The Novel Method Of C₁₈ Membrane Extraction-gas Chromatography/Mass Spectrometry Detection Of Polycyclic Aromatic Hydrocarbons In Hailuogou Snow

Polycyclic aromatic hydrocarbons (referred to as PAHs) are one kind of thepersistent organic pollutants (pops), which have the characteristics such as strongcarcinogenicity, semi-volatile and refractory. Thus makes them widely exist in variousenvironmental medium, also, they can enrich in soil, water, animals and plants, ashuman are at the top of the food chain, PAHs might ultimately affect our health.Therefore, the development of a fast and effective method to detect PAHs has a greatsignificance to understand their environmental pollutant status. Establishment of suchkind of method can prevent and control the environment and finally guarantee thehealth of entire human race.Currently, the study of PAHs in snow and ice have been systematic studied inmountain snow and Polar Regions. The results show that human activities at lowlatitudes and low altitude produce PAHs, and they can easily migrate along with theatmosphere to high altitude areas. When the temperature decreases, PAHs go back tothe ground with snow, and enrich in high latitudes. But when the temperature increases,the part of PAHs would evaporate into the atmosphere, to migrate again; with themelting of the ice and snow, other part would flow into the freshwater systems anddamage to plants and animals. Therefore, the study of PAHs in Hailuogou snow and iceis necessary. By reading a large number of references and related standard methods, thispaper established a C18solid phase extraction membranes-gas chromatography-massspectrometry method to detect16kinds of PAHs in Hailuogou snow samples.This paper established GC/MS detection PAHs in Hailuogou snow and ice, byusing high separation and high sensitivity appraisal ability of GC/MS. Throughoptimization, the final instrument detection conditions were determined. Chromatographic conditions: HP-5MS capillary column (30m×250μm×0.25μm); thecarrier gas for high purity helium (purity99.999%or higher); injection porttemperature290℃; no sample shunt way, pressure as follows:23.878psi; constantcurrent mode, carrier gas flow rate of2mL/min. Oven temperature programmed: initialtemperature of100℃keep1min, at a rate of10℃/min to240℃, maintain5minutes,and then at a rate of20℃/min to280℃keep8min. Injection volume:1.0μL. Massspectrometry conditions: electro-Impact source (EI); electron energy is70eV; Ionsource temperature230℃; MS quadropole temperature150℃; interface temperature280℃; solvent delay2min. Measurement model: full scan/selected ion monitoringscan, mass scan range0-500amu.Because the C18solid phase extraction membrane has high selectivity, goodextraction efficiency, less solvent consumption, higher enrichment efficiency and otheradvantages, so C18membrane was used to extract16kinds of polycyclic aromatichydrocarbons in Hailuogou snow. This research studyed the influencing factors ofextraction efficiency, such as the variety and dosage of organic modifier, sample rate,the variety and dosage of eluent on, and then obtained optimum pretreatment conditions.Qualitative and quantitative analysis of PAHs in pure water samples (contains threedifferent concentration mixed standard PAHs4L pure water) was carried out underC18-GC/MS selective ion monitoring mode, the detection limit was0.00063-0.011μg/L. The calibration curves of the methods are in good linearity. The averagerecoveries ranged between78.03%-99.81%,81.63%-95.79%and76.31%-94.04%respectively, and relative standard deviations (RSD) were measured to be2.70%-7.51,4.81%-10.27%and6.59%-12.86%, they basically reached the requirements EPA525.5standard methods. This method is applied to detect Hailuogou snow, can achieve goodresults, can satisfy requirements for determination of of PAHs in Hailuogou snow andice.By using the optimized experimental conditions, this experiment successfullydetected of PAHs in Hailuogou snow. The analysis results show that the snow and icesample mainly contain2-4ring PAHs, whose content was223.5ng/L-246.7ng/L, andwere much more than other parts of the qinghai-tibet plateau. This research alsodetected of PAHs in the end of glacier melt water and forest park water of Hailuogou,the results showed that the content is slightly lower than Hailuogou snow sample, thekinds of polycyclic aromatic hydrocarbons in water were less than the kinds in snowsample, but they were mainly low molecular weight PAHs.This paper provides a novel analysis method to detect PAHs in Hailuogou snow, lay the foundation to Hailuogou PAHs monitoring and pollution prevention in future.