Studies On Determination Of Aldehyde And Ketone In Environment And Photodegradation Of It's Precursor Compounds

Pollutants such as aldehyde and ketone, among major pollutants in atmosphere environment, are strictly limited by every nation for their discharges because of their high toxicity and numerous sources. It is the base for appraising the atmosphere environmental quality and investigation of the origins and end-results of the pollutants that exactly determining the pollutants.In the paper, the determination on the several kinds of pollutants such as representative aldehyde and ketone was systematically investigated. At the same time, the sampling and analysis methods suitable for environmental determination were chosen and the emphasis was made on the influences of experimental conditions on determination results. Concretely, the well-chosen determination methods were utilized to determining and analyze pollutants such as aldehyde and ketone in environment. In addition, the photochemical reaction statuses of it's precursor compounds were experimentally stimulated. In short, a train of study results were obtained and showed as follows:1. Chromatogram analysis conditions. The chromatographic column was a 4.6 mm x 150 mm x 5 u,m Pecosil-5Cig column. The temperature for chromatographic column was 30 ℃ and the velocity of flow was 1.0 mL/min. Duality grads wash was utilized in the experiments. The flow phase was composed of water and methanol. In the first step of 30 min, the percentage content of methanol varied from 40 % to 80 % and thepercentage content of water varied from 60 % to 20 %; in the second step of 10 min, the percentage content of methanol varied from 80 % to 40 % and the percentage content of water varied from 20 % to 60 %.2. As for formaldehyde, acetaldehyde, acetone, butyraldehyde, aldehyde and benzaldehyde which are hydrazone derivatives, the detection limitation ranges from 0.50 ng to 1.91 ng, linear range locates between 0.05 ng and 223 ng, and the correction coefficients are all beyond 0.9990.3. At the velocity of 0.5 L/min, a tube with 5 mL sorb liquid was used to sample aldehydes and ketones in atmosphere. In the process, the sampling efficiency varied from 97.9 % to 98.7 %. While the dichloromethane was utilized to extract, the efficiency changed from 95.1 % to 101.3 %.4. The data, from the determination on aldehydes and ketones in atmosphere of the campus of Ocean University of China (OUC) and partial areas of Qingdao and in room air of organic chemical laboratory of College of Chemistry and Chemical Engineering at OUC, demonstrated the concentrations of aldehydes and ketones in atmosphere of campus of OUC and partial areas of Qingdao are under the correlative standard of National Environmental Protection Bureau, however the concentrations of these matters in organic chemical laboratory of OUC appreciably are beyond the standard. Determining annual change of aldehydes and keton in atmosphere of the campus of OUC, the concentrations in summer are higher then that in winter.5. As for the photolysis of methanol, there is an abduction period of time. After 20 ~ 40 min of reaction, the concentration of formaldehyde increases more fast, then the product of formaldehyde is also photolyzedwith the decrease of concentration of formaldehyde. The experiments prove that the intensity of lamp-house is proportional to the rate of reaction and the concentration of methanol doesn't strongly influence the reaction rate of formaldehyde from photo-oxidation.6. In the photolysis of ethanol in atmosphere, there are the products of formaldehyde and acetaldehyde. The concentration of acetaldehyde increases earlier than that of formaldehyde does perhaps because acetaldehyde from oxidation is oxidized again and then scissile into formaldehyde.7. In air, photolysis of acetone occurs and the concentration of acetone decreases with prolonging of time, but the decrease isn't proportional to time. In addition, the photolysis of acetone scarcely occurs in high purity nitrogen.8.