Separation methods for

Knowles P J and Meath W J 1987 A separable method for the calculation of dispersion and induction... 

Thorium, uranium, and plutonium are well known for their role as the basic fuels (or sources of fuel) for the release of nuclear energy (5). The importance of the remainder of the actinide group Hes at present, for the most part, in the realm of pure research, but a number of practical appHcations are also known (6). The actinides present a storage-life problem in nuclear waste disposal and consideration is being given to separation methods for their recovery prior to disposal (see Waste treati nt, hazardous waste Nuclear reactors, waste managet nt). 

These values, which match experience, suggest that distillation should be the preferred separation method for feed concentrations of 10—90%, but is probably a poor choice for feed concentrations of less than 1%. Techniques such as adsorption (qv), chemical reaction, and ion exchange (qv) ate chiefly used to remove impurity concentrations of <1%. 

An on-line concentration, isolation, and Hquid chromatographic separation method for the analysis of trace organics in natural waters has been described (63). Concentration and isolation are accompHshed with two precolumns connected in series the first acts as a filter for removal of interferences the second actually concentrates target solutes. The technique is appHcable even if no selective sorbent is available for the specific analyte of interest. Detection limits of less than 0.1 ppb were achieved for polar herbicides (qv) in the chlorotriazine and phenylurea classes. A novel method for deterrnination of tetracyclines in animal tissues and fluids was developed with sample extraction and cleanup based on tendency of tetracyclines to chelate with divalent metal ions (64). The metal chelate affinity precolumn was connected on-line to reversed-phase hplc column, and detection limits for several different tetracyclines in a variety of matrices were in the 10—50 ppb range. 

Research should continue on traditional separation methods. For example, there is a continuing need for more selective extraction agents for liquid-liquid and ion-exchange extractions. High-temperature processes that use liquid metals or molten salts as extraction agents should have potential in nuclear fuel reprocessing and... 

Poole, S. K., Poole, C. F. Separation methods for estimating octanol-water coefficients. J. Chromatogr. E 2003, 797, 3-19. 

G. Schill, H. Ehrsson, J. Vessaan, and D. Westerlund, "Separation Methods for Drugs and Related Organic Coapounds", Swedish Pharaaceutical Press, Stockhola, Sweden, 1983. 

One of the more formidable challenges to a chromatographer is that of developing a separation method for a sample that may contain several unknown components, including both ionizable and neutral molecules. A typical approach would be to choose a RP-HPLC column containing either... 

Carbohydrates play a major role in protein bioactivity, bioavailability, and antigenicity therefore, the understanding of the glycosylation of protein molecules is very important in the development of effective glycoprotein therapeutics.172 In recent years, there has been considerable activity in the development of simple, rapid, and reliable separation methods for the analysis of... 

Wall, D. B. Kachman, M. T. Gong, S. Hinderer, R. Paras, S. Misek, D. E. Hanash, S. M. Lubman, D. M. Isoelectric focusing nonporous RP HPLC A two-dimensional liquid-phase separation method for mapping of cellular proteins with identification using MALDI-TOF mass spectrometry. Anal. Chem. 2000, 72, 1099-1111. 

Jia, L., Liu, B., Terabe, S., Nishioka, T. (2004). Two-dimensional separation method for analysis of bacillus subtilis metabolites via hyphenation of micro-liquid chromatography and capillary electrophoresis. Anal. Chem. 76, 1419-1428. 

Many times an analyte must be derivatized to improve detection. When this derivatization takes place is incredibly important, especially in regards to chiral separations. Papers cited in this chapter employ both precolumn and postcolumn derivatization. Since postcolumn derivatization takes place after the enantiomeric separation it does not change the way the analyte separates on the chiral stationary phase. This prevents the need for development of a new chiral separation method for the derivatized analyte. A chiral analyte that has been derivatized before the enantiomeric separation may not interact with the chiral stationary phase in the same manner as the underivatized analyte. This change in interactions can cause a decrease or increase in the enantioselectivity. A decrease in enantioselectivity can result when precolumn derivatization modifies the same functional groups that contribute to enantioselectivity. For example, chiral crown ethers can no longer separate amino acids that have a derivatized amine group because the protonated primary amine is... 

