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In an acidic sulfurous solution containing phosphorus, nitrate ions react with 2,6-dimethylphenol to produce 4-nitro-2,6-dimethylphenol.

The method is suitable for determining approx. 0.5–25 mg/l NO₃^-. If the ratio of chloride to nitrate ions is larger than 10, this may interfere with the reaction (if this is the case, according to DEV D 9-3, follow DIN 38405); likewise, nitrite ions exceeding approx. 0.2 mg/l may also interfere with the reaction. For their removal, refer to Remarks below.

In an acidic solution, nitrite reacts with primary aromatic amines, producing diazonium salts. Together with aromatic compounds, they form azo compounds, which contain an amino or hydroxyl group and exhibit an intense color.

A (modified) Congress wort is produced from malt samples prior to analysis. NDMA present in the Congress wort is extracted using dichloromethane followed by concentration of the eluate. The determination is performed with a gas chromatograph using a packed Carbowax 20M column with a specific TEA detector (thermal energy analyzer); nitrosodipropylamine (NDPA) serves as an internal standard.

This detector analyzes nitrosamine according to the following procedure:

After exiting the GC column, the separated substances are heated to 500 °C in a pyrolyzer. At this temperature, the N-NO bond of the nitrosamine is broken, thus forming an NO radical (NO۰): 

The gas mixture then flows through a special filter (CTR^TM gas stream filter), which only allows the carrier gas and the NO radicals to pass. After exiting the filter, the NO radicals flow into a reaction chamber along with ozone, which is created by a special generator. The following chemical reactions take place in the chamber: 

These NO radicals react with ozone, forming nitrogen dioxide in an excited state (NO₂•). The NO₂• molecules decompose spontaneously to form nitrogen dioxide in its common form (NO₂), emitting radiation (h•ν) with a wavelength of approx. 600 nm. 

Medium and high molecular weight proteins are precipitated by phosphomolybdic acid. The nitrogen is determined in the filtrate. Therefore, the results express the amount of low molecular weight proteins.

Separation of bromide, chloride, fluoride, nitrate, nitrite, oxalate, phosphate and sulfate through ion chromatography followed by conductivity detection

The hot break material (trub) and any hop particles which may be present in the wort, must first be removed. After the wort has been cooled to 2 °C, it is filtered through a glass fiber filter. The residue remaining on the filter is dried and then weighed.

Cold break material or cold trub refers to all material that settles out in the process of chilling wort after separation of the hot trub or hot break material. Cold trub can be filtered out of the wort and primarily consists of proteins (48–57 %), tannins (11–26 %) and carbohydrates (20–36 %). The amount of cold break material in wort depends on the quality and composition of the raw materials, brewhouse equipment and wort handling. In academic and professional circles, opinions regarding the significance of cold break material for downstream processes and for the quality of the finished beer are strongly divided [1, 2, 5]. Under certain circumstances, the quantity of cold break material in wort may exceed 250 mg/l, especially where accelerated fermentation is practiced. Ultimately, this can detract from the flavor of the finished beer [3]. Breweries, where removal of the cold break material has been practiced successfully, determine the quantity of cold break in their pitching wort at regular intervals, in order to evaluate the efficacy of their separation equipment.