Lo Ching, Buan Eric, Li James, Zhang Wei
Environmental Applied Science and Management, Ryerson University, 350 Victoria Street, Toronto, Ontario, M5B 2K3, Canada.
Ontario Ministry of the Environment, Laboratory Services Branch, 125 Resources Road, Etobicoke, Ontario, M9P 3V6, Canada.
Anal Bioanal Chem. 2016 Feb;408(4):1095-105. doi: 10.1007/s00216-015-9205-1. Epub 2015 Dec 4.
The use of an enzyme-linked immunosorbent assay (ELISA) to screen for polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) has shown promise as a complementary tool to gas chromatography-high resolution mass spectrometry (GC-HRMS). This is especially true due to its low cost, ease of sample preparation and fast sample turnaround time. One problem that was unaddressed by other research is how to increase the efficiency of ELISA to a point that makes it practical for the analysis of large groups of samples that can have a wide range of unknown PCDD/F concentrations; one ELISA test is unable to screen for PCDD/F concentrations that can range anywhere from background levels to upwards of 10,000 picograms toxic equivalents per gram of soil (pgTEQ g(-1)). This paper resolves this problem by introducing a sample algorithm which enables the correct amount of dioxin to enter an ELISA tube from a sample (whose unknown PCDD/F concentration can range between 30 and 10,500 pgTEQ g(-1)) in only two ELISA runs. In doing so, the time and cost benefits of ELISA are preserved. ELISA results for soils and sediment samples processed using the algorithm were then plotted on two site maps alongside their GC-HRMS counterparts. A comparison of both analytical methods showed that areas of high and low PCDD/F concentrations were equally identifiable with either analytical tool; 29 of 32 sample locations on the site maps were placed into the same of three possible screening levels. Therefore, processing ELISA samples through the sample algorithm achieves the necessary level of efficiency while producing virtually equal screening results in comparison to GC-HRMS but at a fraction of the cost. The agreement between GC-HRMS and ELISA was 94% (R (2) = 0.99, n = 53). GC-HRMS and ELISA results were significantly correlated (Wilcoxon signed rank test p < 0.001).
使用酶联免疫吸附测定法（ELISA）筛查多氯二苯并 - 对 - 二恶英和多氯二苯并呋喃（PCDD/F）已显示出有望成为气相色谱 - 高分辨率质谱法（GC - HRMS）的补充工具。由于其成本低、样品制备简便且样品周转时间快，尤其如此。其他研究未解决的一个问题是如何将ELISA的效率提高到使其适用于分析大量具有广泛未知PCDD/F浓度的样品的程度；一次ELISA测试无法筛查出PCDD/F浓度范围从背景水平到每克土壤超过10,000皮克毒性当量（pgTEQ g(-1)）的样品。本文通过引入一种样品算法解决了这个问题，该算法仅通过两次ELISA运行就能使正确量的二恶英从样品（其未知PCDD/F浓度范围在30至10,500 pgTEQ g(-1)之间）进入ELISA管。这样做时，ELISA的时间和成本优势得以保留。然后，将使用该算法处理的土壤和沉积物样品的ELISA结果与对应的GC - HRMS结果一起绘制在两张现场地图上。两种分析方法的比较表明，高PCDD/F浓度区域和低PCDD/F浓度区域使用任何一种分析工具都同样可识别；现场地图上32个采样位置中的29个被归入三个可能的筛查水平中的同一水平。因此，通过样品算法处理ELISA样品可达到必要的效率水平，同时与GC - HRMS相比产生几乎相同的筛查结果，但成本仅为其一小部分。GC - HRMS和ELISA之间的一致性为94%（R (2) = 0.99，n = 53）。GC - HRMS和ELISA结果显著相关（Wilcoxon符号秩检验p < 0.001）。
