This method describes how to determine the epichlorohydrin content of drinking water using solid-phase extraction.
Drinking water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
Epichlorohydrin is separated from a water sample by means of solid-phase extraction and is determined using gas chromatography with mass spectrometric detection (MS). Alternatively, an electron capture detector (ECD) can be employed.
This method describes how to determine iso-α-acids, α-acids and β-acids in isomerized pellets by means of reverse phase high pressure liquid chromatography (RP-HPLC).
Isomerized pellets intended for use in beer brewing or elsewhere in the food industry
The bitter substances in isomerized hop pellets contain a substantial amount of iso-α-acids; however, in addition to these, non-isomerized α-acids and β-acids are also present. In order to determine their content, a specific method is required.
After milling, the substances in question are extracted from the isomerized pellets using a diethyl ether/methanol mixture and a hydrochloric acid solution. The iso-α-acids, α-acids and β-acids dissolved in the ether phase are separated using reversed-phase high-performance liquid chromatography (RP-HPLC) and an elution gradient. They are then measured spectrophotometrically at wavelengths of 270 nm (iso-α-acids) and 314 nm (α-acids and β-acids).
Hop products with isomerized or reduced iso α-acids intended for use in beer brewing or elsewhere in the food industry
Hop products with isomerized or reduced iso α-acids are dissolved with methanol. The bitter acids are separated through reverse phase high-pressure liquid chromatography (RP-HPLC) and isocratic elution. They are then measured at a wavelength of 270 nm.
Standardized extraction process with potassium hydrogen phthalate at pH 4.0 for use with filter media/filter aids.
Suitable for all common filter media/filter aids.
Elements (cations) from filter media/filter aids are extracted for determination using AAS, ICP-OES or ICP-MS at a pH 4.0.
The sample is extracted with petroleum ether in a Soxhlet apparatus equipped with a reflux condenser; the solvent is evaporated and the crude fat residue weighed.
Hops and hop products intended for use in beer brewing or elsewhere in the food industry
The polyphenols are extracted from the hops using hot water. In an alkaline environment, they form a red pigment with iron (III) ions, which is measured spectrophotometrically at 600 nm.