215 



The Determination op Hydrogen, Nitrogen and Methane in 

 Gas by Combustion in a Quartz Tube. 



By Frank C. Mathers and Ipa E. Lee. 



The purpose of this research was to devise a more convenient and. a 

 more accurate method for the determination of liydrogen, nitrogen and 

 methane in gas. Many different methods^ have been advocated for making 

 this analysis. The Drehschmidt method- of burning tlie gas residue mixed 

 with oxygen, liy pas.«ing it thi-ougla a hot platinum capillary tube is perhaps 

 tlie best scheme. However, the high cost of the platinum capillary tube 

 together with the rapid deterioration of the apparatus makes a modifica- 

 tion desirable. The experiments described in this i)aper show that a quartz 

 lube filled with pieces of scrap platinum is an entirely satisfactory substi- 

 tute for the platinum capillary tube in the Drehschmidt apparatus. 



The quartz tube was 30.5 cm. long, 7.25 mm. outside and 3.38 nun. 

 inside diameter. Its volume, determined by the weight of mercury required 

 to fill it, was 3.317 cc. The platinum scrap which was used as a contact 

 substance in the quartz tube was prepared by cutting pieces of ordi- 

 nary scrap platinum wire, which every laboratory has in quantity, into 

 as short pieces as possible with a shears. These small fragments were 

 then placed upon stiff paper which was passed through a cornet roll mill 

 a number of times. These flattened pieces of platinum presented a large 

 surface to the passing gas and at the same time offered very little resist- 

 ance to the passage of the gas. Two pieces of scrap platinum gauze were 

 used, one in each end of the quartz tube, to keep the small pieces of plati- 

 num in position. The platinum weighed ll.lSD grams and had a volume 

 of 0.522 cc. The platinum occupied 21.6 cm. of the length of the tube. 



The data concerning the many preliminary experiments which merely 

 served to detect the errors, will be omitted. The following form of appa- 

 ratus and manipulation were found to be satisfactory. 



A mercury pipet holding the gas to be burned and the oxygen required 

 for the combustion, was connected to one end of the quartz tube by a 



^"Review of progress in sas analysis," Chomiker Zeitung, 33:801 and 817 (1908). 

 • Hempel-Dennis, "Gas Analysis," p. 140. 



