Determination of phosphorus pentoxide in ambient air by molybdenum blue ascorbiaccid to deoxidize spectrophotometric method

Determination of phosphorus pentoxide in ambient air by molybdenum blue ascorbiaccid to deoxidize spectrophotometric method has been established. In order to acquire the optimal conditions,various parameters were studied,such as wavelength,cuvette specifications,different acidities of reaction system,the amount of the reagent ammonium molybdate,ascorbic acid and potassium antimony tartrate,color temperature and time. At the same time, three different filters vinyl chloridefilter, glass fiber filter and quartz filter were compared respectively,and it was found that vinyl chloride filter has low background. Results show that this method has a good performance,a wide range of the standard curve,the linear correlation coefficient of 0. 9999,the detection limit and low determination limit are 0. 15 and 0. 60 μg / m3,respectively when the sampling volume is 5 m3; In addition the recoveries of different concentrations in blank quartz filters and actual samples are in the range of97%- 110%,precision is less than 10%. Combined with practical work, effects of arsenic, mercury,chromium,silicon and fluoride on the method were studied. When the arsenic content is more than 0. 2 μg / m3 and chromium( VI) content is more than 200 μg / m3,negative interference on this method is found,the mixed solution of sodium sulfite and sodium thiosulfate could eliminate the interference. The interference of silicon can be eliminated by first preparation of the mixed reductants and then added,and mercury and fluoride does not generate interference on this method.