Fatty acids identification

Ha, Y.L., Grimm, N.K.. and Pariza, M.W. (1989) Newly recognized anticarcinogenic fatty acids. Identification and quantification in natural and processed cheeses. J. Agric. Food Chem., 37, 75-81. 

Sanches-Silva, A., Rodriquez-Bernaldo de Quiros, A., Lopez-Hemandez, J., Paseiro-Losada, P. 2004. Comparison between high-performance liquid chromatography and gas chromatography methods for fatty acid identification and quantification in potato crisps. J. Chromatogr. A. 1032, 7—15. 

Kunau, W.-H. Etommes, P. (1978) Eur. J. Biochem., 91, 533 44, Degradation of unsaturated fatty acids. Identification of intermediates in the degradation of cis-4-decenoyl-CoA by extracts of beef liver mitochondria. 

Brahmbhatt, V. V., C. J. Albert, D. S. Anbukumar, B. A. Cunningham, W. L. Neumann, and D. A. Ford. 2010. Omega -oxidation of alpha -chlorinated fatty acids Identification of alpha -chlorinated dicarboxylic acids. 285(53) 41255-69. 

Brahmbhatt, V.V., Albert, C.J., Anbukumar, D.S., Cunningham, B.A., Neumann, W.L. and Ford, D.A. (2010) Omega -oxidation of alpha -chlorinated fatty acids Identification of (alpha)-chlorinated dicarboxyhc acids. J. Biol. Chem. 285, 41255-41269. 

Abel et al. (1963) have suggested that the fatty acid composition of a particular microorganism might be a useful tool to aid in the classification of the organism. While there is no doubt that there may be some merit to this idea, their study aptly points out the complications to such an approach. First, it is quite clear that a number of their tentative assignments of fatty acid structures are incorrect. For example, the presence of major amounts of cyclopropane fatty acids in E. coli reported by a number of workers (Dauchy and Asselineau, 1960 Kaneshiro and Marr, 1961) is completely overlooked. Branched-chain fatty acids in various species of Bacillus and Micrococcus are also ignored. These errors illustrate the fact that fatty acid identification by gas-liquid chromatography, without ancillary analysis by independent... 

Oils are mixtures of mixed esters with different fatty acids distributed among the ester molecules. Generally, identification of specific esters is not attempted instead the oils are characterized by analysis of the fatty acid composition (8,9). The principal methods have been gas—Hquid and high performance Hquid chromatographic separation of the methyl esters of the fatty acids obtained by transesterification of the oils. Mass spectrometry and nmr are used to identify the individual esters. It has been reported that the free fatty acids obtained by hydrolysis can be separated with equal accuracy by high performance Hquid chromatography (10). A review of the identification and deterrnination of the various mixed triglycerides is available (11). 

Methyl Malonate.—This ester is an artificially prepared body, having a fruity odour, somewhat similar to the above-described esters of the fatty acids. It has the formula CH2(C02CHg)2, and boils at 181°. It may be prepared by treating potassium cyan-acetate with methyl alcohol and hydrochloric acid. On saponification with alcoholic potash it yields malonic acid, which melts at 132°, and serves well for the identification of the ester. 

McCapra, F., and Hysert, D. W. (1973). Bacterial bioluminescence — identification of fatty acid as product, its quantum yield and a suggested mechanism. Biochem. Biophys. Res. Commun. 52 298-304. 

The mechanisms of the metabolism and excretion of P-carotene are not clear, other than the identification of a number of partially oxidised intermediates found in plasma (Khachik et al., 1992). It is assumed that the carotenoids are metabolised in a manner analogous to the P-oxidation of fatty acids although there is no evidence for this. 

Alkaline hydrolysis (saponification) has been used to remove contaminating lipids from fat-rich samples (e.g., pahn oil) and hydrolyze chlorophyll (e.g., green vegetables) and carotenoid esters (e.g., fruits). Xanthophylls, both free and with different degrees of esterification with a mixture of different fatty acids, are typically found in fruits, and saponification allows easier chromatographic separation, identification, and quantification. For this reason, most methods for quantitative carotenoid analysis include a saponification step. 

