Mari Katsumine

Routine check of baseline noise in ion chromatography

The long-term check of baselines in an ion chromatograph for more than two years reveals that the suppressor breakdown and solvent contamination can be detected by the anomalous patterns of the power spectra of the baseline noise. The signal is not referred to in this study. The early detection of the troubles is possible and the quality of a new suppressor can also be examined by the noise pattern. Coupled with the signal information such as shape and elution time, the above methodology will provide a rapid and reliable routine check for ion chromatography.

Statistical and probabilistic approaches to confidence intervals of linear calibration in liquid chromatography.

The aim of this paper is to compare the reliability of two approaches to estimate the 95% confidence intervals of linear calibration in real situations. One is the statistical approach, which is well known in statistics, and the other is the probabilistic approach, which is based on a theory to predict the precision of instrumental analyses mainly from signal and noise, called FUMI (Function of Mutual Information) theory. The high-performance liquid chromatographic determination of quisalofop and maltose is taken as an example. Calibration lines obtained under the same experimental conditions are superimposed on the 95% confidence intervals to investigate whether the resulting confidence intervals can include all the calibration lines reasonably. A pair of 95% confidence intervals (upper and lower limits) can be calculated from each calibration line, but varies from calibration line to calibration line, although obtained under the same experimental conditions. The variability and reliability of the 95% intervals are also examined.