| Volatile organic compounds(VOCs)that come from different sources and have complex components are one of the main pollutants in water.They not only have harmful effect on human health,but also pose a serious threat to the surrounding ecological environment.Therefore,the detection and analysis of VOCs in water is of great significance for ensuring people’s health and environmental safety.Environmental water quality monitoring work is usually required to be completed in a relatively short period of time,especially in the face of sudden water quality pollution events or detection of volatile substances,how to further develop high sensitivity,detection speed detection methods,is the key to effectively respond to the detection of environmental pollution in water.In this study,a novel unmanned ship-borne on-line mass spectrometer mobile monitoring system based on the combination of on-line mass spectrometry with other detection techniques was designed and built.In the meantime,an analytical methods for detective VOCs was established and used to detect standard and actual samples.In order to verify the validity of this method,the results obtained by this method were compared with that of laboratory analytical methods(Purge and capture/gas chromatography-mass spectrometry,P&T-GC MS),and the precision and accuracy obtained by two method were comparable.It verifies the reliability of the platform built and the analytical method established in this study.The main works were listed as follows:1.An unmanned ship-borne on-line mass spectrometer mobile monitoring system for detective VOCs in water was design and built.The system consisted of seven parts:an unmanned ship,a set of multi-channel sampling equipment,water quality monitoring equipment,the switch,power supply system,data acquisition system and the remote control.It can automatically travel on the water surface according to the designed route,and send the monitoring results to the computer on the base station to conduct real-time and on-site VOCs analysis.2.An analytical methods for detective VOCs was established.In this method,a peristaltic pump was used to extract the sample into the chamber,and the mass-tocharge ratio in the mass spectrum was used to qualitatively analysis,and the peak intensity applied to quantitatively analysis.The conditions for implementing the method were optimized.3.Standard samples containing 21 VOCs were determined using the system.The range of the minimum detection limit was 0.31 μg/L-1.26 μg/L,and the linear correlation coefficients of all components were greater than 0.99,indicating that the response value of each component had a good linear correlation with the content of the standard solution.When pure water and natural lake water were spiked with 10μg/L and 80 μg/L,respectively,the precision of most target compounds was less than10%,and the accuracy was between 80% and 110%.4.The method was compared with a laboratory analytical method(P&T-GC MS).The linear correlation coefficients of the standard curves of the two detection methods were equivalent,both greater than 0.99,meeting the requirements of the national standard method.The results of the standard addition and recovery comparison experiments of pure water and natural lake water showed that the measurement precision and accuracy results of the two detection methods were comparable,and they all met the standard requirements of <30% precision of the target compounds,and the matrix spiked recoveries were at the level of 60%-130%.5.The unmanned ship-borne on-line monitoring system built in this study was applied to the water quality monitoring of an actual water area for pollution profiling,realizing the detection of VOCs in water by this system,and providing important technical and data support for effectively ensuring water quality safety.In summary,this study provides a solution for efficient on-line monitoring of VOCs categories and concentrations in water. |
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