Significant effort has been devoted to the development of separation methods for the post-BDS stage. Simple approach employing two phase separation methods like filtration or use of centrifugal forces have been studied as well as newer approaches including modification of biocatalyst to facilitate separation have been studied. Information has been obtained from patents as well as publications in open literature. 

Research on the development of separation methods for the multiphase reacting system led to the development of a three phase (oil, water, and a solid) separation process. A patent was awarded in 1998 in US [53] and subsequently in some other countries... 

Have a simple separation method for the catalyst from the products... 

Landrum, R.F., Nihart, S.R., Edie, B J., Gardner, W.S. (1984) Reverse-phase separation method for determining pollutant binding to Aldrich humic acid and dissolved organic carbon of natural waters. Environ. Sci. Technol. 18, 187-192. 

Uranium hydroxides, 25 430 Uranium iodides, 25 439 Uranium isotopes, 25 391, 392-394 alternative separation methods for, 25 417... 

The intra-cell processes are common to all PDF codes, and are treated the same in both Eulerian and Lagrangian PDF codes.8 On the other hand, inter-cell processes are treated differently in Eulerian PDF codes due to the discrete representation of space in terms of x . In PDF codes, fractional time stepping is employed to account for each process separately. Methods for treating chemical reactions and mixing are described in Section 6.9. Thus we will focus here on the treatment of inter-cell processes in Eulerian PDF codes. 

Gas chromatography (GC) has developed into the most powerful and versatile analytical separation method for organic compounds nowadays. A large number of applications for the analysis of surfactants have emerged since the early 1960s when the first GC papers on separation of non-ionics were published. The only major drawback for application of GC to surfactants is their lack of volatility. This can be easily overcome by chemical modification (derivatisation), examples of which will be discussed extensively in the following paragraphs. This chapter focuses on surfactant types, and in addition discusses some structural aspects of alkylphenol ethoxylates (APEOs) that are important for, as well as illustrative of, aspects of separation and identification that are linked to the complexity of the mixtures of surfactants that are involved. 

The PRISMA model274 and factorial experimental design were applied in the development of a one-dimensional overpressured layered chromatography separation method for the anti-neoplastic bis-indole alkaloids vincristine (102a), vinblastine (102b) and some derivatives275. 

The development of chiral separation methods for dipeptides is of relevance for purity controls, for checking racemization processes in peptide syntheses, and for the investigation of peptide and protein hydrolysates. Since their introduction as chiral... 

Some special approaches defined in the CE enantioseparation field can be found in References 37 and 38. In Reference 37, the authors tested four approaches to decrease the analysis time of a previously developed chiral separation method for amphetamine and its related compounds. The considered possibilities were (i) the short-end injection technique or (ii) increased electrical field combined with a capillary length reduction. 

Perrin, C., Vargas, M.G, Vander Heyden, Y., Maftonh, M., Massarf D.L. Fast development of separation methods for the chiral analysis of amino acid derivatives using capillary electrophoresis and experimental designs. J. Chromatogr. A 2000, 883, 249-265. 

The factors in Table 2 were selected from the chiral separation methods for propranolol, praziquantel, and warfarin. All factors were quantitative and their extreme levels situated symmetrically around the nominal. 

The factors in Table 3 were selected from a non-aqueous chiral separation method for timolol. One qualitative factor (1), i.e., the type of CE equipment, was examined. Two HPCE systems, A and B, with different software versions for equipment control, data acquisition, and handling were compared. Six quantitative factors ((2) till (7)), for which the extreme levels usually were situated symmetrically around the nominal, also were... 

Bitar, Y., Degel, B., Schirmeister, T., and Holzgrabe, U. (2005). Development and validation of a separation method for the diastereomers and enantiomers of aziridine-type protease inhibitors. Electrophoresis 26, 2313—2319. 

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