Apparatus for the determination of a concentration of a component to be measured in a gas

An apparatus for the determination of a concentration of a component to be measured in a gas, comprising:

• a light source (12);
• a measurement cuvette (28) including an input opening and outlet opening, positioned to receive light from the light source;
• an absorption apparatus having an inlet and an outlet, positioned in fluid communication with the measurement cuvette via the outlet opening of the measurement cuvette;
• a reference cuvette (40) having an input opening and an outlet opening, arranged in the optical beam path in parallel to the measurement cuvette the outlet of the absorption apparatus in fluid communication with the input end of the reference cuvette;
• at least one light receiver (32, 44);
• and an evaluation unit (34) which determines the concentration from the signals of the light receiver (32, 44),
• wherein the gas to be analyzed is supplied to the measurement cuvette (28), on the one hand, and, on the other hand, via an absorption apparatus (50) which includes a substance which completely absorbs the component to be measured to the reference cuvette (40),
• wherein the component to be measured is H2S and wherein a wavelength selection unit (13) is provided for the selection of an absorption wavelength (λAbs), and
• wherein the gas to be analyzed is supplied in parallel to the measurement cuvette (38) arranged to receive gas and discharge gas into the absorption apparatus, on the one hand, and, on the other hand, via the absorption apparatus (50) arranged to receive and discharge gas into the reference cuvette (40), wherein a current matching apparatus (51) is arranged in the supply for the measurement cuvette (28) which, from a construction point of view, is of identical design to the first absorption apparatus (50), but does not include any substance absorbing the component to be measured.