Enrichment of the PAH is performed using solid phase extraction. The extract is obtained from the sample through separation with high performance liquid chromatography on the appropriate stationary phases under isocratic conditions. Detection is conducted with a fluorescence detector. The determination is quite sensitive because these polycyclic aromatic hydrocarbons possess substantial fluorescence properties. Since the fluorescence characteristics of these substances are substance-specific, they are determined using two spectra, the excitation and emission spectra. Thus, selective detection is possible. Through recognition of the specific spectra for each substance and the means of detection at the appropriate wavelengths, maximum sensitivity and selectivity are attainable.
The PAH compounds are concentrated through extraction with cyclohexane and evaporation. The separation is carried out by means of high-performance thin-layer chromatography. The results are evaluated through examination under UV light, followed by comparison of the Rf values with the reference substances.
This method describes how to determine the α-acids and β-acids in hop extract using high-pressure liquid chromatography.
Hop extract intended for use in beer brewing or elsewhere in the food industry
The method describes how to determine the content of benzo-(a)-pyrene in drinking water using high performance liquid chromatography.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
Refer to W-010.06.120 Quantitative Determination of Polycyclic Aromatic Hydrocarbons (PAH) in Drinking Water
The method describes how to determine pesticides and biocidal products in drinking water using high performance liquid chromatography.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
The determination is carried out by means of HPLC (refer to W-010.06.120 Quantitative Determination of Polycyclic Aromatic Hydrocarbons (PAH) in Drinking Water).
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).