在线GC-MS测定城市环境油气挥发指示物种戊烷的数据异常排查方法  

Key species assessment method based on urban VOCs data characteristics-a case study of n-isopentane

作　　者：张倩华 梁永健 张金谱 林洁萍 林素萍 黄坤伦 Zhang Qianhua;Liang Yongjian;Zhang Jinpu;Lin Jieping;Lin Suping;Huang Kunlun(Guangzhou Sub-branch of Guangdong Ecological and Environmental Monitoring Center,Guangzhou 510006,China;Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary,Guangzhou 510275,China;Guangzhou OnePoint Environmental Consultant Co.,Ltd.,Guangzhou 510220,China)

机构地区：[1]广东省广州生态环境监测中心站,广州510006 [2]广东省环珠江口气候环境与空气质量变化野外科学观测研究站,广州510275 [3]壹点环境科技(广州)有限公司,广州510220

出　　处：《分析仪器》2024年第6期59-67,共9页Analytical Instrumentation

基　　金：国家重点研发计划项目(2022YFC3700400);广东省科技计划项目(科技创新平台类)(2019B121201002)资助。

摘　　要：基于广州市番禺市桥站点在线GC-MS测得的2023年1月至6月VOCs数据,从时间变化特征、站点性质、质量控制等方面,分析汽油挥发指示物种正戊烷、异戊烷监测数据合理性,给出了异常数据合理性判断及排查方法。分析结果表明:1)由于异戊烷高值超出监测系统有效定量范围,定量准确性下降,导致同一污染源影响下,异戊烷的高值表现更为突出,相比正戊烷更不稳定,但不影响作为指示物种;2)站房停电、设备频繁开关机、故障等情况致使在线GC-MS运行状态不稳定,清洗离子源等重要维护动作使设备性能提升,均会影响内标响应与校准曲线斜率,使其发生较大变化;3)数据审核工作应当按照数据审核技术指南中的相关要求开展,但当审核时发现个别指标持续偏离规范要求时,应当组织开展问题核查与数据质量评估工作,结合当地数据特征,制定本地化审核规则与要求;4)由于环境监测市场的多元化发展,VOCs监测设备多种多样,设备性能各有优劣,需定期开展在线、离线监测设备的比对工作,进一步验证仪器性能。Based on VOCs data of Guangzhou Panyu City station from January to June,2023,the rationality of monitoring data for gasoline volatilization indicator species n-pentane and isopentane was analyzed from the aspects of time change characteristics,station nature and quality control,and the rationality judgment and investigation method for abnormal data were summarized to demonstrate the rationality of VOCs data.The analysis results showed that:1)Because the high value of isopentane exceeded the effective quantitative range of the monitoring system and the quantitative accuracy decreased,the high value of isopentane was more prominent under the influence of the same pollution source and was more unstable than that of n-pentane,but it did not affect its use as the indicator species;2)Unstable operation of the equipment caused by power failure,frequent switching on and off of the equipment,failure,etc.,and the improvement of equipment performance caused by important maintenance such as ion source cleaning would affect the internal standard response and calibration curve slope,resulting in great changes;3)Data audit work should be carried out in accordance with the relevant requirements of the data audit technical guidelines,but when individual indicators continue to deviate from the requirements of the standard,problem verification and data quality assessment work should be organized,combined with local data characteristics,formulate localized audit rules and requirements;4)Due to the diversified development of the environmental monitoring market,VOCs monitoring equipment was diverse,and the equipment performance had its advantages and disadvantages.It is recommended to regularly compare of online and offline monitoring equipment to further verify instrument performance.

关 键 词：数据质量 特征 校准 内标 正/异戊烷 

分 类 号：X831[环境科学与工程—环境工程]