Prediction of Measurement Precision by Chemometric Invalidation of Flow Pulsation in Refractive Index Detection of Liquid Chromatography.

Abstract

The standard deviation and relative standard deviation of measurements in the refractive index detection of liquid chro-matography are predicted based on the 1/f fluctuation model which is made up of white noise and the Markov process. First, repeated measurements and Monte Carlo simulation corroborate the reliability of this prediction in the absence of flow pulsation. Pulsation, if any, can be distinguished in the frequency space from the 1/f noise which is common to most analytical instruments. In this case, the uncertainty prediction is also available without modifying the prediction theory, if a zero window is set at the time period of a fundamental tone of the pulsation (virtual invalidation of pulsation). The zero window is used for determining the zero level relative to which the signal intensities are summed for a signal area (measurement). A maltose determination is taken as an example.