professional staff composed of senior analysts and quality auditors
Advanced Instrumentation
Equipped with original Karl Fischer titration systems imported from Switzerland and Germany
Fast Turnaround
Standard projects can be reported within 1–2 business days
Regulatory Compliance
Fully compliant with GLP, GMP, ISO 17025, and other relevant standards
One-Stop Service
Comprehensive support from sample pretreatment to final report interpretation
What Success Stories Can We Share?
Here are three case studies showcasing Karl Fischer (KF) Moisture Testing service conducted for other companies, highlighting the value and impact of our expertise.
Case 1: Moisture Testing of Active Pharmaceutical Ingredients (API) Supporting New Drug Registration
Client Background: A pharmaceutical company specializing in small molecule innovative drug development
Sample Type: Heat-sensitive API powder
Service Provided:
Coulometric Karl Fischer titration for quantitative moisture analysis of the API sample
Method validation conducted following ICH Q2(R1) guidelines, covering accuracy, repeatability, linearity, and specificity
Clear and compliant report structure aligned with drug registration technical documentation standards
Service Outcomes:
Test data successfully submitted as part of new drug quality research documentation
Client’s R&D team saved significant time on method development and validation, accelerating the registration process
Client Feedback:
"The testing workflow was efficient, the methodological validation rigorous, and the report ready for direct inclusion in registration dossiers, greatly improving our operational efficiency."
Case 2: Moisture Limit Monitoring for Solvent Purity Control in Chemical Manufacturing
Client Background: A fine chemicals company focused on product purity control
Sample Type: High-purity dichloromethane (DCM) and isopropanol (IPA)
Service Provided:
Regular moisture content determination of solvent batches using volumetric Karl Fischer titration
Strict control of sample exposure and use of anhydrous techniques to ensure accuracy
Establishment of moisture limit data to support product release specifications
Service Outcomes:
Effectively assisted the client in monitoring trace moisture introduced during production, improving product quality consistency
Test reports used for ISO quality system internal audits and client compliance submissions
Client Feedback:
"The service is stable and reliable, serving as a key partner in our solvent purity monitoring and batch release testing."
Case 3: Moisture Risk Control in Product Storage Stability for a Food Additives Manufacturer
Client Background: A natural food additives producer
Sample Type: Crystalline natural sweeteners (e.g., erythritol)
Service Provided:
Evaluation of moisture content changes under varying relative humidity conditions as requested by the client
Karl Fischer volumetric titration applied to monitor moisture trends over storage time
Provision of detailed trend charts and reports for internal stability risk assessments
Service Outcomes:
Assisted the client in developing appropriate packaging and storage recommendations to prevent hygroscopic clumping
Moisture control standards incorporated into product quality specifications for export compliance
Client Feedback:
"The detailed reports and reliable data from your lab have provided direct support for our scientific storage strategy development."
How Can You Partner with Us?
Pre-Engagement Communication
Clarify sample type, testing requirements, and applicable standards
Sample Receipt and Evaluation
Select the appropriate testing method based on sample condition
Testing Execution
Performed by experienced analysts to ensure precision and efficiency
Data Review and Reporting
Multiple quality control steps to issue a formal test report
Technical Support
Assistance with result interpretation and method recommendations to support subsequent development needs
Frequently Asked Questions (FAQ)
Q1. Will the presence of aldehydes, ketones, or amines in the sample affect Karl Fischer moisture testing results?
Yes. Certain chemical groups such as aldehydes, ketones, and strongly basic amines may react with KF reagents, causing elevated or skewed moisture results. Our experienced sample evaluation team can identify such interference risks in advance and select appropriate buffers or alternative solvents to ensure data accuracy and method suitability.
Q2. Can Karl Fischer testing measure bound water or crystal water?
Yes. Karl Fischer titration can measure not only free water but also many forms of bound water (such as crystal water). By selecting proper sample preparation techniques (e.g., heating, dissolution, or microwave assistance), we can release and accurately quantify bound water. This is widely applied in APIs, intermediates, and inorganic salts analysis.
Q3. Is it possible to test localized moisture distribution within a solid sample?
Karl Fischer titration provides an overall average moisture content and does not have spatial resolution capability. If localized moisture distribution analysis is required, we can recommend complementary techniques such as thermal analysis (e.g., TGA) or texture-related methods.
Q4. Is Karl Fischer testing applicable to emulsions, suspensions, or colloids?
Applicable, but requires careful handling. Such samples may pose challenges like emulsification, phase separation, or incomplete reaction. We may use co-solvents, heating, or ultrasonic treatment to improve reaction efficiency and completeness. Please consult with us beforehand for complex sample matrices to assess feasibility.
Q5. Can you handle toxic, corrosive, or hazardous samples?
We have the capability to handle samples with certain hazards or special requirements (e.g., halogenated hydrocarbons, organic peroxides, strongly acidic or alkaline materials), but prior communication and sample safety documentation are required. For highly hazardous chemicals, clients may need to provide MSDS and handling instructions.
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Reference
- Rivera‐Quintero, P., et al. "Experimental methods in chemical engineering: Karl Fischer titration." The Canadian Journal of Chemical Engineering 102.9 (2024): 2980-2997.
