General Parameters Affecting Retention

General Parameters Affecting Retention Eluent Flow Rate 

Shortening of separator columns is generally not feasible, because the aging process causes the separation efficiency to slowly diminish with time. An overly high resolution between two signals leads to unnecessarily long retention times. 

This can be prevented by choosing appropriate eluents and stationary phases. Under special circumstances, a drastic reduction in the retention time of an ion may be achieved by a separation on a shorter precolumn. 

The number of theoretical plates and, thus, the separation efficiency is determined by the length of the separator column. If two separator columns are used in series, the resulting enhancement of separation efficiency leads to a better resolution between ions with similar retention characteristics, with a corresponding increase in retention times. The separator column length also determines the ion-exchange capacity. An increase of the ion-ejodiange capacity via elongation of the separator column is recommended in all cases where the ion to be analyzed is present in an excess of another component. 

Shortening separator columns is generally not feasible because the alteration process causes the separation efficiency to slowly diminish with time. A resolution between two signals that is too high leads to unnecessarily long retention times. This can be prevented by choosing appropriate eluents and stationary phases, respectively. A drastic reduction in the retention time of an ion may be achieved in special circumstances by a separation on the shorter pre-column. 

2 Experimental Parameters Affecting Retention when Applying Suppressor 

While the parameters listed in Section 3.3.4.1 that determine the retention are fundamental in character, the parameters concerning the eluent discussed below depend on the detection system being used. This particularly applies to conductivity detection, which is possible directly or in combination with a suppressor system. These two modes of conductivity detection are fundamentally different and require eluents that not only differ with regard to their type but also to their concentrations and pH values, respectively. Therefore, the influence of these parameters on both modes is discussed separately for the most important detection system. 

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The second parameter that affects retention is the column temperature. In general, retention decreases with increasing temperature. The temperature influence on retention time can be correlated with the molecular size of the analyte and decreases in the order oligosaccharides < sugar alcohols <... 

It is thus clear that caprock thickness, which relates linearly to oil column retention capacity (Sales 1997) or rather caprock tightness (which is also affected by mineralogy/diagenesis), is an important parameter which must be risked in petroleum exploration and GOR predictions. This is especially important in basins where volumes of generated and expelled oil are likely to exceed the trap volumes, i.e. in overfilled basins like generally on the NOCS (cf Sales 1997). 

An alternative elassification of filter media is based on the minimum size of the trapped particles (see Table 3). Obviously, this classification provides only a general guideline to the types of media available. In fact, many process parameters (such as the particulate concentration, etc.) affect the retention behavior of... 

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