Separation mechanisms desorption effect

A useful classification of the various LC techniques is based on the type of distribution mechanism applied in the separation (see Table 1.2). In practice, most LC separations are the result of mixed mechanisms, e.g., in partition chromatography in most cases contributions due to adsorption/desorption effects are observed. Most LC applications are done with reversed-phase LC, i.e., a nonpolar stationary phase and a polar mobile phase. Reversed-phase LC is ideally suited for the analysis of polar and ionic analytes, which are not amenable to GC analysis. Important characteristics of LC phase systems are summarized in Table 1.3. 

As seen in reaction (6.5.3) photogenerated holes are consumed, making electron-hole separation more effective as needed for efficient water splitting. The evolution of CO2 and O2 from reaction (6.5.6) can promote desorption of oxygen from the photocatalyst surface, inhibiting the formation of H2O through the backward reaction of H2 and O2. The desorbed CO2 dissolves in aqueous suspension, and is then converted to HCOs to complete a cycle. The mechanism is still not fully understood, with the addition of the same amount of different carbonates, see Table 6.2, showing very different results [99]. Moreover, the amount of metal deposited in the host semiconductor is also a critical factor that determines the catalytic efficiency, see Fig. 6.7. 

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