Sensitivity deviation: instrumental linearity errors that influence concentration analyses and kinetic evaluation of...

Area of Science:

• Analytical Chemistry
• Biophysics
• Instrumentation Science

Background:

• Scientific instruments often use array detectors like CCDs or photodiode arrays to track optical patterns.
• Instruments for affinity biosensing, such as surface plasmon resonance (SPR), rely on these detectors.
• Accurate tracking of pattern changes is crucial for reliable data in bioanalytical instruments.

Purpose of the Study:

• To introduce a new parameter, sensitivity deviation, to quantify linearity errors in array detector systems.
• To highlight the impact of linearity errors on the accuracy of biosensing data.
• To present a method for detecting these subtle linearity errors.

Main Methods:

• Introduction of the 'sensitivity deviation' parameter to measure deviations from the true calibration curve slope.
• Analysis of the relationship between integral linearity errors and sensitivity deviation.
• Development and outlining of a method for detecting linearity errors.

Main Results:

• Linearity errors, though small relative to the dynamic range, can cause significant sensitivity deviations (e.g., <1% linearity error leading to 10% sensitivity deviation).
• These deviations can lead to misinterpretation of kinetic data, mass transport limitations, and concentration analyses in biospecific interaction analysis (BIA).
• The phenomenon is not limited to SPR instruments and occurs in other systems using array detectors.

Conclusions:

• Linearity errors in array detectors pose a significant challenge to the accuracy of bioanalytical instruments.
• The sensitivity deviation parameter provides a critical measure for assessing data integrity.
• Accurate detection and correction of linearity errors are essential for reliable biospecific interaction analysis and other applications using array detectors.