Abstract: A method and apparatus for determining, by use of ion chromatography, a microconstituent contained in a major constituent as impurities present in the major constituent. The invention causes only that portion of the effluent from the detector, shown on an ion chromatograph, that corresponds to the neighborhood of the microconstituent to be led again to the collecting valve. Thus, the microconstituent of the solution can be determined quickly and easily, without reference to the kind of microconstituent being tested.

Abstract: A method and apparatus for determining, by use of ion chromatography, a microconstituent contained in a major constituent as impurities present in the major constituent. The invention causes only that portion of the effluent from the detector, shown on an ion chromatograph, that corresponds to the neighborhood of the microconstituent to be led again to the collecting valve. Thus, the microconstituent of the solution can be determined quickly and easily, without reference to the kind of microconstituent being tested.

Abstract: Method and apparatus for analysis, by ion chromatography, of anions, in a sample solution, wherein accurate analysis of anions in the sample solution is obtained by passing carbonic acid, through a prescribed membrane, into the sample solution, thereby completely eliminating or sharply lessening the so-called water dip effect. The method and apparatus are further directed to enabling anions in the sample solution to be accurately analyzed by passing prescribed cations, through a prescribed membrane, into the sample solution, thereby depriving the sample solution of interfering anions otherwise abundantly present therein.

Abstract: Method and apparatus for analysis, by ion chromatography, of anions, in a sample solution, wherein accurate analysis of anions in the sample solution is obtained by passing carbonic acid, through a prescribed membrane, into the sample solution, thereby completely eliminating or sharply lessening the so-called water dip effect. The method and apparatus are further directed to enabling anions in the sample solution to be accurately analyzed by passing prescribed cations, through a prescribed membrane, into the sample solution, thereby depriving the sample solution of interfering anions otherwise abundantly present therein.

Abstract: A metallic block has a conical measuring-light inlet port and a conical reference-light inlet port formed therein. The ports intersect at a light sensor. The inlet ports are closed by respective multilayer interference filters. Temperature control means, which may be responsive to the light sensor output, maintains the metallic block, and thus the filters and sensor, at a fixed temperature.

Abstract: To detect the density of a measurement component of a sample gas, infrared light is directed alternately through a measuring-light optical system and a reference-light optical system to a heated light sensor. The measuring-light optical system includes a sample cell, a first filter for transmitting infrared rays of a fixed wave-length band, and a temperature compensating cell having a gas which has a part of its absorption wave-length band within the transmission wave-length band of the first filter but has a spectrum different from the spectrum of the measurement component. The reference-light optical system includes a light throttle, an interference cell having a gas containing a fixed density of the measurement component, an adjustable-length interference compensating cell filled with the sample gas, and a second filter for transmitting rays of a wave-length band that includes the major part of the transmission wave-length band of the first filter.