Simple-to-use and Portable Device for Free Chlorine Determination Based on Microwave-Assisted Synthesized Carbon Dots and Smartphone Images

DAMIÁN URIARTE; EZEQUIEL VIDAL; ANTONIO CANALS; CLAUDIA E. DOMINI; MARIANO GARRIDO

Roma

Congreso; 4th PortASAP Meeting; 2021

Universidad de Sapienza

A new portable and simple 3D printed device was disegned for free chlorine determination in water samples. Chlorination is one of the most widely used desinfection processes because it is simple and inexpensive. However, chlorine must be used with care, as it can react with naturally occurring organic species to produce different disinfection byproducts (DBPs), with trihalomethanes (THMs) and haloacetic acids (HAAs) being the main DBPs, wich are considered as carcinogenic. The free residual chlorine is defined as the sum of dissolved Cl2, HClO and ClO-, and it is normally expressed as mass of Cl2 by liter (mgL-1 of ppm). The analytical method was based on the quenching caused by free chlorine on the fluorescence emission of the carbon dots (CD) synthesized from citric acid and urea. The fluorescence was captured through the camera of a smartphone, which was coupled to the 3D printed device, and the images were processed using the RGB system by the ImageJ 1.51q software. The proposed method was selective and precise (RSD% 4.6 for n=6), and the trueness of the results was evaluated by comparing the results obtained with those recovered by the spectrophotometric method 4500-Cl G (standard method), with good agreements between them. The new method and the related portable device could be considered a fast, economical and reliable alternative for the on-site determination of free chlorine in water samples.