Reagent solutions and gases

2 REAGENT SOLUTIONS AND GASES The reagents are listed alphabetically. One asterisk indicates that a reagent has a limited stability and should not be kept for longer than 1 month. Two asterisks indicate that the reagent should be prepared freshly and discarded after use. Reagents with no asterisk can be kept for at least one year after preparation. 

Albumin solution. Dissolve 0-1 g albumin in 20 ml water to obtain a colloid solution. 

Acetic acid (1 1 or 9m). To 50 ml water add 50 ml glacial acetic acid and mix. 

Acetic acid (30 % v/v). Dilute 30 ml glacial acetic acid, CH3COOH, with water to 100 ml. 

Acetic acid (2m). Dilute 114 ml glacial acetic acid with water to 1 litre. 

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The analytic principles that have been applied to accumulate air quality data are colorimetry, amperometry, chemiluminescence, and ultraviolet absorption. Calorimetric and amperometric continuous analyzers that use wet chemical techniques (reagent solutions) have been in use as ambient-air monitors for many years. Chemiluminescent analyzers, which measure the amount of chemiluminescence produced when ozone reacts with a gas or solid, were developed to provide a specific and sensitive analysis for ozone and have also been field-tested. Ultraviolet-absorption analyzers are based on a physical detection principle, the absorption of ultraviolet radiation by a substance. They do not use chemical reagents, gases, or solids in their operation and have only recently been field-tested. Ultraviolet-absorption analyzers are ideal as transfer standards, but, as discussed earlier, they have limitations as air monitors, because aerosols, mercury vapor, and some hydrocarbons could, interfere with the accuracy of ozone measurements made in polluted air. 

In the last-named case the reaction is dangerously explosive and should only be carried out with small quantities of the reagents. Ozone is also formed during the decomposition by heat of potassium chlorate, and by the action of nitric acid, preferably of density 1-33, on ammonium persulphate1 carefully warmed up to 65° to 75° C. The liberated gases are washed with caustic-potash solution and contain from 3 to 5 per cent, of ozone. 

The presence of dissolved gases in the involved solutions, which may be released during the coalescence of solution due to their solubility. This aspect becomes more severe in concentrated solutions and water-miscible organic solvents and/or when the system is operated under negative pressure (see also 5.4). The process used to obtain distilled-deionised water in the laboratory for reagent preparation can also have an effect ... 

In this context, attention should be drawn to those procedures where formation of gases might take place in the FIA system itself. This will happen whenever the partial pressure of the gas exceeds that corresponding to the solubility of the gas under the prevailing conditions, thus leading to formation of microbubbles. Thus without protection from the ambient air, alkaline reagent solutions will absorb carbon dioxide, and if the re-... 

The distillation method of moisture determination requires the collection and determination of the water evolved from the coal when the sample is heated in a boiling solvent which is itself immiscible with water. The solution and extraction methods require either solvent extraction of the water from the coal (followed by subsequent determination of the water content of the solvent) or use of a standard reagent which will exhibit differences in concentration by virtue of the water in the coal. The chemical methods of water determination invoke the concepts of direct chemical titration of the water or chemical reaction between the water and specific reagents which causes the evolution of gases and the water is determined by measurement of the volume produced. Finally, the electrical method requires the measurement of the dielectric constant of the coal from which the water content can be determined. 

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