System suitability tailing factor

System suitability tests for chromatographic impurities procedures, such as precision, resolution factor, calibration standard, and tailing factor, should be considered as appropriate. In the presence of multiple peaks, a resolution factor between the two closest peaks should be proposed. For reliable quantitation, baseline resolution of the impurities will provide accurate measurement of the... 

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 ( ). 

Chromatographic system (see Chromatography, in the general procedure (621)) The liquid chromatography is equipped with a 280-nm detector and a 4.6 mm x 15-cm column that contains 5-/im packing L7. The flow-rate is about 0.8 ml/min. Chromatograph the System suitability solution, and record the peak responses as directed for Procedure the capacity factor, k , is not less than 6 the column efficiency is not less than 3000 theoretical plates the tailing factor is not more than 1.5 and the relative standard deviation (RSD) for replicate injections is not more than 1%. 

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)... 

The suitability of the system is determined by chromatographing the Standard solution, and recording the peak responses as directed under Procedure. The tailing factor is not more than 2.0, and the relative standard deviation for replicate injections is not more than 4.0%. 

System suitability parameters with their respective acceptance criteria should be a requirement for any method. This will provide an added level of confidence that the correct mobile phase, temperature, flow rate, and column were used and will ensure the system performance (pump and detector). This usually includes (at a minimum) a requirement for injection precision, sensitivity, standard accuracy (if for an assay method), and retention time of the target analyte. Sometimes, a resolution requirement is added for a critical pair, along with criteria for efficiency and tailing factor (especially if a known impurity elutes on the tail of the target analyte). This is added to ensure that the column performance is adequate to achieve the desired separation. 

System suitability requirements for retention time, efficiency, resolution, and tailing factor are set based on prior method challenging experiments and prior method development experience. This is a dynamic process and as the user gains more experience with the method, the breadth of the acceptance criteria is further expanded until the method is finally validated for the intended purpose. 

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. 

For system suitability smdies, five replicate injections of mixed standard solutions were injected and parameters such as relative standard deviation of peak area, column efficiency, resolution, and tailing factors of the peaks were calculated. Results are shown in Table 3. 

In addition to validation of the automation, full validation of the chromatographic procedure, as described in Chapter 12, should be conducted for late-phase methods. This should include specification of system suitability parameters to ensure that the performance obtained during method development and validation is maintained during routine use. The system suitability parameters may include specification of acceptable injection repeatability, criteria for resolution between critical pairs, maximum allowable tailing factors, and a means of verifying that the requisite sensitivity is obtained. As recommended by Vander Heyden et al., system suitability limits are best set following robustness tests. 

Figure 5.12. A summary report for system suitability testing documenting result i.d., precision, and other system suitability parameters (S/N ratio, tailing factors, plate count, and resolution). Note that means and precision of each table column can be automatically calculated.

Acceptable levels of peak tailing should be indicated in the system suitability section of the method as peak asymmetry or tailing factor. Once the limits have been exceeded, a number of basic checks can be carried out that can assist in the diagnosis. A lot of problems of this nature are found to be due to analyst error, and the mobile phase composition and column choice should always be checked as a matter of course. 

Validation of a chromatographic system is required by numerous quality assurance systems. For this purpose hardware, firmware, software and the analytical method used for analysis should be validated. Moreover, the chromatographic system needs to be tested against documented performance specifications for a given analytical method (system suitability test). Besides the prerequisites of a chromatographic separation, such as tailing factor, column... 

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