HEADSPACE CHROMATOGRAPHY

Determination of 1,4-Dioxane in Ether Sulfates by Headspace Chromatography... 

Hauff, K., Fischer, R.G., and Ballschmiter, K. Determination of C1-C5 alkyl niPates in rain. snow, white frost, lake, and tap water by a combined codistillation headspace chromatography technique. Determination of Henry s law constants by head-space GC, Chemosphere, 37(13) 2599-2615, 1998. 

Suitheimer C, Best R, Sunshine I. 1982. Volatiles by headspace chromatography. In Sunshine I, Jatlow PI, eds. Methodology for Analytical Technology. Volume II. Boca Raton, FL CRC Press Inc., 1-9. 

Table D2.2.1 Troubleshooting Guide for Headspace Chromatography of Lipid Oxidation Products... 

Table D2.2.1 lists a number of problems that might arise in headspace chromatography of lipid oxidation products, along with their possible causes and solutions.

For a volatile solute, the vapor pressure can be measured. This can be done as a function of the solute concentration at constant surfactant concentration. The activity of the solute is P/P° where P° is the vapor pressure of the pure solute. Two sets of data are required, the activity (or vapor pressure) of the solute in water and the activity (or vapor pressure) of the solute in aqueous surfactant solution. The horizontal distance between these two curves is a direct measure of the solubilized solute. The experimental techniques used for this purpose are headspace chromatography as used by Hayase and Hayano and Spink and Colgan, ° or the final equilibrium pressure over a solution containing a known quantity of volatile liquid can be measured. The latter method has been developed by Tucker and Christian. This method has the added advantage of providing an easy... 

Another version of this static headspace chromatography is what has been called by Kolb multiple headspace extraction (MHE) chromatography. This is a multi-step injection... 

Volatile matter content in polymers by headspace chromatography ASTM D4526... 

Activity coefficients at infinite dilution of a solute (1) in a solvent phase (3) are invaluable for the development of correlative and predictive thermodynamic models and for the selection of solvents for extractive/ azeotropic distillation, liquid-liquid extraction and solvent-aided crystallization. The experimental determination of can be achieved through the use of techniques such as ebulliometry [60], headspace chromatography [61],... 

The current pool of y 3 data for ionic liquid-organic solute interactions exceeds those obtained by alternative techniques such as headspace chromatography, dilutor and the static technique. As mentioned previously, experimental investigations on ionic liquids from an industrial perspective have largely been guided by separation problems of interest to the chemical and petrochemical industries such as alkane-aromatic, cyclo-alkane-aromatic and alkane-alkene mixtures. In this regard, selectivities at infinite dilution (5j ) are presented in Table 3 for (i) n-hexane-benzene, (ii) cyclohexane-benzene and (iii) n-hexane-l-hexene separations in various ionic liquid and commercially significant solvents. 

Quantitative Analysis of Trichloroethylene, Trichloroethanol and Trichloroacetic Acid in Blood and Urine by Headspace Chromatography Appl. Headspace Chromatogr., [GC Headspace Symp.], 1978 (Pub. 1980) 133-139 CA 93 38637w... 

Briihl, L. and Fiebig, H-J. 2005. Assistance of dynamic headspace chromatography for panel sensory evaluation. Riv. Ital. Sostanze Gr. 82 291-297. 

Another version of this static headspace chromatography is what has been called by Kolb multiple headspace extraction (MHE) chromatography. This is a multistep injection technique which was alluded to in the Suzuki publication and more openly developed by McAuliffe. The principle of this method is the following. After the first extraction has been made and the aliquot injected, the gas phase is removed by ventilating the vial and re-establishing the thermodynamic equilibrium. The equilibrium between the analyte in the solid or liquid phase and the gas phase will be displaced each time. After n extractions the analyte content in the liquid or solid phase becomes negligible. It is flien sufficient to sum the peak areas obtained for each extraction (which decrease exponentially) and, from an external calibration curve, determine the amount of RS in the substance. 

