KF Coulometrici
Determinare un basso contenuto di umidità e acqua nei campioni non è un problema con questi coulometri.
La titolazione Karl Fischer coulometrica è il metodo ideale per la determinazione di basse quantità d’acqua nei campioni (da 0.001% a 1% di acqua). La nostra gamma di coulometri soddisfa qualsiasi esigenza ed è combinabile con il metodo Karl Fischer con forno per l’analisi di campioni difficili.
- Determinazione accurata ed affidabile delle tracce di acqua nel campione, in un range da 0.001% a 1%
- Disponibilità di varie tipologie di coulometri, ad esempio stand-alone o con controllo da computer
- Possibilità di analizzare campioni difficili con il metodo con forno
- Conforme con FDA Regulation 21 CFR Part 11 and EudraLex, Volume 4, Annex 11
Una vasta gamma di Coulometrici
Metrohm offre una gamma di coulometri per soddisfare le tue necessità. Contattaci per sapere di più sui nostri coulometri.. Contattaci per saperne di più.
| Coulometro | Caratteristiche |
|---|---|
| OMNIS Coulometer |
Brochure: OMNIS Coulometer and OMNIS Sample Robot Oven (8.000.5475, PDF, 2.8MB) |
| Titrando coulometers |
Brochure: 851 Titrando / 852 Titrando (8.851.5002, PDF, 889 KB) |
| Ti-Touch coulometer |
Brochure: 916 Ti-Touch, 915 KF Ti-Touch, 917 Coulometer (8.916.5004, PDF, 900 KB) |
| Eco Coulometer |
|
Preparazione del campione e automazione per la titolazione KF coulometrica
In caso di campioni difficili, come ad esempio campioni solidi o che non dissolvono rapidamente, puoi utilizzare il nostro metodo di KF con forno. Con questa applicazione il campione è riscaldato in un forno fino al completo rilascio dell’acqua contenuta, il cui vapore è trasferito nella cella di titolazione per la misura.
La nostra offerta include sia il forni manuali, a postazione singola, sia autocampionatori con forni integrati per aumentare i campioni analizzabili.
Maggiori info sulla preparazione del campione per titolazione KF
Perchè utilizzare la titolazione KF coulometrica per la determinazione del contenuto di acqua?
Una serie di norme ufficiali riguardanti la titolazione coulometrica di karl fischer per la quantificazione dell’acqua:
| Standard | Name |
|---|---|
| ASTM D890 | Standard Test Method for Water in Liquid Pine Chemicals |
| ASTM D1123 | Standard Test Method for Water in Engine Coolant Concentrate by the KF Reagent Method |
| ASTM D1533 | Standard Test Method for Water in Insulating Liquids by Coulometric KF Titration |
| ASTM D3401 | Standard Test Methods for Water in Halogenated Organic Solvents and Their Mixtures |
| ASTM D4928 | Standard Test Method for Water in Crude Oils by Coulometric Karl Fischer Titration |
| ASTM D5460 | Standard Test Method for Rubber Compounding Materials - Water in Rubber Additives |
| ASTM D6304 | Standard Test Method for Determination of Water in Petroleum Products, Lubricating Oils, and Additives by Coulometric KF Titration |
| ASTM D7923 | Standard Test Method for Water in Ethanol and Hydrocarbon Blends by Karl Fischer Titration |
| ASTM E1064 | Standard Test Method for Water in Organic Liquids by Coulometric Karl Fischer Titratio |
| DIN EN ISO 12937 | Petroleum products - Determination of water - Coulometric KF titration method |
| ISO 10337 | Crude Petroleum - Determination of water - Coulometric KF titration method |
| UOP 481-10 | Water in Liquid Hydrocarbons, and Heavy Hydrocarbons by Vaporizer, using Coulometric Titration |
| USP | <921> Method 1c |
| EP | 2.5.32 Water: Micro Determination |
Coulometric Karl Fischer titrator – FAQs
What is coulometric Karl Fischer titration?
Coulometric titration is used to determine trace-levels of water in samples within a range of 10 µg to 200 mg water. However, larger amount of water (> 10 mg) require a lot of time and/or may exceed the water capacity of the KF reagent, which could lead to incorrect results.
The coulometric method uses electric current to generate the iodine that is needed for the Karl Fischer reaction. Metrohm KF Coulometers apply variable current strengths and pulse lengths, which allows precise "iodine addition" even in the region of the endpoint.
Learn more about coulometric KF titration in the application bulletin:
Coulometric water content determination according to Karl Fischer (AB-137, PDF, 228 KB)
Why is coulometric Karl Fischer titration used for water content determination?
Coulometric KF titration is a sensitive method suitable to determine low water contents between 0.001 and 1%. The coulometric method is an absolute method, meaning that there is no need for titer determination. In addition, a series of standards recommend coulometric Karl Fischer titration for water content determination:
| Standard | Name |
|---|---|
| ASTM D890 | Standard Test Method for Water in Liquid Pine Chemicals |
| ASTM D1123 | Standard Test Method for Water in Engine Coolant Concentrate by the KF Reagent Method |
| ASTM D1533 | Standard Test Method for Water in Insulating Liquids by Coulometric KF Titration |
| ASTM D3401 | Standard Test Methods for Water in Halogenated Organic Solvents and Their Mixtures |
| ASTM D4928 | Standard Test Method for Water in Crude Oils by Coulometric Karl Fischer Titration |
| ASTM D5460 | Standard Test Method for Rubber Compounding Materials - Water in Rubber Additives |
| ASTM D6304 | Standard Test Method for Determination of Water in Petroleum Products, Lubricating Oils, and Additives by Coulometric KF Titration |
| ASTM D7923 | Standard Test Method for Water in Ethanol and Hydrocarbon Blends by Karl Fischer Titration |
| ASTM E1064 | Standard Test Method for Water in Organic Liquids by Coulometric Karl Fischer Titratio |
| DIN EN ISO 12937 | Petroleum products - Determination of water - Coulometric KF titration method |
| ISO 10337 | Crude Petroleum - Determination of water - Coulometric KF titration method |
| UOP 481-10 | Water in Liquid Hydrocarbons, and Heavy Hydrocarbons by Vaporizer, using Coulometric Titration |
| USP | <921> Method 1c |
| EP | 2.5.32 Water: Micro Determination |
What is the difference between coulometric and volumetric titration?
The main difference between coulometric and volumetric Karl Fischer titration concerns titrant addition. In volumetric Karl Fischer titration, the titrant is added directly to the sample with a buret. Coulometric Karl Fischer titration features a generator electrode, which electrochemically generates the required iodine for the titration directly in the titration cell.
Metrohm offers titrator solutions that perform volumetric or coulometric titration on separate titrators as well as both volumetric and coulometric titration in a single instrument. Contact us to learn more.
What are the requirements for coulometric titration?
Requirements for coulometric titrations are the following:
- The process must take place with 100% current efficiency.
- No side reactions must occur.
- Oxidation or reduction must lead to a defined oxidation state.
Metrohm KF Coulometers meet these requirements with commercially available reagents.