Determination of water content in food industy with Karl Fischer

Category: Food | Tags:
In food industry, moisture is being measured for various reasons. Some of those reasons include economic, food quality, labeling and microbial stability. Several methods can be used for moisture determination. One of the method is Karl Fischer Titration Method (KF).
The KF method is considered to be the most accurate method in everyday analysis. The advantages of this method are high accuracy and precision when the water content in the tested samples is in minimal quantities (includes free and bound water). Disadvantages of the method are that it is not applicable when the sample contains oxidizing or reducing substances (ie substances that react with one of the components of KF-reagents, peroxides, aldehydes, alkalis).
Karl Fischer reagents include iodine solution, sulfur dioxide, anhydrous methanol (and anhydrous pyridine).
There are two different techniques for water determination by Karl Fischer: Volumetric KF titration and coulometric KF titration.
Volumetric determination is being used for determination of water when the water content is down to 1% of water. The endopoint of reaction is determined potentiometrically.
Coulometric determination is the best for samples with less than 1% of water. The endpoint of reaction is being determined electrochemically.
In food industry, Karl Fischer method is used for water content determination in fruit juices, honey, flour, pasta, chips, cocoa powder, infants formulas, spices and condiments ect.
Karl Fischer can be used for petroleum industry, cosmetic industry, pharmaceutic industry, textile and wood industry.

Hanna Instruments can help you in measuring the water content in your products.

HI933-02

Volumetric Karl Fischer Titrator

For scientists and professionals who need exact water content determination from 0.01 to 100%, our new generation of the Volumetric Karl Fischer Titrator is engineered to meet or exceed your technical requirements while delivering a lower cost of ownership. With cutting-edge features packed into a compact design, this titrator delivers accurate results and requires less space in the lab. Get accurate water content determination at the push of a button. Designed for the modern lab, this karl fischer titrator is the perfect fit for your testing environment.
  • Compact design will save space in the lab without compromising your results.
  • Durable heat and chemical resistant body.
  • Sealed solvent system helps to keep water out of the system, while giving you minimal exposure to the reagents.
Dynamic Titrant Dosing
The dynamic dosing feature allows for timely and accurate titration results by relating the titrant volume dosed to the mV response from the titration reaction. This provides for larger doses near the beginning of a titration and smaller, more precise doses near the titration endpoint.
Drift Rate Compensation
The HI933 Volumetric Karl Fischer Titrator automatically adjusts the titration calculation to account for the effects of any ambient humidity entering the titration cell. This provides a more accurate result by correcting for water not present in the actual sample.
Titration Results Averaging
Successive results from a karl fischer titration method may be averaged with recording of the standard deviation.
Titrant Recordkeeping
The HI933’s titrant database can store information for up to 20 titrants. The database may be programmed to remind a user when to standardize their titrant, reducing error in analysis.
Selectable Endpoint Criteria
The HI933 employs a dual platinum pin electrode for bivoltammetric endpoint determination. Users may choose termination criteria based on mV stability times or drift rates.
Multistage Cell Preparation
A pre-titration stage eliminates residual water present in the solvent and the cell, providing a reliable baseline start to analysis. Standby mode then keeps the solvent dry between titrations and when the titrator is not in use.

HI934-02

Coulometric Karl Fischer Titrator

For scientists and professionals who need exact water content determination from 1 ppm to 5%, our new generation of the Coulometric Karl Fischer Titrator is engineered to meet or exceed your technical requirements while delivering a lower cost of ownership. With cutting-edge features packed into a compact design, this titrator delivers accurate results and requires less space in the lab. Get accurate water content determination at the push of a button. Designed for the modern lab, this karl fischer titrator is the perfect fit for your testing environment.

  • Compact design will save space in the lab without compromising your results.
  • Durable heat and chemical resistant body.
  • Sealed solvent system helps to keep water out of the system, while giving you minimal exposure to the reagents.
Dynamic Titrant Dosing
The dynamic titration speed allows for timely and accurate titration results by relating the amount of iodine generated to the mV response from the Karl Fischer reaction. This provides for a larger generation of iodine near the beginning of a titration and more precise pulses near the titration endpoint.
Drift Rate Compensation
The HI934 automatically adjusts the titration calculation to account for the effects of any ambient humidity entering the titration cell. This provides a more accurate result by correcting for water not present in the actual sample.
Selectable Endpoint Criteria
The HI934 employs a dual platinum pin electrode for bivoltammetric endpoint determination. Users may choose termination criteria based on mV stability times or drift rates.
Multistage Cell Preparation
A pre-titration stage eliminates residual water present in the solvent and the cell, providing a reliable baseline start to analysis. Standby mode then keeps the solvent dry between titrations and when the titrator is not in use.
Purposeful Generator Design
Two styles of generators are available for the HI934; a fritted design ideal for samples with low water content and high accuracy demand; and a fritless generator allowing for easier cleaning and maintenance.
Precision Iodine Generation
Our dosing algorithm allows for an extremely small amount of iodine necessary for the Karl Fischer reaction to be generated electrolytically using a pulsed current up to 400 mA, delivering iodine accurately and precisely.
Author:
Tajana Mokrović, mag.nutr.