99.9% blue tungsten oxide nanopowder’s quality is guaranteed by determining ammonia content to meet clients’ requirements. Therefore, people studied the determination method of ammonia in blue tungsten oxide. It has been proved by experiments and practice that the following methods may meet production control to analyze ammonia indicators in blue tungsten oxide.
1. Instruments and Reagents
Four conical flasks (300ml) with double- hole rubber plugs. A flow meter cylinder. C(1/2H2SO4)=0.5mol/L H2SO4 standard solution; C(Noah)=0.5mol/L NaOH standard solution. 30% NaOH solution. 0.2% methyl red ethanol solution.
2. Experimental Procedures
Step one: Weigh 1g (with an accuracy of perhaps 0.0002g) sample and add it in a 300ml conical flask, then pour about 100ml of water, and then add 30% NaOH solution 20ml. Pour 10ml of H2SO4 standard solution of C(1/2H2SO4)=0.5mol/L in another flask, and pour water to 100ml, and then add two drops of 0.2% methyl red ethanol solution.
Step two: Connect the conical flasks, as shown in above picture (1 and 3 is sample+30% NaOH solution; 2 and 4 is H2SO4 standard solution). And turn on the flow meter cylinder, then control the gas flow rate at 1000ml/min, heat the conical flasks containing sample in water bath, and remove the absorption conical flask after 1 hour of ventilation. Then, use NaOH standard solution of C(NaOH)=0.5 mol/L to titrate the excess sulfuric acid standard solution.
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