Khachik, F. and Beecher, G.R., Separation and identification of carotenoids and carotenol fatty acid esters in some squash products by liquid chromatography. 1. Quantification of carotenoids and related esters by HPLC, J. Agric. Food Chem., 36, 929, 1988. 

Gau, W. et ah. Mass spectrometric identification of xanthophyll fatty acid esters from marigold flowers (Tagetes erecta) obtained by high performance liquid chromatography and Craig countercurrent distribution, J. Chromatogr., 262, 277, 1983. 

Craft DL, KM Madduri, M Eshoo, CR Wilson (2003) Identification and characterization of the CYP52 family of Candida tropicalis ATCC 20336, important for the conversion of fatty acids and alkanes to a,(o-dicarboxylic acids. Appl Environ Microbiol 69 5983-5991. 

Chloroform-methanol extracts of Borrelia burgdorferi were used for the identification of lipids and other related components that could help in the diagnosis of Lyme disease [58]. The provitamin D fraction of skin lipids of rats was purified by PTLC and further analyzed by UV, HPLC, GLC, and GC-MS. MS results indicated that this fraction contained a small amount of cholesterol, lathosterol, and two other unknown sterols in addition to 7-dehydrocholesterol [12]. Two fluorescent lipids extracted from bovine brain white matter were isolated by two-step PTLC using silica gel G plates [59]. PTLC has been used for the separation of sterols, free fatty acids, triacylglycerols, and sterol esters in lipids extracted from the pathogenic fungus Fusarium culmorum [60]. 

Labeque, R. and Marnett, L.J. (1988). Reaction of hematin with allylic fatty acid hydroperoxides identification of products and implications for pathways of hydroperoxide-dependent epoxidation of 7,8-dihydroxy-7,8-dihydrobenzo [a]pyrene. Biochemistry 27, 7060-7070. 

Camp, R.D., Mallet, A.L, Woolard, P.M., Brain, S.D., Kobza-Black, A. and Greaves, M.W. (1983). The identification of hydroxy fatty acids in psoriatic skin. Prostaglandins, 26, 431-447. 

To ensure microbial strains are viable and pure a suite of morphological, biochemical, and cytochemical tests are used to confirm characteristics specific to their taxons. A number of commercially available rapid identification kits are also employed for some common genera. In addition to these taxon specific tests, many of the cultures are tested for their fatty acid methyl ester (FAME) profiles using the commercial MIDI system. The FAME profiles can be compared to the MIDI database for species identification/confirmation purposes. The Biolog system, which yields a metabolic fingerprint of an organism, is another alternative for rapid identification. 

It is of interest to examine the development of the analytical toolbox for rubber deformulation over the last two decades and the role of emerging technologies (Table 2.9). Bayer technology (1981) for the qualitative and quantitative analysis of rubbers and elastomers consisted of a multitechnique approach comprising extraction (Soxhlet, DIN 53 553), wet chemistry (colour reactions, photometry), electrochemistry (polarography, conductometry), various forms of chromatography (PC, GC, off-line PyGC, TLC), spectroscopy (UV, IR, off-line PylR), and microscopy (OM, SEM, TEM, fluorescence) [10]. Reported applications concerned the identification of plasticisers, fatty acids, stabilisers, antioxidants, vulcanisation accelerators, free/total/bound sulfur, minerals and CB. Monsanto (1983) used direct-probe MS for in situ quantitative analysis of additives and rubber and made use of 31P NMR [69]. 

Cyclic oligomers of PA6 can be separated by PC [385,386] also PET and linear PET oligomers were separated by this technique [387]. Similarly, PC has been used for the determination of PEGs, but was limited by its insensitivity and low repeatability [388]. PC was also used in the determination of Cd, Pb and Zn salts of fatty acids [389]. ATR-IR has been used to identify the plasticisers DEHP and TEHTM separated by PC [390]. Although this combined method is inferior in sensitivity and resolution to modem hyphenated separation systems it is simple, cheap and suitable for routine analysis of components like polymer additives. However, the applicability of ATR-IR for in situ identification of components separated by PC is severely restricted by background interference. 

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