Multisensory System Used for the Analysis of the Water in the Lower Area of River Danube.

Constantin Apetrei,Lucian Puiu Georgescu,Catalina Iticescu

doi:10.3390/nano9060891

Constantin Apetrei, Lucian Puiu Georgescu + Show 1 more

Open Access

https://doi.org/10.3390/nano9060891

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Abstract

The present paper describes the development of a multisensory system for the analysis of the natural water in the Danube, water collected in the neighboring area of Galati City. The multisensory system consists of a sensor array made up of six screen-printed sensors based on electroactive compounds (Cobalt phthalocyanine, Meldola’s Blue, Prussian Blue) and nanomaterials (Multi-Walled Carbon Nanotubes, Multi-Walled Graphene, Gold Nanoparticles). The measurements with the sensors array were performed by using cyclic voltammetry. The cyclic voltammograms recorded in the Danube natural water show redox processes related to the electrochemical activity of the compounds in the water samples or of the electro-active compounds in the sensors detector element. These processes are strongly influenced by the composition and physico-chemical properties of the water samples, such as the ionic strength or the pH. The multivariate data analysis was performed by using the principal component analysis (PCA) and the discriminant factor analysis (DFA), the water samples being discriminated according to the collection point. In order to confirm the observed classes, the partial least squares discriminant analysis (PLS-DA) method was used. The classification of the samples according to the collection point could be made accurately and with very few errors. The correlations established between the voltammetric data and the results of the physico-chemical analyses by using the PLS1 method were very good, the correlation coefficients exceeding 0.9. Moreover, the predictive capacity of the multisensory system is very good, the differences between the measured and the predicted values being less than 3%. The multisensory system based on voltammetric sensors and on multivariate data analysis methods is a viable and useful tool for natural water analysis.

Highlights

The Danube is a vital river for Europe, forming one of the largest and most important water systems on the continent
In order to analyze the responses of the voltammetric sensors when exposed to water samples from the Danube, the voltammetric responses of all the sensors exposed to the same water sample and the responses of a sensor exposed to all water samples to be analyzed will be discussed
A multisensory system was developed for monitoring the Danube water quality along sampling points and for estimating some physico-chemical parameters by using the PLS1 regression models

Summary

Introduction

The Danube is a vital river for Europe, forming one of the largest and most important water systems on the continent. The Danube has played a major role in the socioeconomic, political and cultural development of central and south-eastern Europe for centuries, and the people living in the Danube area still use this river for drinking water, irrigation, hydroelectric power, naval transport, recreation, etc. The concentration of water pollutants and water quality are determined by using systems based on different physico-chemical detection principles, most of these methods being standardized [6,7,8]. The systems capable of determining in situ and of reporting on-line changes in water quality need to be used in order to improve water quality monitoring, as well as to control the operations in water treatment plants [9,10]. Classical analytical methods can be used to determine water quality with high accuracy, but such methods are expensive (equipment, reagents), require long time analysis and highly qualified staff and imply off-line determinations

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