Method Validation, standards, Blanks, specificity, LOD, LOQ
Quality Assurance
An overall
management plan to
guarantee the
integrity of data
(The “system”)
Quality Control
A series of
analytical
measurements used
to assess the
quality of the
analytical data
(The “tools”)
Specificity
It is the ability of instrument to assess the analyte in the presence of different components which may be expected to be present in the form excipient, impurities, and other degradative products.
Range
It is defined as the intervals between upper and lower concentration of analyte present in the sample.
it is used to demonstrate that the result can be obtained in specific limits.
10-50 mg/mL
Accuracy
It is the nearness of the measured value to the true value.
It provides the indication of systematic error if obtained in any method.
Intrinsic accuracy (It shows error in the sample preparation)
Overall Accuracy ( it shows error in calculation)
Accuracy is generally expressed as
C1/C2 X 100
C1 Concentration of sample observed
C2 Theoretical True concentration of sample
Precision
It consists of intermediate precision, repeatability precision and reproducibility precision
It shows agreement between series of measurements obtain from multiple sampling of the same homogenous sample.
Intermediate precision
It is the results obtained which is in the lab variation by different analysts/different equipments/ different days.
Repeatability precision is under same operating conditions at short intervals of time.
Reproducibility precision is between different labs of different companies.
It is given by relative standard deviation
%RSD = standard deviation / mean x 100
It should be less than 1%
LOD
It is the lowest limit of the analyte that can be detected but can not be quantified in the sample.
It is given as percentage or in ppm
LOD = 3.3 x SD/Slop
SD standard deviation
Slop from calibration curve
LOQ
It is the lowest limit of the analyte that can be detected but can be quantified in the sample.
It is the ratio of 1:10
LOQ = 10 x SD/Slop
SD standard deviation
Slop from calibration curve
Robustness
It is the ability of analytical procedure to remain unaffected by the small but delibrate variations in the parameters like pH, temperature, instrument and composition of solution.