Analytical Instrument Documents

Application note ER260003

ESR Measurement sensitivity correction

Quantitative ESR measurements aim to determine the concentration and number of unpaired spins in a sample, providing valuable insights into radical concentrations and defect densities across various fields such as physics, chemistry, biology, geology, and materials science. ESR signal intensity depends on multiple factors, including sample properties, cavity Q-value, microwave field distribution and sample positioning, sample volume, and measurement conditions such as temperature.

To achieve accurate quantitative comparisons between samples, these factors must be properly accounted for to avoid artifacts caused by measurement conditions. Sensitivity correction typically involves calibration using a standard sample with a known spin concentration, normalization with a Mn marker, normalization by sample mass, volume, or amount, and temperature correction based on the Boltzmann distribution.