Static headspace gas chromatography

Miettinen, S.M. et al.. Effect of emulsion characteristics on the release of aroma as detected by sensory evaluation, static headspace gas chromatography, and electronic nose, J. Agric. Food Chem., 50, 4232, 2002. 

B. Kolb and L.S. Ettre, Static Headspace-Gas Chromatography. Theory and Practice, Wiley-VCH, New York, NY (1997). 

VOLATILE LIPID ANALYSIS UTILIZING STATIC HEADSPACE GAS CHROMATOGRAPHY... 

Kolb, B., Ettre, L.S. Static headspace-gas chromatography theory and practice, 2nd edn. Wiley, Hoboken, NJ (2006). ISBN 978-0-471-74944-8... 

Lissen J, Reitsma H, Cozijnsen J. Static headspace gas chromatography of acetaldehyde in aqueous foods and polythene terephthalate. Z Lebensm Unters Forsch 1995 201 (3) 253 5. 

The ability of flavonoids to enhance the resistance to oxidation and to terminate free-radical chain reactions in lipophilic systems can be monitored using low-density lipoproteins (LDL) as a model (Rice-Evans et al., 1996). The LDL oxidation is initiated either by copper or by a peroxyl radical [2,2 azobis(2-amidinopropane hydrochloride) (AAPH)] (Abuja et al., 1998). Hexanal liberated from the decomposition of oxidized n-6 polysaturated fatty acids in LDL may be determined by static headspace gas chromatography (Frankel and Meyer, 1998). Also, bleaching of P-carotene (Velioglu et al., 1998 Fukumoto and Mazza, 2000) and the tracing by HPLC (Fukumoto and Mazza, 2000) of malonaldehyde formed in lipid emulsion systems in the presence of iron (Tsuda et al., 1994) have been used to measure antioxidants in lipophilic systems. 

Ereeze-dried MlOO and M180 samples were rehumidified by storing them for at least 1 week in vacuum desiccators at relative humidities of 66 and 54%, respectively, at 25°C. The rehumidified samples were stored at 45, 50, and 60°C in order to study the release of aroma compoimds as a function of storage time. The release of benzaldehyde and ethyl acetate was analyzed using static headspace gas chromatography (EB 40 XC, Perkin Elmer, USA) and an electronic nose (Gas Detector MGD-1, Environics Ltd, Finland). 

LA. Wash, A.H. Al-Awadhi, Z.N. Al-Hatali, EJ. Al-Rayami, N.A.A. Katheeri, Rapid and sensitive static headspace gas chromatography-mass spectrometry method for the analysis of ethanol and abused inhalants in blood, J. Chromatogr. B, 799, 331-336 (2004). 

ASTM, D 4526 - Determination of Volatiles in Polymers by Static Headspace Gas Chromatography (2001)... 

Kolb, B. and Ettre, L. S., Static Headspace-Gas Chromatography Theory and Practice, Wiley-Interscience, New York, 1997. 

Figure 3.13. Schematic diagram of the balanced pressure sampling system for automated splitless static headspace gas chromatography with cryogenic trapping. V = solenoid valve in the carrier gas (CG) line V2 = solenoid valve for the purge gas and V3 solenoid valve for the cooling gas. (From ref. [142] Elsevier).

Liquid-liquid extraction has a counterpart for the determination of VOCs in the technique known as static or equilibrium headspace sampling. The technique is most often combined with the determinative step and is often referred to as static headspace gas chromatography, abbreviated HS-GC. The principles that underlie this technique will be outlined in this section. The decision to measure VOCs in the environment by either HS or purge and trap (P T or dynamic headspace) represents one of the ongoing controversies in the field of TEQA. This author has worked in two different environmental laboratories in which one used P T as the predominant technique to determine VOCs in the environment and the other used HS-GC. 

Bylaite., E., Meyer., Anne S., (2006). Characterization of volatile aroma compounds of orange juices by three dynamic and static headspace gas chromatography techniques. Eur Food Res Technol, 222,176-184. 

The technique of static headspace gas chromatography has great acceptance in the forensic field, especially for the determination of ethanol in biological samples (Macchia et al., 1995 Tagliaro et al., 1992), so most forensic laboratories in the world have this equipment and perform this analysis on a routine basis, but in many of these laboratories, equipment is exclusively employed to determine ethanol, even when this technique can be used to determine many other substances of toxicological interest, volatile substances, without major changes to the equipment (Seto, 1994), thus we can conclude that these laboratories do not exploit all the possibilities of the technique. 

The four most common approaches to quantitative static headspace gas chromatography calibration are external standard, internal standard, standard addition and multiple headspace extraction (MHE). The choice of technique depends on the type of sample being analyzed (Slack et al, 2003). 

External standard calibration in static headspace gas chromatography is best for analytes in liquid samples where the analytes are soluble in the matrix and the matrix has no effect on the analyte response. In these type of calibration is important to match the standard and sample matrix as closely as possible and to demonstrate equivalence in the response between the standards and the samples. The main difficulty with external standard calibration is that is does not compensate for any variability due to the gas chromatograph injection or due to variation in the analyte matrix. 

In the next sections, the mean applications of static headspace gas chromatography will be described, with an emphasis in methods that could be performed without extensive modification of the equipment commonly present in the forensic toxicology laboratories, in any case, analytical considerations will be discussed, from sampling, materials and reactants needed, analysis, to interpretation of results, method validation and the importance of these test in the legal media, will be reviewed. 

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