Tripeptide Derivative-Modified Glassy Carbon Electrode: A Novel Electrochemical Sensor for Sensitive and Selective Detection of Cd2+ Ions

Tayyaba Kokab; Afzal Shah; Jan Nisar; Asad Muhammad Khan; Sher Bahadar Khan; Aamir Hassan Shah

doi:10.1021/acsomega.0c00760

Tripeptide Derivative-Modified Glassy Carbon Electrode: A Novel Electrochemical Sensor for Sensitive and Selective Detection of Cd²⁺ Ions

ACS Omega. 2020 Apr 22;5(17):10123-10132. doi: 10.1021/acsomega.0c00760. eCollection 2020 May 5.

Authors

Tayyaba Kokab¹, Afzal Shah^{1

2}, Jan Nisar³, Asad Muhammad Khan⁴, Sher Bahadar Khan⁵, Aamir Hassan Shah⁶

Affiliations

¹ Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan.
² Department of Chemistry, College of Science, University of Bahrain, Sakhir 32038, The Kingdom of Bahrain.
³ National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar 25120, Pakistan.
⁴ Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, Abbottabad 22060, Pakistan.
⁵ Department of Chemistry, King Abdulaziz University, Jeddah 21589, Saudi Arabia Kingdom.
⁶ Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States.

Abstract

A N-[(Benzyloxy)carbonyl]-l-alanyl-l-prolyl-l-leucine-N-cyclohexylcyclohexanamine (Cbz-APL) tripeptide-coated glassy carbon electrode (GCE)-based sensor was used for sensitive and selective recognition of cadmium ions in environmental water. Detailed cyclic voltammetric and electrochemical impedance spectroscopic studies were performed to investigate the charge transfer and sensing activity of the developed electrochemical sensor. Square wave anodic stripping voltammetry (SWASV) was employed to further investigate the sensitivity, selectivity, validity, and applicability of the developed sensor. A sharp electrochemical signal of oxidized Cd at -0.84 V versus Ag/AgCl provides evidence for the higher sensing ability of Cbz-APL/GCE than bare GCE at -0.79 V. Moreover, on Cbz-APL/GCE, extraordinary low detection limits of 4.34 fM and linearity range of 15 nM to 0.1 pM with coefficients of correlation higher than 0.99 for Cd²⁺ were achieved. Besides, the influence of inorganic and organic interferents on the targeted analyte signals was examined, and high selectivity of Cbz-APL/GCE for Cd²⁺ ions was observed. Lastly, the validity and applicability of the developed electrochemical sensor for the detection of Cd²⁺ ions were checked in real water samples, and 100% recovery was obtained.