Grades nitrogen dioxide

Nitrogen dioxide in air and nitrate and/or nitrite in water, soil, analytical-grade KBr, potassium sulfate, ammonium sulfate, potassium nitrate and ammonium nitrate and toothpaste were determined by means of the decrease in absorbance of Neutral Red caused by diazotization with nitrite from the sample [4]. A mixture of oxalic acid, p-aminoacetophenone and Al-1-naphthyl ethylenediamine has been proposed as an efficient absorbing system for in situ spectrophotometric determination of nitrogen dioxide in environmental samples [5]. 

Supercritical fluid grade carbon dioxide (Scott Specialty Gases, Plums teadvi lie, PA) was used as the carrier fluid. A Lee Scientific Model 501 supercritical fluid chromatograph equipped with a flame ionization detector (FID) and a nitrogen-phosphorus detector (NPD) was the instrument utilized for these studies. Fused silica capillary columns (50 pm i.d.) were employed for all the experiments. Three column types with stationary phases of three different polarities were used SB-Methyl-100, SB-Biphenyl-30 and Carbowax 20M (0.25 pm films). Frit restrictors were used to maintain pressure and proper flow rates in the column. The restrictor was connected to the end of the column via a zero dead-volume union. The end of the restrictor was positioned in the detector at 1 mm below the end of the flame jet. The detector was operated at 325-350 C with nitrogen make-up gas at 25 mL/min. Split injection was used in these experiments with 0.2 pL injection rotor and a split ratio of approximately 10 1. 

Surface area by nitrogen absorption method Total gas in reactor-grade uranium dioxide pellets Thorium and rare earth elements by spectroscopy Hydrogen by inert gas fusion... 

Nitrogen dioxide is available in grades of 99.5 percent or 99.995 percent. 

Semiconductors. Phosphine is commonly used in the electronics industry as an -type dopant for siUcon semiconductors (6), and to a lesser extent for the preparation of gaUium—indium—phosphide devices (7). For these end uses, high purity, electronic-grade phosphine is required normally >99.999% pure. The main impurities that occur in phosphine manufactured by the acid process are nitrogen [7727-37-9] hydrogen [1333-74-0] arsine [7784-42-17, carbon dioxide [124-38-9], oxygen [7782-44-7], methane [74-82-8], carbon monoxide [630-08-0], and water [7732-42-1]. Phosphine is purified by distillation under pressure to reduce the level of these compounds to <1 ppm by volume. The final product is sold as CYPURE (Cytec Canada Inc.) phosphine. 

Fluidized bed combustion boilers are often conventional boilers but with unconventional, specially designed furnace beds. Fluidized bed combustion boilers are used to burn solid fuels, such as low-grade, high-sulfur crushed coal. The benefit of this process is its ability to provide 95 to 100% combustion (depending on the reactivity of the fuel) combined with reduced emissions of sulfur dioxide (S02) and nitrogen oxides (NOx). 

Experiments were made in a nitrogen atmosphere using reagent grade chemicals and triply distilled carbon dioxide-free water. Standard solutions of... 

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