| Environmental pollution becomes more and more serious with the rapid development of economy.The air particulate matters not only affect visibility,climate change,but also are found to be a potential health risk for human body.Especially,organic pollutants which are adsorbed on air particulate matter have more harmful influence to human health.In recent years,the study of organic pollutants in air particulate matter has become a research focus on worldwide.In this study,16 polycyclic aromatic hydrocarbons and 15 nitro polycyclic aromatic hydrocarbons in air particulate matter were extracted and purified by integrated ultrasonic extraction technique.These analyzes were quickly and reliabiy detected by gas chromatography-electron impact ionization mass spectrometry(GC-EI-MS)and gas chromatography-negative ion chemical ionization mass spectrometry(GC-NCI-MS).In this research,integrated ultrasonic extraction and purification were chosen as pretreatment method and special morphology Mg-Al layered double oxide(Mg-Al-LDO)was used as absorbent in pretreatment procedure.A series of experimental conditions for the extraction solvent,extraction time,extraction solvent volume were systematically studied and optimized.Owing to the superior ability in purification,type of adsorbents,filling way of adsorbents,volume and type of elution solvent also were optimized.The conditions of the proposed method as follows:the extraction solvent was 15 mL hexane/DCM(1:1,v/v).The extraction time was 20 min.In order to obtain a satisfactory recovery,Silica gel(0.5 g)and Mg-Al-LDO(0.5 g)were chosen as the suitable adsorbents and 12 mL hexane/DCM(3:7,v/v)was selected as elution solvent.According to optimized conditions,recoveries were from 88.9 to 116.3%and from 81.6 to111.3%for 16 PAHs and 15 NPAHs in spiked samples,respectively.And the spiked concentrations for 16 PAHs and 15NPAHs were 100,500,1000 ng·g-1 and 50,200,400 ng·g-1,respectively.The relative standard deviations(RSDs)were less than 6.5%of all cases.The method showed excellent linearity and correlation coefficients(r2)were between 0.9992 and 0.9999 for all analyzes.The limits of detection(LODs)of 16 PAHs and 15 NPAHs ranged from 0.02 to 1.72 ng g-1 and 0.03 to 0.60 ng g-1,respectively.And limits of quantifications(LOQs)were from 0.06 to 5.74 ng g-1 and 0.12 to 2.00 ng g-1 for 16 PAHs and 15 NPAHs,respectively.This analytical method was applied to actual total suspended particulate samples collected in June and December,Beijing,China,2015,respectively.The results indicated that the quick,easy and reliable method could be used to determinate PAHs and NPAHs in air particulate matter.In addition,the paper also carried out applied research on benzo(a)anthracene(BaA)and benzo(a)pyrene(BaP)in green tea.And the mothod was applied to international comparison for detecting green tea samples.Accelerate solvent extraction(ASE)was used as extraction method.And the purification procedure was gel permeation chromatography(GPC)combined with solid phase extraction(SPE),then samples were analyzed by GC-EI-MS.The ASE extraction conditions,such as extraction cycles,extraction time,extraction solvent or extraction temperature,were thoughly optimized to achieve effective extraction.Meanwhile,in order to get satisfactory purification,the collection time for GPC,type of SPE column,elution solvent and volume for SPE were also optimized.Finally,the method was applied to detect concentrations of BaA and BaP in international comparison of green tea samples.Concentrations for BaA and BaP were 66.79 ng g-1 and 52.36 ng·g-1,respectively and the RSD less than 0.85%.The result was within given reference concentration range(50-80 ng g-1).It was proved that the developed method is sensitive,accurate and reliable for determination of PAHs in green tea samples.The international comparison is significant for international mutual recognition of the calibration and measurement ability between China and other participating countries in the world. |
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