Electrochemical Study of Carbon Nanotubes/Nanohybrids for Determination of Metal Species Cu²⁺ and Pb²⁺ in Water Samples

Table 2

Comparison of parameters and LOD of the different modified electrodes for determination of metal ions, including Cu(II) and Pb(II), using DPASV method.

Species	Electrolyte	Study electrode versus reference	Potential and deposition time	LOD (μg L^−1)	Reference
Pb^2+, Cu^2+, Cd^2+, Tl^+	0.1 M HCl	GC with HgF 25 mg L^−1 and BiF 0,5 mg L^−1  versus Ag/AgCl	−1.4 V for 60 s	HgFE 0.10, 0.15, 0.050, 0.70; BiFE , 5.10 were found for Pb^2+, Cu^2+, Cd^2+, Tl^+, respectively.	De Carvalho et al., 2008 [29]
Pb^2+, Cu^2+, Cd^2+, Hg^2+	KCl pH 3	Modified carbon paste electrode based on BTPSBA  versus saturated calomel electrode	−1.1 V for 300 s	8.28, 12.7, 50.4, 80.4 were found for Pb^2+, Cu^2+, Cd^2+, Hg^2+, respectively.	Cesarino et al., 2008 [30]
Pb^2+, Cu^2+, As^3+, Hg^2+	0.1 M HCl with 0.5 M NaCl	Au versus Ag/AgCl	−1.2 V for 32 s	0.2, 0.07, 0.4, 0.07 were found for Pb^2+, As^3+, Cu^2+, Hg^2+, respectively.	Alves et al., 2011 [31]
Zn^2+, Cu^2+, Hg^2+, Pb^2+	0.5 M NaCl with 1.0 mM HCl	Gold microwire versus Ag/AgCl	−2 V for 30 s	0.2, 0.3, 0.4, 0.4 for Zn^2+, Cu^2+, Hg^2+, Pb^2+, respectively.	Alves et al., 2013 [32]
Cu^2+, Pb^2+, Cd^2+, Zn^2+	0.5 M acetate buffer pH 1	BDD  versus Ag/AgCl	−0.95 V for 240 s	0.37, 0.40, 1.28, 0.16 were found for Cu^2+, Pb^2+, Cd^2+, Zn^2+, respectively.	Honório et al., 2014 [33]
Pb^2+, Cu^2+, Cd^2+	pH 4.5	CB-18-crown-6-GEC  versus Ag/AgCl	−1.4 V for 120 s	1.5, 1.5, 2.4 were found for Pb^2+, Cu^2+, Cd^2+, respectively.	Serrano et al., 2015 [27]
Cd^2+, Pb^2+, Cu^2+	0.1 M pH 4.7 acetate buffer solution	Mo6SxI9-x NWs/GC  versus saturated calomel electrode	−1.1 V for 240 s	0.10, 0.45, 0.20 were found for Cd^2+, Pb^2+, Cu^2+, respectively.	Lin et al., 2015 [28]
Pb^2+ and Cu^2+	0.01 M KNO3 pH 4,5	SbSPCE  versus Ag/AgCl	−0.7 V for 120 s	4,8 and 0,28 were found for Pb^2+ and Cu^2+, respectively.	Sosa et al., 2015 [34]
Cu^2+, Hg^2+, Pb^2+	0.1 M NaCl pH 7	Polyviologen films versus Ag/AgCl	−0.7 V	63.0, 200.0, 207.0 were found for Cu^2+, Hg^2+, Pb^2+, respectively.	Gadgil et al., 2016 [24]
Pb^2+ and Cu^2+	0.1 M HCl	GC/CNT/nanoAu-SiO2  versus Ag/AgCl	−0.8 V for 300 s	0.47 and 0.34 were found for Pb^2+ and Cu^2+, respectively.	This work

BDD: boron-doped diamond.
BTPSBA: 2-benzothiazolethiol organofunctionalized SBA-15 nanostructured silica.
CB-18-crown-6-GEC: 4-carboxybenzo-18-crown-6 assisted by lysine on aryl diazonium salt monolayers anchored to the surface of graphite, epoxy composite electrode.
Mo6SxI9-x NWs: molybdenum-chalcogenide-halide nanowires (NWs), which are composed of molybdenum (Mo), sulfur (S), and iodine (I) in the form of Mo6S9_xIx (MoSI).
SbSPCE: antimony film screen-printed carbon electrode.