System suitability theoretical plate number

System suitability specifications and tests, Capacity factor (k ), Preci-sion/injector repeatability (RSD), Relative retention (a), Resolution (Rs),Tailing factor (T),Theoretical plate number (N)... 

In the System Suitability section, different parameters are described which can be applied in order to check the behavior of the CE system. The choice of the appropriate parameters depends on the mode of CE used. The system suitability parameters include retention factor (k) (only for MEKC), apparent number of theoretical plates (N), symmetry factor (Af), resolution (Rs)> Rtea repeatability, migration time repeatability, and signal-to-noise ratio. Practical equations to calculate different system suitability parameters from the electropherograms are presented, which are also included in Table 3. 

Other results obtained from the ruggedness test are the definition of optimized method conditions for the factors and of system suitability criteria for a number of responses. System suitability parameters [6,17] are defined as an interval in which a response can vary for a rugged method. The system suitability criteria are the range of values between which a response (e.g. retention time, capacity factor, number of theoretical plates, resolution) can vary without affecting the quantitative results of the analysis. For instance, a design is performed and the retention time of the main substance varies between 200 s and 320 s without affecting the quantitative determination of the substances. The system suitability criteria for the retention time is then defined as the interval 200 s - 320 s. 

System suitability parameters [6,17] are defined as an interval in which a response (e.g. retention time, resolution, number of theoretical plates) are allowed to vary for a robust method. They can be derived from the minimal and maximal result for the considered response as seen with a design in which the quantitative results of the method were found to be rugged. 

System suitability should be based on criteria and parameters collected as a group that will be able to define the performance of the system. Some of the common parameters used include precision of repetitive injections (usually five or six), resolution (R), tailing factor (T), number of theoretical plates (N), and capacity factor ( ). 

The resolution factor is considered to be a more discriminating measure of system suitability than column efficiency [44]. Yet, column efficiency determinations are required for the assay of antibiotics and antibiotic-containing drugs [53]. The reduced plate height (hr) for the column is determined by first calculating the number of theoretical plates per column ... 

Prior to performing a formal validation, the analytical chemist should have performed some prevalidation during method development. The expectation is that a well-developed HPLC method should subsequently be validated with no major surprises or failures. Prior to validation, specificity and some degree of robustness should be demonstrated. In addition, some form of system suitability criteria will have been established. System suitability evaluates the capability of an HPLC system to perform a specific procedure on a given day. It is a quality check to ensure that the system functions as expected and that the generated data will be reliable. Only if the system passes this test should the analyst proceed to perform the specific analysis. System suitability can be based on resolution of two specified components, relative standard deviation, tailing factor, limit of quantitation or detection, expected retention times, number of theoretical plates, or a reference check. 

Additional System Suitability Parameters. Other parameters for system suitability testing can be considered (e.g., capacity factor, number of theoretical plates, etc.). 

The separation factors for the Cg aromatics are composition dependent and may be profoundly altered by the addition of other components to the system. It is therefore essential to consider the performance of adsorbent-desorbent combinations rather than the performance of individual adsorbents and desorbents. What is required is a suitable combination of adsorbent and desorbent which, within the appropriate concentration range, gives an adequate separation factor between the components which are to be separated and for which the ancillary separations of extract and raffinate products from the desorbent are easily accomplished. The total number of theoretical plates required for the separation process is minimized when the desorbent is... 

Additional system suitability parameters Other parameters for system suitability testing can be considered (e.g., capacity factor, number of theoretical plates, etc.). Capacity factor can be especially important in methods used for stability testing, where adequate resolution of the peak of interest from the solvent front is required so that any degradation products are suitably resolved. 

Isothermal operation is not necessarily suitable for all simulated moving bed systems. The concentration of extract and raffinate streams can never exceed the concentration of feed components for a system with a linear isotherm. Furthermore, when the operating and equilibrium lines are close an excessive number of theoretical plates (to use the parlance of distillation and absorption technology) or height of each bed would be required for separation. Constraints such as these may be circumvented by non- isothermal operation of a simulated moving bed (Ching and Ruthven 1986). By maintaining bed section 1 at an elevated temperature with sections 2,3 and 4 at a lower temperature. 

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