The method describes how to determine acrylamide in drinking water using gas chromatography.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
The method facilitates the determination of trace amounts of acrylamide monomers in aqueous matrices and is based upon the bromination of the acrylamide double bond. The reaction product (2,3-dibromopropionamide) is extracted from the mixture with ethyl acetate after precipitation with sodium sulfate. The extract is purified in a Florisil column and analyzed using gas chromatography (GC/ECD). The detection limit in aqueous matrices is approx. 0.032 µg/l.
This method describes how to measure the benzene content of drinking water using an extraction technique.
Drinking water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
The unfiltered water sample is extracted using a non-polar solvent (e.g., pentane), and the extract is measured using gas chromatography with a flame ionization detector.
Drinking water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
Due to physico-chemical properties of these substances, a number of effective enrichment processes are available for analysis using gas chromatography and can be summarized as follows:
pentane extraction
adsorption onto solid materials using thermal desorption (purge and trap)
headspace techniques
Pentane extraction
The sample is cooled with ice and extracted using chilled pentane. Subsequently, the pentane phase is separated with a micro separator.
Purge and Trap
The purge gas, as a rule, the carrier gas of the gas chromatograph, passes through the exhaust vessel filled with the water sample. Through stripping, the volatile substances are driven out and then accumulate on the sorbent, e.g., Tenax. After the stripping process is complete, the substances are thermally desorbed by rapidly heating the adsorber column. They are then conveyed to the gas chromatograph through a heated transfer tube.
Headspace techniques
The static headspace method is an ideal technique for the analysis of the volatile substances found in water, due to the simple sample preparation and the substantial sensitivity of the analysis. A further advantage of this procedure is that particulate matter as well as other substances present in the sample with a low volatility and high molecular weight do not interfere with the analysis, since they are not carried by the steam into the headspace and are therefore do not reach the separation system. Moreover, the high degree of automation combined with the aforementioned short time required for sample preparation allows for a rapid, precise and user-friendly analysis for water samples.
Gas chromatography
For the gas chromatographic analysis, an electron capture detector (ECD) is employed due to its high selectivity and high sensitivity. If the ECD is combined with a flame ionization detector (FID), methylene chloride, benzene and its homologues can also be analyzed. With the aid of cryo-focusing, this method can be adapted to detect more volatile substances, such as vinyl chloride or chlorofluorocarbons.
This method describes how to determine 1,2-dichloroethane in drinking water through extraction, adsorption and gas chromatography.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
The method describes how to determine the content of tetrachloroethene and trichloroethene in drinking water through extraction and gas chromatography.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
Drinking water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
Vinyl chloride is determined using gas chromatography with detection by means of mass spectrometry (GC-MS) through application of the static headspace technique (HS). This method detects selected volatile organic compounds including chloroethene (vinyl chloride).