Monier-Williams method

In one study, a modified Monier-Williams method has been utilized as a preparative procedure to obtain both the free and bound sulfite fractions. The two fractions were analyzed by HPLC with indirect photometric detection using a 250 X 4.6-mm LC-SAX column eluted with potassium hydrogen phtalate (0.15 g/L, pH 5.7) and detected at 280 nm. Levels of 5-10 ppm of S02 in foods, corresponding to 30 - 60 ng injected, were reliably detected by this method. The results confirmed that the chromatographic method, unlike the Monier-Williams method, is able to avoid the potential interference of volatile substances derived from matrices or utilized chemicals (36). The HPLC conditions are summarized in Table 3. 

The best reference that was found was AOAC method 990.31 [18] that was developed by Kim and Kim. The method was based on extensive work with a variety of foods and beverages. The incentive for the work was to find an alternative to the modified Monier-Williams method [23] which is time-consuming and labor-intensive. 

Much of the sulphur dioxide present in beer is in a bound form, for example, as the acetaldehyde bisulphite compound. The classical (Monier-Williams) method for the estimation of sulphur dioxide, adopted by the Institute of Brewing, involves the removal of SO2 from acidified beer in a stream of carbon dioxide and nitrogen at 100 C. The gas is absorbed in hydrogen peroxide and the sulphuric acid formed titrated. In Britain sulphur dioxide is a permitted preservative in beers ( > 70 ppm), ciders, and wines ( > 150 ppm) and the Monier-Williams method is official. The EBC-ASBC adopt a more sensitive colorimetric method in which the colour restored to acid-decolourized rosaniline hydrochloride is measured. 

Sulfurous acid total Foods Modified Monier-Williams method... 

A long-established procedure for the determination of sulfur dioxide is the Monier-Williams method in which sulfur dioxide is distilled from an acidified solution and the vapor passes through U-tubes containing hydrogen peroxide which oxidizes it to sulfuric acid. The acidity produced is then titrated with dilute standard alkali. This procedure is preferred to an iodimetric titration when volatile sulfur compounds are present as in mustard, onion, and horseradish. Sulfur dioxide may also be... 

Sulfur dioxide (SO2) is generally measured by indirect methods. The AOAC describes a modified Monier Williams method, while the Codex Alimentarius standards and EC directive recommend the modified Tanner method both are based on similar principles, involving the distillation of the SO2 from an acidified aqueous suspension of the food. The evolved gas is subsequently trapped in... 

Since its introduction in 1927, the Monier-Williams method has been modified from time to time, chiefly in connection with design of apparatus and conditions of refluxing and distillation (Nissen and Petersen, 1943 Thompson and Toy, 1945 and others). It has been applied to a wide variety of foods, dried and dehydrated fruits (Miller, 1927), dehydrated vegetables, juices, concentrates, wines, beers, etc. (Veisman and Svereva, 1937). 

Nissen, B. H., and Petersen, R. B. 1943. Determination of sulfur dioxide in beer. A modification of Monier Williams method. Ind. Eng. Chem., Anal. Ed. 16,129-130. 

AOAC. 2005b. Sulfurous acid (total) in food. Modified Monier-Williams method. In Official Methods of Analysis of AOAC International (18th ed.) eds. W. Horwtz and G. W. Latimer, Chapter 47. Gaithersburg, MD AOAC International, Official Method 962.16. 

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