Extraction, sample gardener

In the laboratory, each soil sample (40 g) was transferred to a centrifuge bottle. Since the original purpose of the soil collection was to monitor specific organic compounds in the sludge-amended garden soils, a set of surrogate compounds was added to the soil prior to extraction to assess the extraction and cleanup recovery. 

Figure 7.13. Apparatus for extracting organic solutes from water. Apparatus for extracting organic solutes from finished drinking water samples. (A) standard garden hose coupling, (B) Teflon washer, (C) 1/2 inch...

As an alternative to traditional solvent extraction methods, the extraction by supercritical (SC) fluids has been used in tocol analysis. This is an environmentally friendly technique as little or no solvents are used. Extraction parameters, e.g. temperature and fluid density, are easily optimized and managed, and as the extraction is fast it is thus suitable for routine work with many samples. SC carbon dioxide has been used to extract tocols from barley (Fratianni et al, 2002), dried bay leaves (Gomez-Coronado et al, 2004), and garden cress seeds (Diwakar et al, 2010). Extractions were carried out in single or multiple steps and with different fluid densities controlled by extraction pressures. Tocol yields from barley were 5% and 14% less than by Soxhlet and chloroform-methanol extractions (Fratianni et al, 2002), yields from garden cress seeds were 26% less than by Soxhlet extraction (Diwakar et al, 2010), and a- and y-tocopherol yields from dried bay leaves were 22% and 40% less than by acetone extraction (Gomez-Coronado et al, 2004). Despite lower recoveries of tocols, the SC carbon dioxide extraction methods were considered comparable to the classical extraction methods (Fratianni et al, 2002). 

The most thorough examination of a species in the Picrodendraceae was conducted by Koike, Ohmoto, and coworkers on P. baccatum (36,46,53-56,77,78). This tree is endemic to the West Indies. The plants investigated by the authors were harvested in the Botanical Garden of Bogor, Indonesia in 1986. In the next 15-20 years this Japanese group isolated 9 monolactone sesquiterpenes and 19 norditerpene picrotoxanes from this plant material. At first, these researchers examined a relatively small sample of the bark of the tree to determine the structural type of the toxins. Thus, 1.2 kg of dried bark were extracted successively with n-hexane. 

The other field of application of the different methods of analysis is the cultivated opium plant (P. somniferum L.) itself, which produces TB. It has a Imig cultivatiOTi history worldwide and there are many varieties having various colors and shapes of flowers, shapes of capsules, and alkaloid composition and content. Despite the strict control of the plants, seeds of P. somniferum have been imported and sold as an ornamental gardening flower for which to control illegal cultivation of the plants, rapid and reliable extraction methods of opium alkaloids fi om many plant samples are required. CZE-UV has been employed for the analysis of opium samples and poppy straws [111, 113] and in presence of p-CD by CE-CD-UV in Iranian opium poppy plants [114]. Other detection systems such as MS and ECL with the same separation technique have been employed for the analysis of illicit samples [131] and Chinese traditional medicine opium poppy samples [124], respectively. 

The first applications of MAE dealt with the extraction of essential oils from plant products was reported in 1994 [45]. Microwave heating was used for the isolation of essential oils. Solvent free microwave extraction (SEME) involves microwave heating involves dry distillation at atmospheric pressure for the isolation of the essential oils in fresh plant materials. SFME was used to obtain essential oils from different spices such as ajowan, cumin, and star anise [46,47], and three different aromatic herbs (basil, garden mint, and thyme) [47]. Using the SFME method, either solvent or water is needed if fresh plant material is used. However, in case of dry plant material, the sample should be rehydrated by soaking in water before the extraction. 

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