# Nanomaterials-Based Ion-Imprinted Electrochemical Sensors for Heavy Metal Ions Detection: A Review
## 3 Application of Nanomaterials in HMIIECSs
### Gold Nanomaterials
\begin{table}
\begin{tabular}{c c c c c c} \hline
**EC Sensing Platform** & **Technique** & **Metal Selectivity** & **Detection Limit** & **Linear Range** & **Ref.** \\ \hline GCE-IIP-MWCNTs & DPV & H\({}_{2}\)\({}^{2+}\) & 5.0 nM & \(1\times 10^{-8}\)-\(7.0\times 10^{-4}\)M & [81] \\ TI-IP-MWCNT-CPE & DPASV & Tl\({}^{+}\) & 0.76 ng/mL & 3.0-240 ng/mL & [82] \\ CPE-IIP-MWCNTs & & Cr\({}^{3+}\) & \(5.9\times 10^{-7}\) M & 1.0 uM-1.0 M & [84] \\ Ce-IIP-MWCNTs & SWV & Ce\({}^{3+}\) & 10.0 pM & 1.0 uM-25 pM & [83] \\ Ag-IIP-MWCNTs & DPV & Ag\({}^{+}\) & \(1.2\times 10^{-10}\) M & \(0.5\times 10^{-9}\)-\(2.8\times 10^{-7}\) M & [85] \\ GCE-IIP-MWCNTs & DPV & Pb\({}^{2+}\) & 0.16 ug/L & 5.0-10.0 ug/L & [86] \\ IIP-MWCNTs-CPE & SWASV & Pb\({}^{2+}\) & 3.8 pM & \(1.0\times 10^{-11}\)-\(8.0\times 10^{-8}\) M & [87] \\ MWCNT-CH-CH\({}_{2}\)-IIP & DPV & Zn\({}^{2+}\) & \(1.2\times 10^{-4}\) mM & 1–5 ppm & [88] \\ MWCNT-CH-CH\({}_{2}\)-IIP & DPV & Cr\({}^{3+}\) & 0.051 M & 1–5 ppm & [89] \\ MWCNT-CH-CH\({}_{2}\)-IIP/PE & DPV & Co\({}^{2+}\) & \(1.01\times 10^{-5}\) uM & 1–5 ppm & [90] \\ MWCNT+CH=CH\({}_{2}\)-IIP/Pt & DPV & Ni\({}^{2+}\) & 0.028 uM & 1–5 ppm & [91] \\ MWCNT-CH=CH\({}_{2}\)-IIP & DPV & Pb\({}^{2+}\) & \(2\times 10^{-2}\) uM & 1–5 ppm & [92] \\ MWCNT-CH=CH\({}_{2}\)-IIP/Pt & DPV & Cd\({}^{2+}\) & 0.03 uM & 1–5 ppm & [93] \\ MWCNT-CH=CH\({}_{2}\)-IIP/Pt & DPV & Mn\({}^{2+}\) & 0.0138 uM & 1–5 ppm & [94] \\ IIP/MWCNT/CS/IL/GCE & SWASVs & Mn\({}^{2+}\) & 0.15 uM & 2.0-0.9 uM & [95] \\ GR-IIM-GCE & i+ & Pd\({}^{2+}\) & \(6.4\times 10^{-9}\) M & \(2.0\times 10^{-8}\)-\(2.0\times 10^{-4}\) M & [100] \\ CS-GR-IIP & DPV & Cr\({}^{6+}\) & \(6.4\times 10^{-10}\) M & \(1.0\times 10^{-9}\)-\(1.0\times 10^{-5}\) M & [62] \\ CS/AuNPs/GR/GCE & DPV & Cd\({}^{2+}\) & \(1.62\times 10^{-4}\) uM & 0.1–0.9 uM & [25] \\ Ag-GR-IIP-CPE & EMF & Zn\({}^{2+}\) & \(1.93\times 10^{-1}\) ug/L & \(2.62\times 10^{-1}\)-\(6.54\times 10^{-5}\) ug/L & [103] \\ GOI-IIP-IDE & & Hg\({}^{2+}\) & 1 ppm & & [105] \\ CS/GO-IIP & DPASV & Cu\({}^{2+}\) & 0.15 uM & 0.5–100 uM & [65] \\ GO-IIP-CCE & ASV & Cd\({}^{2+}\) & \(7\times 10^{-14}\) M & \(4.2\times 10^{-12}\)-\(5.6\times 10^{-3}\) M & [106] \\ GO/MWCNT/IIP & — & Cu\({}^{2+}\) & \(4.0\times 10^{-7}\) M & \(1.0\times 10^{-6}\)-\(1.0\times 10^{-1}\) M & [27] \\ RCO-IIP & SWASV & Hg\({}^{2+}\) & 0.02 ug/L & 0.07-80 ug/L & [109] \\ PPy/FOO/IIP & SWASV & Cd\({}^{2+}\) & 0.26 ug/L & 1–100 ug/L & [67] \\ PoPD/ERGO/IIP/GCE & SWASV & Cd\({}^{2+}\) & 0.13 ng/mL & 1–50 ng/mL & [68] \\ Al\({}_{2}\)O\({}_{3}\)/FOO/IIP & — & Hg\({}^{2+}\) & \(1.95\times 10^{-9}\) M & \(4.00\times 10^{-9}\)-\(1.30\times 10^{-3}\) M & [110] \\ N-GO-CS-IIP & DPV & Cd\({}^{2+}\) & 3.51 nM & 0.01–0.1 uM & [33] \\ GOPTU-IIP & DPV & Hg\({}^{2+}\) & 23.5 nM & \(5\times 10^{-8}\)M–\(2.3\times 10^{-5}\) M & [114] \\ GOPTU-IIP & CV & Hg\({}^{2+}\) & 30.2 nM & \(6\times 10^{-8}\)M–\(8.5\times 10^{-7}\) M and & [114] \\ g-C\({}_{3}\)N\({}_{4}\)/IIP & SWASV & Hg\({}^{2+}\) & 18 pM & 0.06-250 nM & [119] \\ \hline \end{tabular}
\end{table} 
Table 3: Carbon nanomaterials-based HMIIECSs for the detection of HMIs. coefficient was 0.992, and the LOD was 1.43 \(\times\) 10\({}^{-10}\) M. The improved sensor not only had good selectivity and high sensitivity, but also had good repeatability and stability. [PERSON] et al. developed a reliable and disposable electrochemical sensor for sensitive and selective detection of lead ions, which was denoted as imprinted CS/AuNPs/GR/Nafion /MWCNTs/GCE (Pb\({}^{2+}\)-IIP sensor) [66]. The sensing platform was constructed by firstly immobilizing MWCNTs on the surface of GCE, drop coated Nafion, subsequently deposited CS incorporating AuNPs and GR through electrodeposition combining ion imprinting.