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Validation in a Chemical Analysis. - Coggle Diagram
Validation in a Chemical Analysis.
Quantitative
accuracy and precision( repeatability and reproducibility)
working range or target level as guidance for a curve
coefficient of determination,R2 equal to or better than documented in the method
-Single analyte / single matrix methods R2 ≥0.995
-Multi residue, multi class mass spectrometer : analysis R2
value of ≥ 0.990
Analyze reference materials, standard, or spike samples at ≥R2 concentration levels in triplicate
Method Detection Limit (MDL)/Limit of Detection (LOD) -MDL is stated in the method, result should be within ± 30% of the known value.
-If MDL not provide,LOD may be determined by analyzing sample blank,calculating the standard deviation and express as the mean plus 3 standard deviations.
LOQ(the minimum amount/concentration that can be qualified with acceptable precision)
If available, prepare and analyze a Quality Control Sample/ Certified Reference Material.
For a standard curve, analyze calibration standards containing known amount of analyte.
Calculate percent recovery. The result should be within 20% of the known value for acceptable method performance.
minimum requirement:
Precision
Meets System suitability
Limit of Detection
Accuracy
Working Range/Linearity
Limit of Quantitation
Glossary/Definition
Analytical batch
– An analytical batch consists of samples which are analyzed together with the same method sequence and the same lots of reagents and with the manipulations common to each sample within the same time period or in continuous sequential time periods
Accuracy
- Accuracy is the nearness of a result or the mean of a set of measurements to the true value.
Linearity
– The ability of the method to elicit results that are directly proportional to analyte concentration within a given range.
Method Detection Limit (MDL)
- The minimum amount or
concentration of analyte in the test sample that can be reliably distinguished from zero.
Dependent on:
1.sensitivity
instrumental
noise
blank variability
5.sample matrix variability
6.dilution factor
Non-standard method
– This refers to a method that is not taken from authoritative and validated sources.
This includes methods from scientific journals and unpublished laboratory-developed methods
Detection limit
– A detection limit is the lowest amount of analyte in a sample which can be detected but not necessarily quantitated as an exact value which is the lowest concentration level that can be determined statistically different from a blank at a specfied level of confidence.
Limit of quantitation (LOQ)
– This is the level above which quantitative results may be determined with acceptable accuracy and precision.
FDA "official" methods
compliance programs and special assignments
applications and petitions
specified by the manufacturer of the equipment
Precision
- agreement between a set of replicate
measurements without assumption of knowledge of the true value.
Range – A range is the interval between the upper and lower concentration of analyte in sample
Ruggedness or robustness
– Ruggedness is a measure of an analytical procedure’s capacity to remain unaffected by small,
Selectivity
– The extent to which a method can determine particular analyte(s) in a mixture(s) or matrix(ces) without interferences from other components
Sensitivity –
The change in instrument response which corresponds to a change in the measured quantity
Specificity
– In quantitative analysis, specificity is the ability of a method to measure analyte in the presence of components
Qualitative Chemistry Methods
Establish LOD
Detection limit (lowest level) gives positive response. Referred as MDL when applied to complete analytical method
Linearity
Meet system suitability requirement
Analyze ≥3 matrices where available