Gas chromatography calibration

WLR.dat Section 2.2.10 A set of peak area vs. concentration results of a gas chromatography calibration. Use with LINREG to test the effect of a weighting scheme. The originally estimated dependence of the standard deviation of determination vs. concentration is described by the equation SD = 100 + 5 X. 

Analytical Methods. Molecular weights were measured by summing the areas obtained by simulated distillation using gas chromatography, calibrated by injecting a series of standard aromatic compounds. 

The fatty acid methyl ester contents in the reaction mixture were determined using a Donam 6100 GC gas chromatograph (Donam, South Korea) equipped with an HP-INNOWAX capillary column (30m x 0.32imn x 0.5 pm) and an flame ionization detector. The column oven temperature was maintained at 210 °C for analysis. The injector and detector temperatures were set to 250 and 250 °C, respectively. Helium was utilized as a carrier gas. The gas chromatography calibration was conducted via the analysis of standard solutions of palmitic acid methyl ester, stearic acid methyl ester, oleic acid methyl ester, linoleic acid methyl ester, linolenic acid methyl ester, and erucic acid methyl ester. The internal standard was diluted in pyridine, as were the reaction mixture samples. The conversion was expressed as the percentage of fatty acid methyl esters generated relative to the theoretical maximiun quantity, based on the amount of original oils. In this paper, the conversion was expressed as the fatty acid methyl ester content or in accordance with conversion. 

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). 

The relative contents of ethylene oxide and propylene oxide in polyethylene-polypropylene glycols has been determined using combined pyrolysis-gas chromatography calibrated with polyethylene glycol and polypropylene glycol standards [65]. 

A4.4.2.1 Assemble the apparatus for vacuum distillation. Charge 0.5 to 1 L of pure, do n-hexadecane containing less than 0.1 % light contaminants as determined by gas chromatography. Calibrate the temperature and vacuum instruments as prescribed in Annex A6. 

It is important to note that simulated distillation does not always separate hydrocarbons in the order of their boiling point. For example, high-boihng multiple-ring-type compounds may be eluted earher than normal paraffins (used as the calibration standard) of the same boiling point. Gas chromatography is also used in the ASTM D 2427 test method to determine quantitatively ethane through pentane hydrocarbons. 

Historically, measurements have classified ambient hydrocarbons in two classes methane (CH4) and all other nonmethane volatile organic compounds (NMVOCs). Analyzing hydrocarbons in the atmosphere involves a three-step process collection, separation, and quantification. Collection involves obtaining an aliquot of air, e.g., with an evacuated canister. The principal separation process is gas chromatography (GC), and the principal quantification technique is wdth a calibrated flame ionization detector (FID). Mass spectroscopy (MS) is used along with GC to identify individual hydrocarbon compounds. 

Transfer all samples and calibrant standards to gas chromatography (GC) vials. Inject samples on to the GC column in the following order 10 ugmL standard, sample, sample, 5 ugmL standard, sample, sample, 2 pgirtL" standard, etc. 

The reaction mixture is sampled after each reaction cycle and analyzed for purity, reaction progress, and the presence and amount of by-products (if any) formed. Analysis is by gas chromatography (HP 5890 Series II Phenomenex Zebron ZB-1 capillary column, Phenomenex Cat. No. 7HK-G001-36) with flame ionization detection in order to quantify the by-product impurities. The quantity of the byproducts is determined using an external standard calibration method. 

Szathmary and Luhmann [50] described a sensitive and automated gas chromatographic method for the determination of miconazole in plasma samples. Plasma was mixed with internal standard l-[2,4-dichloro-2-(2,3,4-trichlorobenzyloxy) phenethyl]imidazole and 0.1 M sodium hydroxide and extracted with heptane-isoamyl alcohol (197 3) and the drug was back-extracted with 0.05 M sulfuric acid. The aqueous phase was adjusted to pH 10 and extracted with an identical organic phase, which was evaporated to dryness. The residue was dissolved in isopropanol and subjected to gas chromatography on a column (12 m x 0.2 mm) of OV-1 (0.1 pm) at 265 °C, with nitrogen phosphorous detection. Recovery of miconazole was 85% and the calibration graph was rectilinear for 0.25 250 ng/mL. 

Merritt, D. A., Brand, W. A. and Hayes, J. M. (1994) Isotope ratio monitoring gas chromatography mass spectrometry methods for isotopic calibration. Organic Geochemistry 21, 573 583. 

Kolb, B., Welter, C., Bichler, C. (1992) Determination of partition coefficients by automatic equilibrium headspace gas chromatography by vapor phase calibration. Chromatographia 34, 235-240. 

Dunnivant, F.M. and A.W. Elzerman. 1988. Determination of polychlorinated biphenyls in sediments, using sonication extraction and capillary column gas chromatography-electron capture detection with internal standard calibration. Jour. Assoc. Offic. Anal. Chem. 71 551-556. 

Instrumental resolution, 23 132 Instrumentation. See also Instruments calibration of, 21 161 capillary electrophoresis, 4 633 composition measurement, 11 785 for fermentation, 11 36—40 flow rate, 11 781-783 flow visualization, 11 785-786 fluid mechanics, 11 781-786 food processing, 12 87-88 gas chromatography, 4 611 6 413-414 infrared spectroscopy, 14 225-228 23 137-138... 

The first two groups have been collectively termed as Gas Chromatography .Its phenomenal growth at almost logarithmic pace may be attributed to its unparalleled potential in resolving components of a complex mixture. Gas chromatography fundamentally is a separation technique that not only essentially provides prima facie indentification of a compound but also caters for quantitative estimation after due calibration. 

Off-gas analysis is routinely carried out either by mass spectrometry or by gas chromatography (GC), in contrast with traditional infrared and paramagnetic off-gas analyzers which are maintenance intensive and have slow response times and significant calibration drifts. 12 ... 

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