Abstract

Automated Cu(II) Monitoring over a Wide Concentration Range with Microflow Injection Analysis System Employing Modular 3D-Printed Platforms

David Ricart Fort, PhD student, Escola Politècnica Superior d'Enginyeria de Manresa. EPSEM

An automated modular multi-step photometric microflow injection analysis (microFIA) system has been developed for the continuous Cu(II) measurement in a bioreactor. The system combines multiple 3D printed modules, such as a disperser, a chelation mixer, a diluter provided with a Tesla valve to connect with a reduction mixer and a detector provided with a LED light source and LDR light intensity detector. A Tesla valve was used as a 3-way solenoid valve, positioned before the detector, to introduce ethanol after each measurement without the necessity of moving parts. Detection of Cu(I) is performed, after reduction of Cu(II), by measuring the colour intensity of the complex formed between Cu(I) and neocuproine. The microFIA system has proven to work well across a wide concentration range, from 34 to 2000 mg L-1 in a continuous and automatic way. The apparatus exhibits a great reproducibility and repeatability (with a coefficient of variation less than 2% throughout the concentration range) as well as nearly 100% accuracy in the linear response range, 600–1900 mg·L-1 Cu(II). When the microFIA system and an atomic absorption spectroscopy approach were compared to analyse real samples, no statistically significant differences between two methods were found.