Analytical method for multi-component aqueous solutions and apparatus

Abstract

An analytical method capable of easily, rapidly, and accurately determining concentrations of a multi-component aqueous solution. Near-infrared spectra of a standard solution containing k components of known concentrations are measured n times within a range of 1,500 to 1,850 nm. A loading matrix of p columns by m rows and an intermediate matrix of k columns by m rows for an appointed factor number m are obtained from a response matrix of p columns by n rows consisting of p absorbance values of the respective spectra in a calibration stage and p absorbance values of a near-infrared spectrum within a wavelength range of 1,500 to 1,850 nm of a test liquid. The test liquid contains k components including pure water of unknown concentrations. The concentrations of the k components are determined from a group of absorbance values and the loading and intermediate matrices obtained in the calibration stage by a matrix operation in an prediction stage. In the calibration stage, k+1 characteristic contents can be obtained by adding a solution temperature as one of characteristic items, and k concentration values and one temperature value can be obtained in the prediction stage.