Barbosa Segundo Inalmar D, Cardozo Jussara C, Castro Pollyana Souza, Gondim Amanda D, Dos Santos Elisama V, Martínez-Huitle Carlos A
Renewable Energies and Environmental Sustainability Research Group, Institute of Chemistry, Federal University of Rio Grande do Norte, Campus Universitário, Av. Salgado Filho 3000, Lagoa Nova, Natal, RN CEP 59078-970, Brazil.
Institute of Chemistry, Federal University of Rio Grande do Norte, Av. Salgado Filho 3000, Lagoa Nova, Natal, RN CEP 59078-970, Brazil.
MethodsX. 2023 Jul 26;11:102300. doi: 10.1016/j.mex.2023.102300. eCollection 2023 Dec.
Aiming the decentralization of monitoring policies and to facilitate the work of researchers, mainly in developing countries, the present method deals with the explanation of a simple and rapid protocol for chemical oxygen demand (COD) analysis through the use of digital smartphone devices coupled with a camera and a free app available for Android operating system that recognizes HSV (hue, saturation, value). The calibration of the method is done based on the theoretical values of potassium hydrogen phthalate for a proper and reliable build of the calibration curve by using the smartphone-based technique and the digested samples of COD. The coefficient of determination (R) attained a value upper than 0.99, providing a high confidence levels, and the method achieved 97% of average accuracy in samples with COD values ranging from 0 to 150 mg L. Finally, the procedure here presented can be a great support for scientific laboratories and monitoring policies, once it can efficiently substitute expensive spectrophotometers and can improve and ensure the sustainable management of water sanitation, which is one of the sustainable goals proposed by the United Nations.•COD measurements, based on the use of a simple smartphone with a camera, can be a promising way for environmental analysis when spectrophotometers are not available, such as decentralized approaches.•The use of smartphone protocol is a novel initiative to fulfill sustainable development goal 6 on clean water and sanitation.•The smartphone is capable to read the difference of HSV values efficiently and can substitute the use of expensive spectrophotometers.
为了实现监测政策的分散化并便于研究人员开展工作，主要是为发展中国家的研究人员提供便利，本方法介绍了一种简单快速的化学需氧量（COD）分析方案，该方案通过使用配有摄像头的数字智能手机设备以及一款适用于安卓操作系统的免费应用程序来实现，该应用程序可识别HSV（色调、饱和度、明度）。该方法的校准基于邻苯二甲酸氢钾的理论值，通过使用基于智能手机的技术和COD消解样品，以正确可靠地构建校准曲线。决定系数（R）的值高于0.99，提供了高置信水平，并且该方法在COD值范围为0至150mg/L的样品中平均准确度达到了97%。最后，本文提出的程序可为科学实验室和监测政策提供有力支持，因为它可以有效替代昂贵的分光光度计，并可改善和确保水卫生的可持续管理，这是联合国提出的可持续发展目标之一。
•基于使用带摄像头的简单智能手机进行COD测量，在没有分光光度计的情况下，如分散式方法，可能是一种很有前景的环境分析方法。
•使用智能手机方案是实现关于清洁水和卫生设施的可持续发展目标6的一项新举措。
•智能手机能够有效地读取HSV值的差异，并可替代昂贵的分光光度计的使用。
