Cost-effective extraction method

Reducing the cost of the PHA recovery method is not the only factor to be considered during downstream processing. The requirement of a simpler operation and eco-balanced system, whilst maintaining material quality, is also essential for the establishment of a cost-effective extraction method [2,3]. This is even more significant when it comes to large-scale PHA extraction as a simpler operation ensures lower energy input and a shorter process time. An eco-balanced... 

The method is very effective for the separation of dissolved components and enables the production of high-purity products, in addition to its advantages of being a low-cost and simple method. Liquid—liquid extraction is performed continuously using simple equipment, which can be completely automated and does not require constant labor and service. 

This cycle of vaporisation of the solvent, condensation, extraction, and vacuum-filtration may be repeated any number of times in a solid-fluid serial extractor. The occurrence of an extractive material fluid bed as a result of the flow of boiling hot vapour provides for effective extraction, while pressure filtration provides for short cycle times. This functional principle makes it possible to achieve filtration pressures which are 50-100 times more effective than when using the Soxhlet method, where only the low hydrostatic pressure of the extractive fluid operates. Solid-fluid-vortex extraction according to the proprietary FEXTRA (Feststoff Extraktion) principle is low cost. 

It is apparent from Chapter 3 that new sample preparation technologies generally are faster, more efficient and cost effective more easily automated and safer use smaller amounts of sample and less organic solvent provide better recovery and meet or exceed precision and accuracy compared to traditional sample preparation techniques. Conventional methods of the analysis of additives in polymers are mostly based on the separation of the polymer matrix and additives by means of extraction. Many extraction principles are... 

Table 10.32 is a shortlist of the characteristics of the ideal polymer/additive analysis technique. It is hoped that the ideal method of the future will be a reliable, cost-effective, qualitative and quantitative, in-polymer additive analysis technique. It may be useful to briefly compare the two general approaches to additive analysis, namely conventional and in-polymer methods. The classical methods range from inexpensive to expensive in terms of equipment they are well established and subject to continuous evolution and their strengths and deficiencies are well documented. We stressed the hyphenated methods for qualitative analysis and the dissolution methods for quantitative analysis. Lattimer and Harris [130] concluded in 1989 that there was no clear advantage for direct analysis (of rubbers) over extract analysis. Despite many instrumental advances in the last decade, this conclusion still largely holds true today. Direct analysis is experimentally somewhat faster and easier, but tends to require greater interpretative difficulties. Direct analysis avoids such common extraction difficulties as ... 

A variety of online solid extraction devices and applications have been developed for bioanalysis. Many are easy to build in laboratories or commercially available. Unlike offline methods, minimal operator intervention is needed for daily sample analysis after online applications are set up, so the approach is both labor- and cost-effective. The technique can also minimize errors arising from manual operations, eliminate potential inconsistencies caused by different operators, and provide accessibility of LC/MS/MS applications to laboratories that have minimal analytical expertise. 

Einally, acmal detection of the analyte has to be done by choosing a cost-effective and reliable method. In general, the functional groups of many of the PPCPs can render their extraction from water and measurement with GC and HPLC difficult. Eurthermore, the environmental matrices such as soil and sediments also impose significant interference in the analysis of these compounds. To that effect, no single method or piece of equipment can measure all the compounds of concern. Individual laboratories typically have to optimize the methods. 

Based on a cost analysis performed at the U.S. Department of Energy s Hanford site, in Richland, Washington, PSVE was found to be a cost-effective method for remediation of soils containing lower concentrations of volatile contaminants. PSVE used on wells that average 10 standard cubic feet per minute (scfm) airflow rates was found to be more cost-effective than active soil vapor extraction for concentrations below 500 parts per million (ppm) by volume of carbon tetrachloride. For wells that average 5 scfm, PSVE is more cost effective below 100 ppm (D14489S, p. iii). For further details of this analysis, refer to Table 1. 

Cost effective compared to current remediation technologies such as steam injection, bioventing, soil vapor extraction (SVE), and pump-and-treat methods. 

Quest Diagnostics have established a routine system for testosterone, which has now replaced their other methods of analysis (Goldman et al., poster, US Endocrine Society meeting, San Diego, 2005). The analysis is carried out on a Thermofinnigan TSQ Quantum Ultra operated with an APCI source in the positive-ion mode. They use two transitions, 289—>109 and 289—>97, for the analyte and 294—>112 and 294—> 99 for the 2H5-labeled internal standard. On-line extraction and short retention times allow them to assay several thousand samples per month per instrument, making it cost-effective in spite of the high cost of instrumentation. 

Organic substances can be extracted from aqueous samples by solid-liquid (known as solid phase) extraction. The process is simple, fast, and cost effective in comparison to LLE. In addition, the analysis can be carried out using a smaller volume of sample. By using a suitable capillary column, a detection level comparable to LLE-packed column could be readily attained. The method requires a... 

As mentioned, asymmetrically pure compounds are important for many applications, and many different strategies are pursued. However, in spite of many methods being developed, the classic resolution technique of diastereomeric crystallization is still preferentially used to prepare optically active pure compounds in bulk quantity. Crystallization is commonly used in the last purification steps for solid compounds because it is the most economic technique for purification and resolution. Attempts to achieve crystallization after completed reaction without workup and extraction is called a direct isolation process. This technique can be cost-effective even though the product yield obtained is lower. Special conditions may be needed in this case, and the diastereomers can be classified into two types diastereomeric salts and covalent diastereomeric compounds, respectively. Diastereomeric salts can, for example, be used in the crystallization of a desired amine from its racemic mixture using a chiral acid. Covalent diastereomers can, on the other hand, be separated by chromatography, but are more difficult to prepare. Another advantage of crystallization is the possibility of combining in situ racemi-zation reactions and diastereomeric formation reactions to get the desired pure compounds. This crystallization-induced resolution technique is still under development because of its requirements for optimized conditions [55, 56],... 

---