  Heavy metal pollution is a severe environmental problem affecting many water
resources. The non-biodegradable nature of the heavy metals such as lead (Pb)
causes severe human health issues, so their cost-effective, sensitive and rapid
detection is needed. In this work, we describe a simple, facile and low cost
modifications of multiwalled carbon nanotubes (MWCNT) and \b{eta}-cyclodextrin
(\b{eta}CD) through non-covalent/physical (Phys) and a covalent Steglich
esterification (SE) approaches. The Phys modification approach resulted Pb
detection with a limit-of-detection (LoD) of 0.9 ppb, while the SE approach
showed an LoD of 2.3 ppb, both of which are well below the WHO Pb concentration
guideline of 10 ppb. The MWCNT-\b{eta}CD (Phys) based electrodes show
negligible interference with other common heavy metal ions such as Cd2+ and
Zn2+. The MWCNT-\b{eta}CD based electrodes were of low-cost owing to their
simple synthesis approaches, exhibited good selectivity and reusability. The
proposed MWCNT-\b{eta}CD based electrodes is a promising technology in
developing a highly affordable and sensitive electrochemical sensing system of
Pb in drinking water.
