| 摘要 |
The present invention relates to a method of spectrophotometric analysis designed for determining the concentration of substance in solution by absorption of ultraviolet radiation. The proposed method consists in alternately, in orderly sequence, filling a reference cuvette and a measuring cuvette with reference solutions with known concentrations C1 and C2 of the substance and the analyzed solution with unknown concentration CX of the substance, passing, exposing the cuvettes to monochromatic ultraviolet radiation with a specified intensity and a wavelength, dividing the radiation flux that passed through the cuvettes into two components with equal intensities, modulating each flux component by interruption, converting the intensities of the modulated radiation flux components into electrical signals by a photodetectors, isolating and amplifying the alternating components of the output signals of the photodetectors, performing the synchronous detection of the said alternating components, measuring and storing the output direct voltages of the corresponding synchronous detectors, and determining the concentration of the substance by the following equation: or , where CX is unknown concentration of the substance in the analyzed solution; C1 and C2 are the known concentrations of the substance in the reference solutions; U1, U2, U3, and U4 are the output direct voltages obtained on the synchronous detection of alternating components of the output signals of the photodetectors; n2 = 2 is the constant of proportionality. The present invention provides a possibility to increase accuracy and extend measurement range in determining concentration of substances.
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