The Development Of A Novel Passive Sampler

A novel, simple, inexpensive and convenient passive sampler was developed. The sampler based on PTFE membrane enclosed a fixed volume of absorbing reagent. The analyte gas samples diffused through PTFE membrane and reacted with reagent. The sampler due to large ratio of sampling surface area/sampling solution volume was of high sampling rate with 15min sampling time. For the nitrogen dioxide (NO₂) determination, the absorbing reagent was prepared by sulfanilamide, tartaric acid, EDTA and N-(1-naphthyl)- ethylenediamine dihydrochloride. Ambient NO₂ diffused through the membrane and subsequently reacted with an absorbing reagent solution. The rose red was developed and the degree of colour was recorded by spectrophotometer. The absorbance value of this reagent was proportional to the NO₂ concentration in ambient air. Three different exposure surface area of samplers were compared. The larger the surface area was, the faster the sampling rate was and the higher the sensitivity was. The standard deviation of passive sampler was 10.3%, while 15.7% for standard active method. It had been successfully applied to determine the NO₂ concentrations on Kehua road in Chengdu city and sites far from the roadside. The results showed that NO₂ content on roadside was obvious higher than that of far from the roadside. Good agreements were observed between the active method and passive method. The proposed samplers were also used to sample formaldehyde in ambient air. Solution containing 2, 4-pentanedione, ammonium acetate, acetic acid was enclosed in the sampler and it was used to collect and reacted with airborne formaldehyde. The colour degree of yellow reaction product was recoded by the spectrophotometer. The results are also satisfactory.The first appended documents described the syntheses of phthalocyanines with phthalonitrile. The experiments of phthalocyanines response to oxygen and nitrite ion were done. The elementary results were got and the further work would to be processing. The second appended documents described that a home-made synchronous detector fabricated with a purple-blue light LED, two photo-resistors and sample holder in a dark box, was also used for formaldehyde determination. The yellow derivative of formaldehyde and 2,4-pentanedione had maximal absorption at 412 nm, which emission fluorescence at 508nm when excited at 425nm. Purple-blue light emission dioxide (LED) as light source, The absorption measurement was...