On dithiothreitol (DTT) as a measure of oxidative potential for ambient particles: evidence for the importance of soluble transition metals.
On dithiothreitol (DTT) as a measure of oxidative potential for ambient particles: evidence for the importance of soluble transition metals.
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DOI：
10.5194/acpd-12-11317-2012
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发表时间：
2012-05-03
影响因子：
6.3
通讯作者：
Anastasio C
中科院分区：
文献类型：
--
作者：
Charrier JG;Anastasio C
二硫苏糖醇（DTT）的消耗率越来越多地用于测量颗粒物（PM）的氧化潜力，这与PM的不良健康影响有关。虽然已知几种醌在DTT测定中具有很强的反应性，但尚不清楚其他哪些化学物质可能导致PM提取物中DTT的损失。为了解决这个问题，我们量化的DTT损失率从个别氧化还原活性物种是常见的环境颗粒物。虽然大多数过去的研究表明，DTT检测对金属不敏感，但我们的结果表明，测试的十种过渡金属中有七种确实会氧化DTT，测试的五种醌中有三种也会氧化DTT。虽然与最具反应性的醌类相比，金属氧化DTT的效率较低，但细颗粒物中可溶性过渡金属的浓度通常远高于醌类。最终的结果是，金属似乎占主导地位的DTT响应典型的环境PM2.5样品。基于文献中醌类和可溶性金属的颗粒浓度，以及我们对这些物质的DTT响应测量，我们估计，对于典型的PM2.5样品，约80%的DTT损失来自过渡金属（特别是铜和锰），而醌类约占20%。我们发现了一个类似的结果DTT损失测量的一小部分PM2.5样本从圣华金河谷的加州。由于金属的重要贡献，我们还测试了DTT测定如何受到EDTA的影响，EDTA是一种有时用于测定的螯合剂。EDTA可显著抑制金属和醌类的响应;因此，我们建议DTT试验中不应包括EDTA。
The rate of consumption of dithiothreitol (DTT) is increasingly used to measure the oxidative potential of particulate matter (PM), which has been linked to the adverse health effects of PM. While several quinones are known to be very reactive in the DTT assay, it is unclear what other chemical species might contribute to the loss of DTT in PM extracts. To address this question, we quantify the rate of DTT loss from individual redox-active species that are common in ambient particulate matter. While most past research has indicated that the DTT assay is not sensitive to metals, our results show that seven out of the ten transition metals tested do oxidize DTT, as do three out of the five quinones tested. While metals are less efficient at oxidizing DTT compared to the most reactive quinones, concentrations of soluble transition metals in fine particulate matter are generally much higher than those of quinones. The net result is that metals appear to dominate the DTT response for typical ambient PM2.5 samples. Based on particulate concentrations of quinones and soluble metals from the literature, and our measured DTT responses for these species, we estimate that for typical PM2.5 samples approximately 80 % of DTT loss is from transition metals (especially copper and manganese), while quinones account for approximately 20 %. We find a similar result for DTT loss measured in a small set of PM2.5 samples from the San Joaquin Valley of California. Because of the important contribution from metals, we also tested how the DTT assay is affected by EDTA, a chelator that is sometimes used in the assay. EDTA significantly suppresses the response from both metals and quinones; we therefore recommend that EDTA should not be included in the DTT assay.