Determination Of N-PAHs And SCCPs By SPME Coupled To GC-NCI/MS

Persistent organic pollutants（POPs）are synthetical organic compounds.Because of its persistence,POPs can bioaccumulate through food chain and do adverse impacts to environment and human.In this study,two kinds of solid phase microextraction（SPME）method were developed to analyze short-chain chlorinated paraffins（SCCPs）and nitro polycyclic aromatic hydrocarbon（N-PAHs）in samples with different matrixes.Porphyrinic zirconium metal-organic framework（PCN222）and hollow microporous organic network（H-MONs）were selected as adsorbents and deposited on the stainless steel fibers.The characters were analyzed by scanning electron microscopy,transmission electron microscopy,powder X-ray diffraction and thermogravimetric analysis.The technical feasibility was demonstrated through methodology experiments and real sample analysis.The results are as follows:（1）In this Letter,an in situ hydrothermal growth of porphyrinic zirconium MOF（PCN-222）on stainless steel fibers was fabricated for SPME.The PCN-222（Zr）was uniformly deposited on the fiber and demonstrated exceptional thermal and chemical stability.A SPME analytical method coupled with gas chromatography–negative chemical ionization mass spectrometry was developed to quantify nitrated polycyclic aromatic hydrocarbons（NPAHs）in water samples.Limits of detection（LODs,S/N=3）and limits of quantification（LOQs,S/N=10）of 17 selected analytes ranged from 0.10 ng·L^-1to 20.0 ng·L^-1 and from0.40 ng·L^-1 to 50.0 ng·L^-1,respectively.Linear range was from 0.4 ng·L^-1 to 400 ng·L^-1.Intra-and inter-day reproducibility values obtained from a single fiber（six replicates）ranged from 2.2%–12.8%and 3.6%–12.1%,respectively.Fiber-to-fiber reproducibility for six parallel fibers ranged from 3.3%to 10.3%under the same working conditions.The PCN222@SPME fiber has higher enrichment factors in comparison to three commercial SPME fibers（PDMS、DVB/CAR/PDMS、Carboxen/PDMS）.The developed method was successfully applied for analysis of NPAHs in environmental water,atmospheric particulate matter(PM_2.5),and soil samples.This work demonstrated a prominent prospect of PCN222for the applications in extraction techniques.（2）Chlorinated paraffins（CPs）are mixtures with thousands of isomers and homologues which can not be separated by capillary gas chromatography totally.In the study,SCCPs in samples with different matrixes were analyzed by working curve of chlorinated degree and total response factor.The SCCPs were analyzed by gas chromatography combined with negative chemical ionization mass spectrometry（GC-NCI/MS）,because the response of SCCPs in negative chemical ionization mass spectrometry was higher than that in electron ionization mass spectrometry,The stable fibers were fabricated by a direct coating method using silicone sealants.To maximize the response of targeted analytes,experimental conditions,including extraction temperature,extraction time,ionic strength and pH were optimized through response surface methodology.Under the optimal parameters,the established method showed prominent experimental performance.Method detection limits（3-times standard deviation）were 0.03 ng·m L^-1 in water,0.11 ng·g^-1 in sediments,0.43 ng·g^-1in fish and 0.02 ng·m^-3 in PM_2.5 samples.Linear range was from 0.05 to 10 ng·mL^-1 with high correlation coefficient（r²）of 0.9989.The repeatability and reproducibility were evaluated by relative standard deviation（RSD%）,ranging from 4.6 to 11.0%.The proposed method was successfully applied to simultaneous analysis of SCCPs from water,sediments,organisms and PM_2.5 samples.This work exhibited excellent prospect of MONs for application of extraction techniques.