Reasearch On High-throughput Screening Methods For Organic Matters In The Workplace

With the development of social economy,there are continuous growing of organic substances used in the manufacturing,transportation and use process of industrial products.Most organic substances usually have high toxicity,persistence and bioaccumulation,which seriously endangers the health of employees.Due to the increasing concern of the whole society about the occupational population.Detection and analysis research of organic compounds in workplace samples,which is one of the major aspects of occupational disease prevention and control,is becoming more and more important.Therefore,the future detecting method with more efficient performances can implement the simultaneous determination of multicomponent.There are a wide variety of organic substances in the workplace,and their physical and chemical properties vary greatly.The volatility of organic compounds determines their state in air,vapor or aerosol particles.There are different air sampling and instruments method for vapor and aerosol particles.According to volatility,workplace organics can be divided into volatile organic compounds（Volatile Organic Compounds,VOCs）and semi-volatile organic compounds（SVOCs）.The current standard analysis method is the National Occupational Health Standard of the People’s Republic of China "Determination of Toxic Substances in Workplace Air".Gas chromatography with poor qualitative ability is overwhelmingly applied for determinating organic compounds in workplace air.However,only a few of target compounds can be effectively detected in one injection.In this thesis,the research on detection of organics in the workplace is carried out.After the collected samples are quickly and effectively extracted by the accelerated solvent extraction ASE.And a sensitive and rapid detection method based on gas chromatography-triple quadrupole mass spectrometry is established.The main research contents include:（1）37 organic compounds including alkanes and chlorinated alkanes,esters,ketones,aromatic hydrocarbons and phenyl ethers are selected as typical volatile organic compounds（VOCs）in the workplace air.And 16 polycyclic aromatic hydrocarbons（PAHs）including fluorene,phenanthrene,anthracene,fluoranthene,Pyrene,benzo [a] anthracene,benzo [b] fluoranthene,benzo [k] fluoranthene,benzo[a] pyrene,indeno [1,2,3-cd] pyrene,dibenzo [a,h] anthracene and benzo [g,h,i]perylene are representative for semi-volatile organic compounds（SVOCs）in the air of workplaces.The vapor of 37 VOCs were collected by the activated carbon tube,and the vapor and aerosol particle of 16 PAHs coexisting in the air are collected by the OVS-2 sampling tube which consists of two parts.The front part of glass fiber filter membrane is for the aerosol state and the back part of XAD-2 is for the vapor state.Two experimental methods,orthogonal design and response surface method,were used to optimize the conditions of accelerated solvent extraction.The effects of extraction temperature,flushing volume,cycle times,and standing time on the extraction efficiency were investigated.A second-order polynomial equation to fit the extraction efficiency and influence factor curve is established based on experimental data.Finally,the optimal extraction conditions for ASE were obtained from the above equation.In order to further improve the precision and sensitivity of the instrument,the optimization of GC-MS/MS analysis was performed.by varying inject mode,temperature programs,the qualitative/quantitative ion pairs and collision voltage.Therefore,the optimized method proved to be successfully applied for the determination by evaluating the linear range,the detection limit and the detection precision.（2）Based on the two above methods,a preliminary database of workplace toxicants was established with built-in information on retention indices,MRM channels（Multiple Reaction Monitoring）,collision energies,and ion ratios of workplace toxicants.The results show that the constructed database can be used to adjust the retention time of target compounds to the current value after single analysis of n-alkane standard solutions in different laboratories using the Automatic Adjustment of Retention Time（AART）function without reference standards,which can quickly achieve a high-throughput GC-MS/MS:MRM method.This method can be used for rapid screening of occupational hazards in workplace air.The screening process is to collect the workplace air with activated charcoal and OVS-2 sampling tubes respectively,and the collected samples are quickly extracted by accelerated solvent extraction ASE,and then the optimal GC-MS/MS:MRM method for screening is automatically created using the database.The method is performed for identifying the organic compounds with occupational hazards in workplace air samples.The achieved positive samples in the screening results were determinated by the corresponding GC-MS/MS:MRM method established again using the database for accurate quantitative analysis of the screened target compounds in the samples.This detection process can achieve a large number of organic compounds,which are identified in a single injection,greatly enhancing the identification capability and efficiency of occupational hazardous organics;and can quickly and accurately establish quantitative detection methods,reducing reference standards consumption and avoiding the cumbersome parameter settings for GC-MS/MS method,improving the speed of analysis.The results shows that the established method for 37 kinds of VOCs and 16 kinds of PAHs is significantly better than the current standard analysis method,which can accelerate solvent extraction and improve the sample extraction efficiency,simplifie the pre-treatment,achieves the general unification and automation,and provide technical guarantee for the analysis of large quantities of samples.This detection method provides a more efficient and sensitive detection means for workplace air.The novel high-throughput screening method established in this work can provide a helpful supplement and complement to detecting qualitative detection of various organic substances,and screening and monitoring the large data of toxicants with occupational hazards in the workplace.