Modern extracts

The flavour and modern phytopharmaceutical industries have made big changes to the traditional pharmaceutical extraction processes. Whereas ethanol was really the only significant solvent apart from water used by the traditional pharmaceutical extractors, solvents such as hexane and acetone have been used by flavour companies to make soft-extract oleoresins for natural flavour components. Sub- and supercritical carbon dioxide and also some fluorohydrocarbons are now used to produce some very high-quality extracts. Modern concentration and drying processes such as reverse osmosis, spray-drying and freeze-drying 

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Turner, C., Overview of modem extraction techniques for food and agricultural samples, in Modern Extraction Techniques Food and Agricultural Samples, ACS Symposium Series, No. 926, Turner, C., Ed., Washington, D.C., 2006, chap. 1. 

C.S. Eskilsson, R. Davidson and L. Mathiasson, Harmful azo colorants in leather. Determination based on their cleavage and extraction of corresponding carcinogenic amines using modern extraction techniques. J. Chromatogr.A, 955 (2002) 215-227. 

Hyphenation of Modern Extraction Techniques to LC-NMR for the Analysis of Geometrical Carotenoid Isomers in Functional Food and Biological Tissues... 

Soxhlet extraction and automated Soxhlet extraction are described in this section. Soxhlet extraction was named after Baron Yon Soxhlet, who introduced this method in the mid-nineteenth century. It had been the most widely used method until modern extraction techniques were developed in the 1980s. Today, Soxhlet is still a benchmark method for the extraction of semivolatile organics from solid samples. Automated Soxhlet extraction (Soxtec being its commercial name) offers a faster alternative to Soxhlet, with comparable extraction efficiency and lower solvent consumption. 

The impact of the extraction conditions using various solvents on the recoveries has never been studied in detail, and the results have never been compared. The introduction of modern extraction methods, such as microwave-assisted extraction, supercritical fluid extraction, and solid-phase extraction, probably will improve the efficiency of extraction, even in the instance of unstable pigments and pigment mixtures. The majority of TLC separations were carried out on traditional silica layers. As the chemical structures and, consequently, the retention characteristics of pigments are highly different, a wide variety of eluent systems has been employed for their separation, consisting of light petroleum, ethyl formate, ethyl acetate, benzene, toluene, chloroform, methanol, n-butanol, formic or acetic acid, and so forth. 

There are numerous modern extraction techniques that improve the reliability of the sampling process a silica bonded phase should be used to carry out a solid-phase microextraction of aromatic hydrocarbons such as benzene, toluene, m-xylene, and o-xylene 58 A derivatization step has been proposed59 to improve the separation process. The derivatization step assures the best reliability of fatty acids sampling (in water/air). Head space solid-phase microextraction (HS-SPME) has been employed for sampling of volatile components. This separation process can be successfully used for quality control of herbal medicines and other formulations containing herbal extracts.60... 

Modern Extraction Techniques Food and Agricultural Samples... 

Identification of Volatile Compounds in Shiitake Mushrooms Using Modern Extraction Techniques... 

Chemisch-technischer Produkte, Berlin, 1931 W, R. Heu-mann. Bulletin on Narcotics IX, 34 (1957). Modern extraction process using ion-exchange chromatography Achor,... 

Once a method has been developed including a quantitative collection step combined with an exhaustive extraction process, it is necessary to test the method s wider applicability. This is unfortunately a critical step (and applies to all extraction techniques) since it is impossible to know the total amount of a certain analyte present in a real-world sample. There are certain strategies that should be adopted to verify the quantitativeness of the method. The applied extraction conditions can be altered by increasing the temperature for matrices known to bind analytes hard or increase pressure for matrices known to contain bulk levels of analytes. If this improves extraction recoveries, the method is not final. Another important option is to compare SFE recoveries with recoveries obtained with conventional extraction procedures (Soxhlet) or other modern extraction techniques (PFE). If the same results are achieved, it is likely that the developed method is quantitative. It is also possible to reextract the SFE residual with another extraction method, thereby, detecting remaining analyte residues in the matrix. A third alternative is to utilize certified reference materials where... 

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