MACHEREY-NAGEL

The test for bitter units is based on the MEBAK method. The iso-alpha acids are extracted from the beer sample by shaking using a non-polar solvent. The enriched solvent is evaluated photometrically at 275 nm. The test impresses with its simple handling. The shaking out times have been optimized. The large 16 mm cuvette allows easy pipetting of the non-polar phase. The solvent is provided in the cuvette and can also be disposed of in this cuvette. The Photometer UV/VIS II includes free software functions for storing a batch-dependent blank value. The test has been pre-tested in a wide range of brewery laboratories and gives consistent results with the MEBAK method.

The test is based on the MEBAK method. The distillate of a beer sample is tested for the presence of vicinal diketones. These react to form a quinoxaline derivative. The evaluation is performed at 335 nm. The test is easy to perform and produces reliable results. The large 16 mm cuvette allows a lower measuring limit than conventional rapid tests and thus covers the measuring range that is important for breweries particularly well. The dry reagent is dosed via a freeze-dried Nanofix capsule, which ensures a long shelf life. Together with the pre-dosed reagent, the test offers maximum user safety. The reagents are disposed of in the used cuvette, which is easily taken back.

The chemical oxygen demand (COD) is one of the most important parameters for the assessment of industrial and municipal wastewater. As a cumulative parameter, COD determines all chemically oxidizable components present in water. Hence, this includes not only biodegradable substances (as in the BOD5), but also chemical compounds that cannot be determined by biological oxidation (e.g. nitrogen compounds such as nitrites). It has also the advantage of a faster availability compared to BOD. The COD indicates the contamination of a water sample. It is therefore also used as an evaluation parameter to determine pollution units in discharges under the German Wastewater Charges Act. By definition (ISO 15705), the COD is the concentration of oxygen that is equivalent to the mass of potassium dichromate that is consumed in total oxidation of organic substances present in the water sample. Mercury sulfate and silver sulfate as well as sulfuric acid are listed as auxiliary reagents.

Chlorine dioxide is considered one of the most commonly used disinfectants in drinking and industrial water. The reactivity and rapid decay of the molecule makes measurement at the sampling point necessary. With a portable photometer PF12+ the chlorine dioxide value can be determined at the dosing unit. The round cell test is particularly easy to handle and minimizes user error to a minimum. The measuring range is optimal for setting systems at the drinking water limit.

The spectrophotometer NANOCOLOR UV/VIS II is a high-precision instrument applicable in all areas of water and wastewater analysis. MACHEREY‑NAGEL revolutionizes the daily laboratory work with this new spectrophotometer by the combination of premium high-tech components with outstanding usability.