Blood and urine are most often analyzed for alcohol by headspace gas chromatography (qv) using an internal standard, eg, 1-propanol. Assays are straightforward and lend themselves to automation (see Automated instrumentation). Urine samples are collected as a voided specimen, ie, subjects must void their bladders, wait about 20 minutes, and then provide the urine sample. Voided urine samples provide the most accurate deterrnination of blood alcohol concentrations. Voided urine alcohol concentrations are divided by a factor of 1.3 to determine the equivalent blood alcohol concentration. The 1.3 value is used because urine has approximately one-third more water in it than blood and, at equiUbrium, there is about one-third more alcohol in the urine as in the blood. 

Trihalomethanes. Wherever chlorine is used as a disinfectant in drinking-water treatment, trihalomethanes (THMs) generaUy are present in the finished water. The THMs usuaUy formed are trichloromethane (chloroform), bromodichloromethane, dibromochloromethane, and tribromomethane (bromoform). There are four main techniques for the analysis of THMs headspace, Hquid— Hquid extraction (Ue), adsorption—elution (purge—trap), and direct aqueous injection. The final step in each technique involves separation by gas—Hquid chromatography with a 2 mm ID coUed glass column containing 10 wt % squalene on chromosorb-W-AW (149—177 p.m (80—100 mesh)) with detection generaUy by electron capture. 

Solid-phase microextraction (SPME) was used for headspace sampling. The FFA were extracted from the headspace with PA, Car/PDMS, and CW/DVB fibers. It was examined whether addition of salt (NaCl) and decreasing the pH by addition of sulphuric acid (H SO ) increased the sensitivity. FFA were analyzed using gas chromatography coupled to mass spectrometry in selected ion monitoring. 

Principle. The content of 1,4-dioxane in ether sulfates is determined by headspace gas chromatography according to the standard additions method. The method is suitable for all ether sulfates and gives reliable results independent of chain length distribution and water content. 

Deveaux M, Huvenne J-P. 1987. Identification of solvents of abuse using gas chromatography/fourier transform infrared spectrometry after headspace sampling. Chromatographia 23 626-630. 

Dietz EA Jr, Singley KF. 1979. Determination of chlorinated hydrocarbons in water by headspace gas chromatography. Anal Chem 51 1809-1814. 

Entz RC, Thomas KW, Diachenko GW. 1982. Residues of volatile halocarbons in foods using headspace gas chromatography. J Agric Food Chem 30 846-849. 

Ramsey JD, Flanagan RJ. 1982. Detection and identification of volatile organic compounds in blood by headspace gas chromatography as an aide to the diagnosis of solvent abuse. J Chromatogr 240 423-444. 

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. 

Bianchi, F., Careri, M., and Musci, M. (2005). Volatile norisoprenoids as markers of botanical origin of Sardinian strawberry-tree (Arbutus unedo L.) honey Characterisation of aroma compounds by dynamic headspace extraction and gas chromatography-mass spectrometry. Food Chem. 89,527-532. 

The concept of SPME was first introduced by Belardi and Pawliszyn in 1989. A fiber (usually fused silica) which has been coated on the outside with a suitable polymer sorbent (e.g., polydimethylsiloxane) is dipped into the headspace above the sample or directly into the liquid sample. The pesticides are partitioned from the sample into the sorbent and an equilibrium between the gas or liquid and the sorbent is established. The analytes are thermally desorbed in a GC injector or liquid desorbed in a liquid chromatography (LC) injector. The autosampler has to be specially modified for SPME but otherwise the technique is simple to use, rapid, inexpensive and solvent free. Optimization of the procedure will involve the correct choice of phase, extraction time, ionic strength of the extraction step, temperature and the time and temperature of the desorption step. According to the chemical characteristics of the pesticides determined, the extraction efficiency is often influenced by the sample matrix and pH. 

B. Kolb, "Applied Headspace Gas Chromatography", Heyden, London, UK, 1980. 

B. V. Ioffe and A. G. Viltenberg, "Headspace Analysis and Related Methods in Gas Chromatography", Hiley, New York, NY, 1984. 

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