Internal Calibration Potentiometric Aptasensors for Simultaneous Detection of Hg²⁺, Cd²⁺, and As³⁺ Based on a Screen-Printed Carbon Electrodes Array

Abstract

An all-solid-state potentiometric aptasensor array based on a multichannel disposable screen-printed carbon electrode (SPCE) was demonstrated for the simultaneous detection of Hg, Cd, and As by open circuit potential (OCP) technology. The potential of the channel with an internal calibration DNA sequence (IC-DNA) was employed as the internal calibration potential (ICP) to subtract the background signal generated by the detection system, providing a built-in correction methodology. As a result, the developed aptasensor array showed high sensitivity and accuracy for detecting Hg, Cd, and As without mutual interference or interference from other ions. The linear response ranged from 2.5 pM to 2.5 μM, and the detection limits for Hg, Cd, and As were 2.0, 0.62, and 0.17 pM, respectively. Furthermore, the potentiometric aptasensor array was successfully applied for the simultaneous detection of three ions in real samples. The results obtained from the developed approach agreed well with the results obtained from inductively coupled plasma mass spectrometry.

From Small Molecules toward Whole Cells Detection: Application of Electrochemical Aptasensors in Modern Medical Diagnostics

“…An aptasensor was developed for the simultaneous determination of heavy metal ions (Hg 2+ , Cd 2+ , and As 3+ ) using potentiometry [84]. A multichannel screen-printed carbon electrode array was used as a transducer, with electrodes modified with rGO and gold dendrimers.…”

Please Avoid Plotting Analytical Response against Logarithm of Concentration

“…Positive and negative examples of the use of logarithmic and semilogarithmic calibration plots can be found in the recent literature. Some reports relate analytical response with logarithm of concentration (or activity), − while others use a nonlinear (logarithmic) concentration axis. − Usefulness of the former representation in quantitative analysis is limited. The latter may (in some cases) be defensible if a logarithmic dependency is expected for a particular technique, and the authors do not claim “linearity”.…”

Bio- and Biomimetic Receptors for Electrochemical Sensing of Heavy Metal Ions

“…As for other folding-and dynamics-based electrochemical biosensors, multiple uses (up to three) were possible by introducing a regeneration step. To address the need of portable devices, researches focused on the development of highly sensitive aptasensors based on screen-printed electrodes (SPE) [74,94]. Li et al [94] proposed a simple label-free aptasensor on gold SPE using the issAP08_Cd 2+ aptamer with a thiol linker as a bioreceptor.…”

“…A potentiometric aptasensor array for the simultaneous detection of Cd 2+ and Hg 2+ was developed by Tang et al [74]. A multichannel disposable screen-printed carbon electrode (SPCE) modified with reduced graphene oxide and dendritic nanostructured gold was used to increase the stability and the effective area of SPCE channels.…”