Federal University of Uberlândia (UFU), Institute of Chemistry, Uberlândia, MG, Brazil.
Federal University of Uberlândia (UFU), Institute of Chemistry, Uberlândia, MG, Brazil.
Talanta. 2021 Jan 15;222:121558. doi: 10.1016/j.talanta.2020.121558. Epub 2020 Aug 27.
The determination of sulfide anion in a variety of waters (e.g. wastewaters and natural waters) even at low concentration (i.e. in the μM range) is essential due to its high toxicity, corrosivity and unpleasant smelling proprieties. Despite several methodologies are dedicated to aqueous sulfide determination, most of them need sampling/transport steps - which is no adequate to sulfide due to its reactivity and instability - resulting in critical analytical bias. In this study, we present a fully modular and portable 3D-printed platform for in-situ aqueous sulfide determination. The analytical device is based on HS vapor generation from the sulfide sample solution by addition of HPO followed by collection in a miniaturized cuvette (μCuvette) containing few microliters of Fluorescein Mercury Acetate (FMA), a fluorescent dye. The chemical reaction results in fluorescence quenching of the dye at 530 nm when excited at 470 nm. A light-emitted diode (LED) emitting at 470 nm and powered with 9 V-battery based circuitry was employed to provide stable excitation light source at 20 mA. Digital images from the light emitted by FMA were captured by a smartphone and the Green channel intensity was used as analytical signal. Under optimized conditions, a linear relation (r > 0.99) from 0.1 to 5 μM of sulfide was obtained using 10 mL of standard/sample solution. The portable platform was applied to the in-situ monitoring of sulfide in tap water and river water with no loss of analyte, no need for external power supplies or powered pumps. and the analysis results were obtained in 20 min. The proposed device shows advantages in terms of high degree of portability, low-power consumption, easiness to use, minimal use of reagents yet enabling on-site determination of sulfide with high sensitivity. By using the vapor generation approach combined with the modular building blocks concept presented herein for the first time, we anticipate the development of a tailored "plug-and-play" platform enabling the multiplexed determination of volatile substances using absorbance, reflectance or fluorescence measurements with smartphones.
由于其高毒性、腐蚀性和难闻的气味特性，测定各种水体（例如废水和天然水）中的硫化物阴离子，即使在低浓度（即微摩尔范围内）也是必不可少的。尽管有几种方法专门用于测定水溶液中的硫化物，但大多数方法都需要采样/运输步骤 - 这对于硫化物来说是不合适的，因为硫化物具有反应性和不稳定性，这会导致分析偏差。在这项研究中，我们提出了一种完全模块化和便携式的 3D 打印平台，用于现场测定水溶液中的硫化物。该分析装置基于向硫化物样品溶液中加入 HPO 后，通过 HS 蒸气发生，然后将其收集在含有几微升荧光素汞乙酸盐（FMA）的微型比色皿（μCuvette）中。当用 470nm 激发时，化学反应导致染料在 530nm 处的荧光猝灭。采用发射波长为 470nm 的发光二极管（LED），并由基于 9V 电池的电路供电，以 20mA 的电流提供稳定的激发光源。智能手机捕捉到来自 FMA 发射的光的数字图像，并将绿色通道强度用作分析信号。在优化条件下，使用 10mL 标准/样品溶液，可得到 0.1 至 5μM 范围内的硫化物的线性关系（r>0.99）。便携式平台可用于现场监测自来水中的硫化物，无需消耗分析物，无需外部电源或动力泵，且可在 20 分钟内获得分析结果。该设备具有高度便携性、低功耗、易于使用、试剂用量少等优点，同时还具有高灵敏度的现场硫化物测定能力。通过首次使用蒸气发生方法结合本文提出的模块化构建块概念，我们期望开发出一种定制的“即插即用”平台，能够使用智能手机进行吸收、反射或荧光测量，实现挥发性物质的多组分测定。
