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A pilot study found that DDT breakdown at the GC inlet was extensive in extracts from some--but not all--samples with high organic carbon contents. However, DDT losses could be prevented with a one-step extraction-cleanup in the Soxflo instrument with dichloromethane and charcoal. This dry-column procedure took 1 h at room temperature. It was tested on spiked soil and peat samples and validated with certified soil and sediment reference materials. Spike recoveries from freshly spiked samples ranged from 79 to 111% at 20-4000 microg/kg concentrations. Recoveries from the real-world CRMs were 99.7-100.2% of DDT, 89.7-90.4% of DDD and 89.6-107.9% of DDE. It was concluded that charcoal cleanups should be used routinely during surveys for environmental DDX pollution in order to mitigate against unpredictable matrix-enhanced breakdown in the GC. 相似文献
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利用高分辨气相色谱/高分辨质谱联用仪(HRGC/HRMS)和高分辨气相色谱/低分辨质谱仪(HRGC/LRMS)对实际生物样品中二恶英(polychlorinated dibenzo-p-dioxins and dibenzofurans,PCDD/Fs)的分析过程中13C标记的2,3,7,8-四氯代二苯并呋喃(13C12-2,3,7,8-TCDF)监测碎片离子通道的两个常见干扰峰进行了分析鉴定。通过实际样品分析结果首先推测这两个干扰峰可能为有机氯农药类化合物滴滴涕(DDT)降解产物滴滴伊(DDE)的两个异构体,其次采用DDE的标准溶液(包括o,p’-DDE和p,p’-DDE)进行分析确认。通过HRGC/HRMS的色谱峰分离效果分析、色谱保留时间匹配以及与DDE碎片离子的理论丰度比进行比较,最终确认实际样品分析中的两个干扰峰依次为o,p’-DDE和p,p’-DDE。本文可为生物样品中二恶英的准确识别提供重要参考。 相似文献
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将大型结构静,动力分析有限元程序JIFEX移植到WINDOWS95平台,利用DDE客户/服务器机制实现了实时跟踪处理的可视化技术,并可以进一步实现计算过程的实时控制干预。 相似文献
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本文主要介绍了以MapInfo为GIS开发平台,VB为系统开发前台,基于DDE的GIS系统的集成技术. 相似文献
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介绍了一种基于Winsock技术的C/S(Client/Server)模式下实现两种协议融合并存的消防远程监控系统。利用Winsock技术实现TCP/IP(Transmission Control Protocol/Internet Protocol)协议与原系统DDE(Dynamic Data Exchange)协议的融合,降低系统对于Lonworks技术的依赖性,减少系统内部的不良耦合,消除系统中的不稳定因素,使系统稳定可靠地运行,同时也可降低软件开发的成本。 相似文献