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Semicovalent

A pseudo salt is a compound that has some of the normal characteristics of a salt, but lacks certain others, notably the ionic lattice in the solid state and the property of ionizing completely in solution. The absence of these properties is due to the fact that the bonds between the metallic and nonmetallic radicals are covalent or semicovalent instead of polar. Because these salts do not ionize completely, they are also called weak salts. [Pg.1456]

This example shows a comparison of a noncovalently and a semicovalently imprinted MIP in MISPE. It also shows the development of an online coupled MISPE-HPLC system for environmental analysis of river water. [Pg.285]

Caro et al. made a noncovalent and a semicovalent MIP, respectively, for 4-nitrophenol (4-NP). Their purpose was to extract selectively 4-NP from river water in the presence of ten other phenolic pollutants. The MIPs were used in an online MISPE procedure employing dichloromethane as wash solvent. Figure 4 (Fig. 1 of the original) shows the experimental setup. The pump on the left is used to deliver the conditioning solutions, the sample, and the wash solvent. The two pumps on the right deliver the organic and the aqueous components of the HPLC... [Pg.285]

Figure 5 (Fig. 2 of the original) shows that with both MIPs the increase of wash solvent (dichloromethane) volume has led to cleaner eluates for 4-NP but also the peak area of 4-NP decreased substantially. The chromatograms of the eluates were cleaner when the non-covalent MISPE was used while the retention of 4-NP was better with the semicovalent MISPE. [Pg.286]

Interaction of Metal Atoms and Cluster with Covalent and Semicovalent Oxide Surfaces... [Pg.66]

The interaction of metals with the surfaces of covalent and semicovalent oxides has been studied to a much lesser extent than the ionic oxides commented above. Among the different materials which can be included in this section, SiC>2, ZnO and TiC>2 have without doubt received the most attention. Here, some of the most relevant aspects concerning the interaction of metals with these oxides will be revised. [Pg.66]

Figure 17 Schematic view of the imprinting of cholesterol nsing a semicovalent, sacrificial spacer approach. Figure 17 Schematic view of the imprinting of cholesterol nsing a semicovalent, sacrificial spacer approach.
A pictorial explanation for the ferromagnetic nature of the semicovalent exchange between filled and half-filled orbitals is given in Fig. 6.15. In the upper part, we can see how the subsequent electron transfer from py to b and from a to py leads to a... [Pg.200]

An estrone sensor was developed in Gao R. et al., 2011 by using a semicovalent imprinting strategy, which employed a thermally reversible covalent bond at the surface of silica coated CNTs. The synthesis of the nanocomposites involves silica shell deposition on the surface of CNTs, MIPs functionalized onto the silica surface, and final extraction of estrone by thermal reaction and generation of the recognition site. Authors state that the core-shell CNTs MIPs nanocomposites develofjed in this work can also be applied as a selective coating for electrochemical or quartz crystal microbalance sensors to monitor for estrone residue in environmental water... [Pg.197]

Caro et al. [155] s)mthesized three polymers using 4-chlorophenol (4-CP) as the template, following different protocols (noncovalent and semicovalent), and used different functional comonomers, 4-vinylpyridine (4-VP) and methacrylic acid (MAA). They have evaluated the selectivity of the polymers as MIPs sorbent in SPE coupled online to LC. They found out that the 4-VP noncovalent polymer was the only polymer that showed a clear imprint effect. This MIP also showed cross-reactivity for the 4-chloro-substituted phenols and for 4-NP from a mixture containing the 11 priority EPA phenolic compounds and 4-CP. The MIP was applied to selectively extract the 4-chloro-substituted compounds and 4-NP from river water samples. Figure 16.4 shows the chromatograms obtained by online MISPE with the 4-VP noncovalent 4-CP imprinted polymer of 10 mL standard solution (pH 2.5) spiked at 10 mg/L with each phenolic compoimd. [Pg.424]


See other pages where Semicovalent is mentioned: [Pg.87]    [Pg.350]    [Pg.287]    [Pg.256]    [Pg.277]    [Pg.277]    [Pg.279]    [Pg.1015]    [Pg.1015]    [Pg.76]    [Pg.201]    [Pg.123]    [Pg.69]    [Pg.228]    [Pg.138]    [Pg.139]    [Pg.480]    [Pg.159]    [Pg.447]    [Pg.26]    [Pg.26]    [Pg.943]    [Pg.943]    [Pg.212]    [Pg.256]    [Pg.277]    [Pg.277]    [Pg.277]    [Pg.279]    [Pg.279]    [Pg.2871]    [Pg.558]   
See also in sourсe #XX -- [ Pg.139 ]




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Semicovalent exchange

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