Electrochemical detection of free chlorine at inkjet printed silver electrodes

Abstract

A low-cost, reliable and sensitive electrochemical method for free chlorine analysis in water using inkjet printed silver electrodes is presented. Free chlorine detection was based on linear sweep voltammetry (LSV) analysis of AgCl/Ag 2 O films formed over an inkjet printed silver electrode by the spontaneous reaction between silver and free chlorine species (i.e. HClO and ClO − ) present in solution. The formation of AgCl/Ag 2 O films was studied and characterized by high resolution scanning electron microscopy (HR SEM) and X-ray photoelectron spectroscopy (XPS) techniques. LSV characterization demonstrated a quantitative linear relationship between the amount of AgCl/Ag 2 O formed and the concentration of free chlorine in water within a range from 1 to 100 ppm. After optimization of several parameters (e.g. scan rate, reaction time, starting potential), lowest detectable free chlorine concentration was 0.4 ppm (by standard addition method), while the limit of detection (S/N = 3) was equal to 2 ppm, with a sensitivity of 30 μC/ppm. The validation of the proposed methodology was performed by comparison with the standard N,N-diethylparaphenylenediamine (DPD) method for analyzing swimming pool water samples. Finally, it was demonstrated that reproducible and disposable silver electrodes could be easily prepared by inkjet printing in a large scale and in any required geometry to fit on-line and onsite free chlorine analyses requirements.

Highly Loaded Mildly Edge‐Oxidized Graphene Nanosheet Dispersions for Large‐Scale Inkjet Printing of Electrochemical Sensors

“…Ag or Ag/AgCl were used as QRE. For Ag/AgCl, silver electrodes were exposed for 3 min to a sodium hypochlorite solution . All three electrodes (WE, QRE, CE) had an active area of theoretically ∼1 mm 2 (the real electrode area was ∼0.7 mm 2 due to the typical broadening of the insulation ink pattern prior to its complete polymerization).…”

Preparation and electrochemical performance of uniform RuO2/Ti and RuO2‐IrO2/Ti electrode for electrolysis of NaCl solution

“…Chemical agents, such as ozone and other chemical materials, inactivate a special enzyme of the microorganism, or degrade the cytoplasm of the bacteria through an oxidation reaction. Recently, Cl 2 , NH 4 Cl, ClO 2 , O 3 , and NaClO have been commonly used as disinfecting agents. NaClO has acceptable solubility in water, can be dissolved with water in any ratio, and have no disinfection by‐products that are toxic or harmful to human health.…”

Inkjet-printed microtiter plates for portable electrochemical immunoassays

“…Recently, inkjet printing has become an attractive alternative for microfabrication. It is an additive manufacturing technique that enables the mask-and contact-less deposition of a variety of functional materials, such as metal and metal oxide nanoparticles, organometallic compounds, conductive polymers, carbonaceous materials, protein microarrays and living cells with high accuracy and micrometer resolution using picoliter droplets [24][25][26][27][28][29][30][31][32][33][34][35]. The advantages of IJP include low ink waste, easily changeable layouts and the possibility of multi material deposition to create material gradients and multi-layer devices [36][37][38].…”

“…Moreover, IJP can reduce the overall fabrication time and costs of an entire device due to the possibility of rapid iterative design changes during the sensor development stage and due to the up-scalability of the production rate from the prototype to the industrial level. In this way, IJP has been used for the fabrication of a broad range of chemical sensors based on gold on paper [39][40][41] as well as polymer substrates [27,42,43], silver [30,44] polyaniline [45,46] or CNTs [47][48][49][50]. CNTs are attractive functional materials for sensing platforms due to several advantageous CNT properties, such as good electrical conductivity, chemical and mechanical stability, high flexibility, electrocatalytic activity and reduced surface fouling characteristics for specific applications [51][52][53][54].…”