Electrochemical sensing of lead in drinking water using β-cyclodextrin-modified MWCNTs

A simple, facile and low-cost modification of multiwalled carbon nanotubes (MWCNT) with β-cyclodextrin (βCD) through a physical (Phys) and a covalent approach via Steglich esterification (SE) is demonstrated for the detection of lead (Pb). The Pb sensing performance is governed by the amount of βCD present in the MWCNT-βCD matrix and the physical/chemical attachment of βCD with MWCNT. The physically modified MWCNT-βCD based electrode showed high sensitivity of 98 nA/ppb with a limit of detection of 0.9 ppb but poorer reliability, whereas the chemically modified MWCNT-βCD electrode results in moderate sensitivity of 38.6 nA/ppb and a limit of detection of 2.3 ppb. The modified sensors showed reproducibility of more than 90% and reusability of at least six times. The proposed sensors offer a promising technology in developing a highly affordable and sensitive electrochemical sensing system for monitoring the Pb level in drinking water.