Operative conditions of automatic recording analyzer for oxygen using optical integration method

Abstract

For refining the operative conditions in connection with the automatic recording analyzer for organic oxygen, in that the Unterzaucher's principle has been combined with a new technique of optical integration along the vapor phase iodine introduced in a long gas cell kept at 120°C, further investigations have been carried out on the following items.
Maximum absorbance of the vapor phase iodine was observed at the fixed wavelength of 525 mμ during a change of temperature between 100180°C, while the transmittance at the same wavelength changed with a rate of 0.04%/°C at around 70% transmittance.The flow rate of carrier gas was allowed within a range of 1070 ml/min, but 2050 ml/min was suggested for the normal operation. With the gaschromatographic observations, sulfur-containing fractions produced in the thermal decomposition tube were perfectly trapped by a net of reduced copper instead of by metallic silver. No hydrocarbon was detected from various organic samples, except for methane which did not react with iodine pentoxide. The cause of the blank value was therefore attributed to some oxygen-containing impurities and/or water adsorbed on samples. The reproducibility of calibration line was highest when the different standard samples were taken in approximately the same weight, e.g. 1.51.7 mg. The weight of unknown samples in routine analysis should be also limited within this regular blank range.