Chapter 5Quality Assurance and Calibration Methods

Analytical Method Validation Terms

Specificity: ability of a method to differentiate between analyte andeverything else (i.e., limit interferences)

Linearity: how well a calibration curve fits a straight line Y = mX + Boften measured by R2 (R is the correlation coefficient fromleast squares data fit, closer to 1 is better fit)

Accuracy: how close measurement is to true value

Precision: how reproducible measurement is (not how accurate!)

Range: concentration interval for which all of the above are acceptable

Robustness of an Analysis Method: ability of a method to tolerateminor changes to the operating parameters (say digestion time ofsample is increased because you didn’t keep track of the time)

Limits for Analytical MeasurementsDetection Limit: smallest quantity of analytethat can be distinguished from the blank

Reporting limit: 5-10 times detection limitconcentration below which regulatoryrules report an analyte as not detected

Note: means 90% of the time weget a reliable measurement

Individually spiked samples are needed if the analysis consumes any of the sample.

Individually spiked samples are needed if the analysis consumes any of the sample.

Can only use if no sample is consumed by analysis