A screen-printed Ag/AgCl reference electrode with long-term stability for electroanalytical applications

Development of New Simple Compositions of Silver Inks for the Preparation of Pseudo-Reference Electrodes

“…The stability of the potential of the pseudo-reference electrodes was evaluated in the interval of 1 h by the OCP technique. This methodology was similar to those demonstrated in the articles by Dawkins et al and by Søpstad et al [ 7 , 12 ]. A two-electrode system was used as follows: Ag|AgCl|KCl(sat.)…”

“…This is relevant in electrochemical systems because potential deviations can generate changes in the electron transfer rate of the target reaction, which can promote unwanted secondary reactions of electrolyte constituents and even the electrode material itself [ 6 ]. Therefore, the potential of the reference electrode must exhibit low variations during its lifetime (usually potential variations less than 30 mV are acceptable) [ 7 ], and silver inks are affordable alternatives to achieve this stability.…”

“…It is known that despite this lack of equilibrium, the potential of the pseudo-reference electrode can be surprisingly constant during experiments, being an interesting aspect to be explored in the development of simple and disposable devices [ 10 , 11 ]. In the literature, some proposals for making reference electrodes can be found using silver, such as those developed by Dawkins et al and by Søpstad et al [ 7 , 12 ]. Also, we can highlight devices using commercial silver inks, such as those developed by Lan et al and Moya et al [ 8 , 13 ], who studied the design of reference electrodes using paper as a substrate and inkjet printing, respectively.…”

“…Although there are some methodologies involving the use of systems with only carbon as a reference electrode, it is noted that this substrate without silver ink coating has low potential stability so that considerable variations can occur along the time [ 20 , 25 , 26 , 27 ]. Thus, the development of conductive silver inks for building more stable pseudo-reference electrodes is a fantastic approach to enabling large-scale production at reduced cost [ 7 , 12 ]. In this context, the present work reports the development of two Ag conductive inks through the dispersion of Ag powder in shellac and nail polish.…”

What Is the Optimal Method for Cleaning Screen-Printed Electrodes?

“…Compared to the other studied methods, the H 2 O 2 /CV treatment gave good results for both gold and platinum electrodes, as demonstrated by the I m and R p values, while also preventing degradation in the silver reference electrode. It is a well-known fact that the reliability of the reference electrode is crucial for potentiometric and voltametric measurements [20]. One disadvantage of the H 2 O 2 /CV and negative sweeping methods is the time it takes to perform the sweeping, especially if more than 2 are required, due to the very low scan rate (10 mV/s).…”