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main / offer for laboratory / reagents for instrumental analysis / reagents for water determination using Karol Fischer method

    Please, take a look at our offer as well as at information concerning water determination method using the Karol Fischer reagent, free of pyridine:  

TITRAQUAL
PYRIDINE FREE REAGENT OF K. FISCHER


    The base of the water determination method is the reaction within which iodine reacts with sulfur dioxide at presence of water according to the equation below:

J2 + SO2 + 2H2O -> 2HJ + H2SO4

    This reaction was discovered in 1935 by Karol Fischer who utilized it for elaboration of the method small quantities of water detection. The classical K. Fischer's reagent consists of two components:     

  • component A is the pyridine complex with SO2 dissolved in surplus of the inert solvent which is methanol,     
  • component B is the standard solution of iodine in methanol.
        In Titraqual the pyridine in component A was replaced by the basic amine - diethanolamine which is well soluble in water and methanol.

        Titraqual consists of two components:     
  • Titraqual - Solvent acting the role of reagent and solvent for a sample,     
  • Titraqual - Titrant, which is the titrating solution.
        Titraqual due to appropriate quantitive and qualitative selection of components is characteristic with:
  • significantly reduced toxicity,
  • longer durability,
  • short time of analysis performance,
  • work comfort due to pyridine elimination.
        Titraqual is used for free and crystalization water determination in organic and inorganic products, as well solid as liquid. The reagent titer is 3 - 7 mg H2O/ml.

        TITRAQUAL's TITER DETERMINATION
        The titer determination and titration itself can be performed visually or using the potentiometry method.
        Put 20 ml of Titraqual - Solvent into a vessel used for titration and titrate using Titraqual - Titrant up to the end point. Add 1 - 2 drops of water (0.01 - 0.05 g) weighed with accuracy of 0.0002 g to the titrated Titraqual - Solvent and titrate up to the end point.
        The Titraqual's titer (water quantity in miligrams equivalent to 1 ml of Titraqual reagent) in mg H2O/ml should be calculated using the formula below:

    w którym:
    m - weight of added water
    V - volume of Titraqual - Titrant used for added water titration in ml.

        EXECUTION OF WATER CONTENT DETERMINATION
        Put 20 ml of Titraqual - Solvent into a vessel used for titration and titrate it using Titraqual - Titrant up to the end point. Then add sample weighed with the accuracy of 0.0002 g or measured using the pipette and titrate up to the end point. A sample quantity depends on forecasted water content (e.g. approx. 5 g at water content of 0.1%).
    20 ml of Titraqual - Solvent is enough for determination of approx. 100 ml of H2O in a sample being examinated.

        Water content in percentage by weight in the sample examined should be calculated using the formula below:


    w którym:
    T - Titraqual's titer, mg H2O/ml
    V - Titraqual's - Titrant volume used for the examined sample titration, ml
    m - examined sample weight, g

        Note:
        In the case of necessity to perform determination in other solvent than methanol due to requirement of standard concerning examined preparation, one should add a portion of this solvent to the portion of 20 ml of Titraqual --Solvent, execute the preliminary titration, add a sample and execute the main titration up to the end point.
        Titraqual can be used in the similar way as the K. Fischer's reagent which is available on the market. To do so mix Titraqual - Solvent with Titraqual - Titrant in 1:1 ratio and titrate water using this mixture and using dewatered methanol for preliminary titration. Such prepared reagent should be used on a day of its preparation only - its titer is 2 - 3 mg H2O/ml.
        To acquaint in detail with the methodology of water determination using K. Fischer reagent the Polish standard PN-81/C-04959 "Water content determination using Karol Fischer method in organic and inorganic products" is recommended.

        References:
    1. FISCHER K. Neues Verfahren zur massanalytischen Bestimmung des Wassergehaltes von Flüssigkeiten und festen Körpern, Angew, Chemie 48, 394-396 (1935)
    2. SHERMAN F.B. Determination of water with a modified Karl Fischer reagent, Talanta 27, 1067-1072 (1980)
    3. SCHOLZ E. FRESENIUS Z. Anal. Chem. 303, 203 (1980)
    4. WIELAND G. Wasserbestimmung durch Karl Fischer Tritration. GIT VERLAG GmbH DARMSTADT (1985)
    5. SCHOLZ E. Karl Fischer Tritration - Methoden zur Wasser Bestimmung, SPRINGER VERLAG BERLIN, HEIDELBERG, NEW YORK, TOKYO (1984)


        Sales: Local Distributors or Sales Department of POCH S.A., tel. +48 32 23-92-378.
        Technical support: Export Department, mail: export@poch.com.pl









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