Carbohydrates cleanup

Materials of animal origin such as tissue, fat, milk, egg or blood contains usually relatively large amounts of fat, proteins and carbohydrates that need to be reduced during cleanup to allow enrichment of the analytes to be searched for. 

Of the 55 doctoral candidates whom Link supervised, over 30 worked partly or wholely on carbohydrates. Life in the laboratory was centered around the regular, Friday lab cleanup and research conference. To perform poorly in either activity was something to be avoided. In research conferences, Link aimed to help rather than em-... 

Samples to be analyzed can be of very complex nature (dairy products, fruit juice, etc.). Therefore, and provided that the preliminary steps—namely, sampling and moisture determination— have been properly attended to, the first important stage is sample preparation, which comprises extraction and cleanup. Once a sufficiently clean extract has been obtained, the carbohydrates therein may be separated prior to their detection and quantitation. 

Liquid-liquid extractions (13) permit the elimination of slightly polar molecules (phospholipids, fatty acids, etc) that may interfere in the HPLC determination of carbohydrates. Hence, for solid foodstuffs, some form of extraction will be required prior to the chromatographic procedure, and even in liquid food samples it may be necessary to modify the solvent composition of the liquid phase to make it compatible with the HPLC eluent. The major role of the extracting solvent is to obtain all of the carbohydrate present in the food sample dissolved in a liquid phase, be it for direct injection into the chromatograph or for subsequent cleanup stages prior to HPLC. 

Some factors will condition the choice of the cleanup procedure, namely (a) the extraction solvent used in the previous stage, (b) the concentration of the carbohydrates present in relation to potential interfering compounds, and (c) the complexity of the analyzed food. Additionally, the nature of these interferents and the need to minimize the loss of analyte during the cleanup will become key aspects to be considered. In any case, and regardless of the final method chosen, it is essential that the percentage recovery of the cleanup procedure be determined. The most frequently utilized procedures will be commented next. 

The first edition of Food Analysis by HPLC fulfilled a need because no other book was available on all major topics of food compounds for the food analyst or engineer. In this second edition, completely revised chapters on amino acids, peptides, proteins, lipids, carbohydrates, vitamins, organic acids, organic bases, toxins, additives, antibacterials, pesticide residues, brewery products, nitrosamines, and anions and cations contain the most recent information on sample cleanup, derivatization, separation, and detection. New chapters have been added on alcohols, phenolic compounds, pigments, and residues of growth promoters. 

Amino acids, fats carbohydrates Extraction, cleanup GC, HPLC, electrophoresis... 

The solvent extracts can be cleaned up by traditional column chromatography or by solid-phase extraction cartridges. This is a common cleanup method that is widely used in biological, clinical, and environmental sample preparation. More details are presented in Chapter 2. Some examples include the cleanup of pesticide residues and chlorinated hydrocarbons, the separation of nitrogen compounds from hydrocarbons, the separation of aromatic compounds from an aliphatic-aromatic mixture, and similar applications for use with fats, oils, and waxes. This approach provides efficient cleanup of steroids, esters, ketones, glycerides, alkaloids, and carbohydrates as well. Cations, anions, metals, and inorganic compounds are also candidates for this method [7],... 

Carbohydrates. Some families of organics, notably monosaccharides, have highly stylized features, such as rings and substituent orientation. These orientations need to be preserved (cleanup) or created (de novo). Fischer and Haworth projections, entirely different alternatives, are also subject to special rules of stereochemistry and chain form. 

Rouse, J. C. Vath, J. E. On-the-probe sample cleanup strategies for glycoprotein-released carbohydrates prior to matrix-assisted laser desorption—ionization time-of-flight mass spectrometry. Anal. Biochem. 1996, 238, 82-92. 

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