Retention organic polymer-based materials

For these three materials, covalent bonding technologies cannot be used. With silanes, mixed anhydrides are formed lacking in hydrolytic stability. Coating with organic polymers [32] is the way to go. A bonded phase based on zirconia has been studied widely [43]. Method development strategies established with silica-based RP cannot be transferred to an RP bonded on zirconia. Selectivity is dependent, e.g., on the type of buffer used. Anions in the mobile phase influence retention. The kinetics of analyte interaction with the different active sites may lead to reduced efficiencies. 

The dynamic tracer pulse technique used in this work facilitates the study of BV and how BV might be altered because of high levels of organic compounds or humidity. Based on competitions of the various, selected probes, cursory information about surface sites can be obtained for a prospective adsorbent such information is especially useful for multifunctional polymers. This technique can also permit the fine tuning of the environmental collection strategy through the examination of retentions on mixed adsorbents or multiple adsorbent beds. The use of dynamic TPC with the polyimides demonstrated that these materials are more sensitive, in terms of BV of the tested probe molecules, to the effects of humidity than is Tenax-GC. 

Polystyrene/divinylbenzene-based ion-exclusion columns are also offered by Hamilton Co. (Reno, NV, USA) under the trade name PRP-X300. This is a 10-pm material with an exchange capacity of 0.2 mequiv/g [4], It is obtained by sulfonation of PRP-1, a macroporous PS/DVB polymer with reversed-phase properties. Fig. 4-2 shows the separation of various organic acids on this stationary phase. Dilute sulfuric acid was used as the eluent. The much higher retention of succinic acid compared to acetic acid reveals that the retention of organic acids is chararcterized, apart from reversed-phase effects, by the formation of hydrogen bonds. 

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