在空气二氧化氮的比色测定中影响转换系数的因素探讨

作者探讨了在 NO_2 比色测定中,NO_2 浓度、吸收液组成及采样流速对NO_2 转换系数的影响。结果表明,使用液体吸收法时,NO_2 转换系数随 NO_2浓度降低而增加,当NO_2 浓度小于 1 mg/m~3时,其增加更为显著。而使用TEA 浸渍滤纸吸收法时,在0.2～4.6mg/m~3 范围内,NO_2转换系数(k)与NO_2浓度(C)的关系可表示为k=0.026C+0.725。不同组成的吸收液转换系数不同;流速的增加使转换系数下降。

STUDY OF FACTORS INFLUENCING THE SALTZMAN FACTOR IN SPECTROPHOTOMETRIC DETERMINATION OF NO_2 IN AIR

The Saltzman factor (conversion coef-ficient)in the determination of NO_2 in air isinfluenced by many factors. The authorshave studied how such factors as the con-centration of NO_2 the composition of thetrapping solution, the relative contents inthe solution, and the flow rate influencethe Saltzman factor. The results showedthat when the Saltzman-type trapping so-lution was used,the Saltzman factor in-creased when the concentration of NO_2 de-creased,and when the concentration of NO_2decreased from 1 mg/m~3, the Saltzman fac-tor increased very sharply. But when NO_2was absorbed on the TEA-impregnated fil-ter paper and was determined with the mo-dified Saltzman reagent, the relationship ofthe Salzman factor (k) and concentrationof NO_2(C) to the extent of 0.2-4.6 mg/m~3could be,expressed in the equation: k=0.026 C + 0.725. The composition and therelative contents in a trapping solution hadstrong influences upon the Saltzman factor.The changes in the composition or in therelative contents would lead to the changesin the Saltzman factor. The experimentaldata showed that sulfanilamide in place ofsulfanilic acid couldn't raise the Saltzman factor. This is contrary to the conclu iondrawn by C. Huygen, et al. In spite of thefact that the increase of the flow rate leadsto the decrease of the Saltzman factor, theeffect is not very obvious.