Use of pyrolyzed paper as disposable substrates for voltammetric determination of trace metals

Abstract

The possibility of using pyrolyzed paper as disposable working electrodes for trace metals determination is reported for the first time. A small piece of pyrolyzed paper (0.7×0.7cm) was positioned at the bottom side of the electrochemical cell using a rubber O-ring, which defined the electrode area (0.48cm; 0.18cm). A large number of electrodes can be obtained from a single piece of standard dimensions (2.5cm×7.5cm) of paper, therefore minimizing the cost per unit. The electrochemical performance of the pyrolyzed paper was demonstrated by cyclic voltammetry, electrochemical impedance spectroscopy and by the determination of Zn, Cd, and Pb by square-wave anodic stripping voltammetry. The unmodified pyrolyzed paper showed excellent performance for Pb and Cd detection (LOD =0.19 and 0.16 ppb, respectively). In the presence of Bi(in-situ film formation), the simultaneous determination of Zn, Cd and Pb was also possible (LOD=0.26, 0.25, and 0.39 ppb, respectively).

Stripping Voltammetry for the Real Time Determination of Zinc Membrane Diffusion Coefficients in High pH: Towards Rapid Screening of Alkaline Battery Separators

“…It should also be noted that Hg(II) hydrolyzes at high pH to form insoluble hydrated mercury oxides; therefore, this is another advantage for using Bi over Hg in situ electrodes . Moreover, Bi‐film electrodes have been validated many times in the literature for their detection of Zn in aqueous media . In fact, other studies have shown that the Zn stripping peak is only observed in the presence of Bi in the solution .…”

Low Cost Layer by Layer Construction of CNT/Chitosan Flexible Paper‐based Electrodes: A Versatile Electrochemical Platform for Point of Care and Point of Need Testing

“…Although, we found that our paper electrodes are better in terms of electrode cost, they are flexible and they do not need to be electrochemical, physical or chemical activated before the analysis as it was shown that happen with screen printed electrodes . Pyrolyzed paper electrodes present several advantages as low cost, easy fabrication, LOD and linear range for Pb detection , which can be a promising option for laboratory applications. However, they present certain limitations for PON application because they are fragile, they could be broken during shipping or the intended use in the adverse conditions usually found when performing analytical work outside a regular laboratory.…”

“…The guidelines of the World Health Organization set a safe threshold of Pb in drinking water below 10 ppb . For Point of Need applications disposable electrodes modified with Bi film for heavy metal detection were recently studied .…”

Square‐wave Voltammetric Determination of Propyphenazone, Paracetamol, and Caffeine: Comparative Study between Batch Injection Analysis and Conventional Electrochemical Systems

“…In the tests performed in the conventional electrochemical system (steady‐state solution), sample or standard solutions were added directly to an electrochemical cell (≈ 25 mL). In this cell, the working electrode area is also defined using a rubber O‐ring, similar to the procedure when pyrolysed paper was used as working electrode .…”