High-resolution gas chromatography HRGC

This unit describes those methods that can differentiate between enantiomers found in foods that contribute to their taste and aroma. These compounds are volatile odorants that are most easily analyzed using enantioselective high resolution-gas chromatography (HRGC). Other methods exist for the separation and analysis of chiral compounds, which include optical methods, liquid and planar chromatography, and electrophoresis, but for food volatiles, gas chromatography has evolved to the point where it is now the cornerstone for the most comprehensive analysis of volatile compounds. 

The extract of the volatiles is separated by high resolution gas chromatography (HRGC) and the odor of the compounds is assessed by sniffing the effluent of the GC column in parallel with the FID-detection. This technique allows the detection of odor-active volatiles, the determination of their odor qualities and, most important, the combination of these sensory data with an analytical parameter, the retention index (RI). In Figure 2, the results of... 

The techniques used for the separation of volatiles have been further improved. HPLC and high resolution gas chromatography (HRGC), the latter in combination with effluent sniffing, have been introduced into aroma analysis of bread (25). 

PCDE analyses can be performed by high resolution gas chromatography (HRGC) combined with low resolution mass spectrometry (LRMS) or using HRGC combined with high resolution mass spectrometry (HRMS). For example, a Hewlett Packard 5970 mass selective detector system, which is a qua-drupole mass analyzer, has been used as an LRMS instrument in Finnish studies [33, 57, 113, 114, 122-125, 139]. Compared to LRMS, HRMS is more sensitive, allows less sample cleanup, and eliminates interference more effec-... 

One of the most important analytical techniques used today is high-resolution gas chromatography (HRGC). The pesticide residues can be analyzed by specihe or multiresidue methods. When crops are treated with several pesticides, the use of a multiresidue method is preferable due the reduced cost and time of analysis. The methods of pesticides residue analysis usually present an initial step of extraction with a solvent which is not miscible with water, followed by a cleanup step and the analyte determination by gas chromatography. 

The application of gas chromatography (GC) to steroid analysis seems to have many difficulties due to then-insufficient volatility and thermolability. The development of high-resolution gas chromatography (HRGC) and various derivatization procedures enables the efficient separation of complex steroid mixtures for application in clinical, forensic toxicology, and natural products analysis. The development of low-cost MS detectors, in recent years, has also promoted the application of GC-MS systems for the analysis of the complex mixtures. 

High-performance liquid chromatography can be coupled, on-line, with high-resolution gas chromatography (HRGC) and MS. Gas chromatography allows the separation of chemically similar compounds from the previous separation provided by HPLC between the compounds with different polarities. 

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