Specificity in analytical method validation – type of interference

Specificity

As per ICH Q2A guideline defined as
Specificity is the ability to assess  unequivocally analyte in the present of component which may expected to present. Typically these might include impuries, degradants, matrix etc

Selectivity

The extent to which the method can be used to determine particular analytes in mixture or matrices without interference form other components of similar behavior

Majorly term of use International pure and apply chemistry mostly term used

• Selectivity
• Specificity
• Analytical Specificity
• Diagnosis Specificity

What is effect of interference ?

the concertation of analyte is normally not measured directly.  Instead a specific property (e.g intensity of light) is quantified.

It is, therefore, crucial to establish that the measured property is only due to the analyte and not to something chemically or physically similar, or arising as a coincidence thus causing a bias in the measurement result.

So to perform selectivity to evaluate to ability of a method to the target in presence of other components expected to present in sample

Different type of interference effect ?

• Proportional effect or Rotational effect
• Translational or fixed effect

– Proportional effect or Rotational effect

• Increasing or decreasing single with concentration.
• Effect propositional to signal.
• Changes the calibration slope
• Does not impact intercept

– Translational or fixed effect

• Independent of the concentration
• Due to as “background” or Baseline
• Does not changes the calibration slope
• Affect the intercept