Tailing factor

An algorithm for calculating the symmetrical (two-tailed) /-factors for p = 0.1 is incorporated its use corresponds to the statement that the probability that measurements on a future batch, given the linear trend already established, will inadvertently be found to be below the specification limits of Y% of nominal, at a shelf-life that would lead one to expect a residual content at or above the specification limit, is p = 0.05. ... 

Chromatographic system (See Chromatography <621 >.) The liquid chromatograph is equipped with a 230 nm detector and a 4.6 mm x 30 cm column that contains packing L7. The flow rate is about 2 mL/min. Chromatograph the Resolution solution and the Standard preparation, and record the peak responses as directed under Procedure the resolution, R, between the dibutyl phthalate and miconazole peaks is not less than 5, the tailing factor for the miconazole peak is not more than 1.3, and the relative standard deviation for replicate injections of the Standard preparation is not more than 2%. The relative retention times are about 0.7 for dibutyl phthalate and 1 for miconazole. 

Determining peak-asymmetry and peak-tailing factors. Peak asymmetry = B/A, and peak tailing factor = (A + B)/2A. 

Asymmetry <3.5 (T = W5%/2f), where T is the tailing factor, W5% is peak width at 5% peak height, and f is the width at 5% peak height measured from the leading edge to a vertical line extrapolated from the apex of the peak. 

Table 1 gives the tailing factor for the basic analyte amitriptyline at neutral pH on several commercially available packings. One can clearly see the difference between the older packings and the newer packings based on high-purity silicas. It is unquestionable today that surface silanols on a packing participate in the retention of basic analytes, and... 

A tentative list of factors that may be investigated in the robustness test is presented in Table 8. This list is not complete and additional factors may be added. The limits for the factor levels are proposals and should be evaluated case by case. The significance of the effects of the factors on the responses such as the resolution of all peak pairs, the tailing factor, retention times, analysis time, etc., is evaluated. 

Peak area reproducibility Capacity factor k ) Tailing factor Resolution (Rg) Theoretical plates (N) % RSD of replicate injections k large enough to provide adequate retention Tf=l demonstrates no tailing, acceptable range shown Minimum resolution required for critical pair Minimum theoretical plates allowed for separation... 

Other than selecting the column and mobile phase for the correct mode of separation, optimizing different HPLC parameters (injection volume, run time, wavelength, and detector) is equally important for achieving acceptable capacity factor (k ), resolution ( R), and tailing factor (T). 

Several method performance indicators are tracked, monitored, and recorded, including the date of analysis, identification of equipment, identification of the analyst, number and type of samples analyzed, the system precision, the critical resolution or tailing factor, the recovery at the reporting threshold level, the recovery of a second reference weighing, the recovery for the control references (repeated reference injections for evaluation of system drift), the separation quality, blank issues, out of spec issues, carry over issues, and other nonconformances. The quantitative indicators are additionally visualized by plotting on control charts (Figure 23). 

Studied responses were resolution, " " analysis time, migration time, plate count, tailing factor, tablet content, peak area, peak height, peak width, and peak area/migration time ratio. ... 

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 ( ). 

Acceptance criteria for tailing factor, percent injection reproducibility, relative standard deviation of calibration and/or control standard... 

Assessment of USP tailing factor using predefined acceptance criterion... 

Chromatograph the Standard preparation, and record the peak responses as directed for Procedure the column efficiency is not less than 20,000 theoretical plates the tailing factor is not less than 0.8 and not more than 2 and the RSD for replicate injections is not more than 2%. 

For the analysis of semivolatile organics, a column performance test for base/neutral and acid fractions must be performed to test the efficiency of chromatographic column for separation of the analytes. For the base/neutral fraction, inject 100 ng of benzidine and determine the benzidine tailing factor which must be less than three. Similarly, for acid fraction, inject 50 ng of pentachlorophenol and calculate its tailing factor which must be less than five. 

The calculation of tailing factor is shown below in Figure 1.4.2. Both benzidine and pentachlorophenol may be added onto the DFTPP standard and injected. If the column performance test fails, replace the column packing to achieve the tailing factor criteria. 

The point at which a column used for HPLC will fail depends largely upon how the operator uses it. Eventually, however, all HPLC columns will fail. The onset of column failure can be monitored by two common failure parameters the peak asymmetry factor, As, and the peak tailing factor. These parameters are defined according to the figure below ... 

Peak Asymmetry Factor (As, 10%) Peak Tailing Factor (5%)... 

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)... 

It should be noted that the tests and specifications listed in Table 7 are provided for guidance and should be set for each individual method based on its application and performance. For example, there may be no resolution requirement for an HPLC dissolution assay. For the same method, it may also be impractical to set the injector repeatability requirement at an RSD of < 1% if the peak response for the API is very small. Again, in the same example it is also impractical to require a check standard to be within 1% of the working standard if the RSD requirement for replicate analyses of the working standard is <2 %. Some ion exchange columns may not provide plate counts of > 2000 or tailing factors of < 2. 

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