Capillary GC methods

A capillary GC method was also described for the determination of isoxsuprine and its metabolites in the urine of horses receiving a single dose of the drug [33]. 

S. Cram, How to Develop, Validate, and Troubleshoot Capillary GC Methods, American Chemical Society Short Course, 1996. 

Linolenic acid content must be low in order to provide maximum oxidative stability to the oil. This is why soybean and canola oil, which contain about 8% linolenic acid in the natural state, are hydrogenated to reduce their linolenic acid content to less than 2% determined by the capillary GC Method (2). Poor frying stability in sunflower oil comes primarily from the high level of hnoleic acid. Therefore, sunflower oil must also be hydrogenated to reduce its linoleic acid content to 35% or lower for industrial frying. Table 1 lists the analyses of the most commonly used industrial frying oils. 

Liquid soybean oil and liquid canola oil contain 8% linolenic acid. This makes both oils very prone to oxidation, especially in the frying application. Light hydrogenation can reduce the linolenic acid to less than 2% (measured by the capillary GC method). This makes the oils suitable for industrial frying of shelf-stable products. 

A capillary GC method was developed for the determination of 1,6-hexamethylenediamine (HAD) in hydrolyzed human urine.This method was based on a derivatization procedure using heptafluorobutyric anhydride. Capillary GC with thermionic specific detection (GC-TSD) made it possible to determine low concentrations (10 to 1000 /xg/1) of HAD in urine after oral... 

HPLC Analysis. HpIc analysis of the resistant exudate (Figure 1) showed that there are two major compounds which are known to be the C22 co5 (compound B) and C24 o>5 (compound I) unsaturated anacardic acids from earlier work, and a number of minor compounds of which only the C22 saturated (compound G) and C24 saturated (compound M) anacardic acids have previously been identified f2-61. Of the uncharacterized compounds, E and J are of particular interest, as they are present in similar quantities to the C22 and C24 saturated anacardic acids. This analysis is in good agreement with the capillary gc method used by Walters, who identified the four major anacardic acids and found them in similar quantities to those seen in the hpic trace. 

It was found that compound J, a major peak in the susceptible co-chromatographed with the C22 >5 (compound B) peak on gc and compounds H and N closely chromatographed with the C24 o>5 (compound I) peak. Thus it appears that the difference in results can be accounted for by the improved separation achieved on the hpic over the capillary gc method, and hence what were believed to be 0)5 anacardic acids in the susceptible exudate were really other compounds which happened to co-chromatograph with them. Such a problem is not encountered in the resistant exudate, as the 0)5 anacardic acids are by far the major components. 

MSTFA (A-methyl-A -trimethylsilyl-trifluoracetamide) as the silylation reagent. The same procedure can be applied to the determination of morphine, cocaine, and opium. Stromberg et al. introduced a system for the retrospective comparison of South Asian heroin this system consisted of an improved GC profiling method and computerized data retrieval. The peaks from the GC profile were investigated for abimdance, intensity, GC behavior (reproducibility), and correlations.The basis of the chemical analysis was a capillary GC method for the analysis of heroin trace impurities, which has been described in detail elsewhere. i2 ... 

Edkins and co-workers [34] have described a direct capillary GC method to monitor residual methylmethacrylate in polymethylmethacrylate. A short (5 m) crosslinked methyl silicone fused-silica capillary column with flame ionisation detection gave good separation efficiency and parts per million detection limits. Capillary gas-liquid chromatography was superior to packed column analysis (SP 1000) in terms of both analytical utility and ease of use. 

Initially, capillary GC methods attempted to simulate the packed column method with a run time of 45 min. The example in Figure 2.123 shows a capillary separation where the oven program is slowed down to keep the run time similar to the packed column method, and helium has been substituted for the original nitrogen carrier gas. However, with the increasing pressures on analysis time, and the flexibility within the EPA 610 method, it has been possible to greatly reduce run time by altering simple GC variables. 

To satisfy the Resource Conservation and Recovery Act (1977) and its amendment for hazardous and solid waste (1984), the 80(K) Series Methods have been designed to analyze solid waste, soUs, and groundwater. In particular, methods 8240/8260 require the use of a purge-and-trap device in conjunction with packed or capillary GC/MS, respectively, for the analysis of purgeable organic compounds. Methods 8250/8270 concern analyses for the less-volatile bases, neutrals, and acids by GC/MS after extraction from the matrix by an organic solvent. 

Capillary gc/ms, hplc, nmr, ir, and uv are all analytical methods used by the terpene chemist with a good Hbrary of reference spectra, capillary gc/ms is probably the most important method used in dealing with the more volatile terpenes used in the davor and fragrance industry (see Flavors and spices). The physical properties of density, refractive index, boiling point, melting point of derivatives, and specific rotation are used less frequendy but are important in defining product specifications. 

Residues of alachlor and acetochlor are determined by similar methods involving extraction, hydrolysis to the common aniline moieties, and separation and quantitation by reversed-phase FIPLC with electrochemical detection. The analytical method for acetochlor is included as a representative method for residue determination of alachlor and acetochlor in plant and animal commodities. Propachlor and butachlor residues, both parent and metabolite, are determined by similar analytical methods involving extraction, hydrolysis to common aniline moieties, and separation and quantitation by capillary GC. The analytical method for propachlor is included as a representative method. The details of the analytical methods for acetochlor and propachlor are presented in Sections 4 and 5, respectively. Confirmation of the residue in a crop or... 

The improvements to the first three steps of scheme 1 were accomplished using GC as a major analytical tool. A capillary GC internal standard method, described above, was used to monitor the first three steps of scheme 1. Figure 10 is a typical chromatogram of the internal standard method for step 1 of scheme 1. To follow a reaction, a known amount of internal standard was added to the reaction vessel. Aliquots were withdrawn at intervals and analyzed on GC. A graph of yield vs. reaction time was prepared to determine the optimum time for completion of the reaction. 

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