Indirect method for flame-photometric determination of molybdate and tungstate in technological solutions

A method for determining Mo and W in process solutions is described. It is based on reduction in the intensity of radiation of Rb and Cs in the flame of the lighting gas-air mixture in the presence of the test elements. The degree of quenching the radiation of alkaline elements depends on the concentration of molybdate and tungstate in solution and increases in the series Na-Li-K-Rb-Cs, and also from molybdate to tungstate. The radiation of rubidium and cesium has been detected from the resonance lines of 780.0 nm and 852.1 nm. Molybdate and tungstate standard solutions have been prepared by dissolving and exact batch of trioxide in ammonia, and solutions of rubidium and cesium chlorides, by dissolving an exact batch of the salts in water. The calibration plots are constructed in coordinates [DELTA 1:log C], the relative standard deviation being 0.9 - 0.12. The determination of molybdate and tungstate is affected only by those solution components whose presence changes the value of the analytical signal of radiation of Rb and Cs. This effect is insignificant for process solutions in which the main component is molybdate or tungstate, and the interfering ions (Al, Fe, Ni, Ca, Mg, Na, and K) are present as impurities (< 1.0 g/l)