Department of Oceanography/MA-RE Institute, University of Cape Town, Rondebosch, 7701 Cape Town, South Africa.
Sensors (Basel). 2012 Oct 10;12(10):13583-97. doi: 10.3390/s121013583.
Wherever measurements have been made bromoform was found to be ubiquitous in the surface ocean in pmolar-nmolar concentrations. These measurements show concentrations in coastal regions orders of magnitude higher than in the pelagic oceans. Its atmospheric presence is primarily due to its release from algae and rapid transport to the marine boundary troposphere where it is known to participate in ozone chemistry via photochemical and catalytic pathways. Until quite recently, a limited number of studies existed (compared to other marine volatile organic compounds (VOCs)), mainly due to the analytical challenge(s) presented by the low environmental mixing ratios. In this work we detail the development of a simplified, cost effective method to detect and quantify bromoform in environmental air samples. Air samples (1.5 L) were preconcentrated onto a precooled adsorbent (Carbopack X/Carboxen 1016) trap. These samples were injected by means of rapid thermal desorption for separation and detection by GC-ECD. The system was calibrated by means of a custom-built permeation oven. A linear system response was achieved, having a detection limit of 0.73 ± 0.09 ppt. A range of environmental samples was analysed to demonstrate the ability of the technique to separate and identify bromoform from air samples. The results showed that bromoform concentrations typically averaged 24.7 ± 17.3 ppt in marine air samples, 68.5 ± 26.3 ppt in Cape Town urban air samples and 33.9 ± 40.5 ppt in simulated biomass burning plumes (SBBP).
溴仿在表层海洋中以 pmolar-nmolar 的浓度普遍存在，这一点在已有的测量中得到了证实。这些测量结果表明，沿海地区的浓度比开阔海洋中的浓度高出几个数量级。它在大气中的存在主要是由于它从藻类中释放出来，并迅速传输到海洋边界对流层，在那里它通过光化学和催化途径参与臭氧化学。直到最近，由于环境混合比低带来的分析挑战，相对于其他海洋挥发性有机化合物（VOCs），开展的研究数量有限（相比其他海洋挥发性有机化合物（VOCs））。在这项工作中，我们详细介绍了一种简化、经济有效的方法来检测和量化环境空气中的溴仿。将空气样品（1.5 L）预浓缩到预冷的吸附剂（Carbopack X/Carboxen 1016）捕集器上。这些样品通过快速热解吸进行注射，然后通过 GC-ECD 进行分离和检测。该系统通过定制的渗透烤箱进行校准。实现了线性系统响应，检测限为 0.73±0.09 ppt。分析了一系列环境样品，以证明该技术能够从空气中分离和识别溴仿。结果表明，海洋空气中溴仿的浓度通常为 24.7±17.3 ppt，开普敦城市空气中的浓度为 68.5±26.3 ppt，模拟生物质燃烧羽流（SBBP）中的浓度为 33.9±40.5 ppt。
