Recent Advances in Ion-Selective Membrane Electrodes for In Situ Environmental Water Analysis
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Keywords: ion-selective membrane electrodes, ion monitoring, environmental analysis, water research, in situ ion detection 1. Introduction A significant need for collecting chemical data in natural water systems with higher temporal and spatial resolution, in comparison with traditional sampling protocols, has been highlighted as a major priority by the European Union (Water Framework Directive).[1] A comprehensive review by Namour et al. addresses this important issue within a legal framework and presents evidence on certain environmental estimators that largely vary in less than 1 h.[1] Therefore, it may be extremely relevant to develop methodologies that fulfil within this time window (and also with sufficient spatial resolution) in view of providing more accurate chemical information. This will not only be significant to the generation of scientific knowledge but will also impact such applications’ potential societal value. For example, understanding ongoing natural biogeochemical processes, monitoring the process of primary production (photosynthesis and chemosynthesis) and respiration, correlation of natural cycles with anthropogenic activities, epidemiology studies and water quality control among others would all be enhanced. Finally, a remote-sensing platform may 3 be used as a strategic alarm to identify contaminations or toxic spills that could damage a water system (e.g., the 2000 contamination of Danube River by cyanide) Blaen et al. [2] recently assessed “real-time monitoring of nutrients in rivers”, claiming that the inadequate sampling frequencies result in missing pulses of nutrients during short-term events as well as underestimation of long-term nutrient fluxes. Thus, the manner by which to extract that information from natural resources seems not yet efficient and this may be considered a serious issue impeding obtaining complete and reliable information on the ecosystem. Currently, natural water reservoirs are regularly sampled and then analysed via centralized laboratories. Under favourable conditions, the concentration profiles are provided in weeks. To put this into context, once the samples are extracted, certain additives and preservatives are added to the prefiltered samples on the sampling platform. Then, the samples are ready to be transported to centralized laboratories under controlled temperature and ultraclean conditions. In the laboratory unit, certain additional pretreatments are required (e.g. adjustment of pH and ionic strength, desalination in the case of seawater samples, centrifuging, etc.)[3] before the analysis, which consists of using costly instrumentation, such as atomic absorption/emission spectroscopy (AAS/AES), ion-chromatography (IC), inductively coupled plasma mass spectrometry (ICP –MS), ion analysers, spectrophotometric tests, etc., operated by a trained laboratory assistant. tải về 1.01 Mb. Chia sẻ với bạn bè của bạn:
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