**6. EIS in water and wastewater analysis**

Discharge of heavy metals (HMs) into the water bodies via industrial activities and other sources, e.g., mining, acid rain, agricultural waste, etc., denotes a worldwide challenge. As previously mentioned in this chapter, HMs and other emergent contaminants possess a significant influence on the environment and human health. The intensifying flux of HMs into aquatic environments and the properties of HMs (toxicity, degradation rates, accumulation, uptake, bioavailability, etc.) necessitate the presence of firm rules and action plans for monitoring, detoxification methodologies, and treatment technologies to keep their concentrations within the permitted levels [23–26, 76].

**Table 3** shows examples for the applications of EIS in determination of water contaminants such as HMs, pesticides, drugs, and pharmaceuticals.

EIS has been applied for quantitative determination of HMs in water samples. In one of the investigations, a bi-enzymatic biosensor was constructed by immobilizing *Arthrospira platensis* cells (Spirulina) on gold interdigitated transducers. Consequently, phosphatase and esterase activities were inhibited by HMs and pesticides, respectively. This approach was used to determine Hg2+ and Cd2+ as well as parathion, paraoxon, and triazine pesticides, alone or in mixture with the HMs [77].

In another approach, a three-electrode sensor was printed on a polyethylene terephthalate film (PET) and was applied for impedimetric determination of Pb2+ and Cd2+ in water samples at nanomolar level [78]. An electrochemical DNA biosensor based on microspheres of cuprous oxide (Cu2O) and nano-chitosan (NC) was used for Hg2+ detection in river water samples with a LoD of 0.15 nM [79].

Other contaminants like pesticides and herbicides as well as drugs and pharmaceuticals were also determined using EIS [63, 65, 66, 75, 77] (**Table 3**).

*Electrochemical Impedance Spectroscopy*

P4 [66].

**5. EIS in food analysis**

in food products using EIS-based aptamers.

**interface**

GCE

modified-SPCE

aptamer

modified electrode

*.*

*Applications of EIS in analysis of food and food products.*

Acetamiprid Ag-NG/GCE GCE Cucumber

*S. enteritidis* GNPs@SPCE SPCE Poultry

*S. typhimurium* GNPs@SPCE SPCE Animal-

**Target Sensing** 

*Salmonella* GO+AuNPs@

OTA Diazonium

OTA Thiolated DNA

AFB1 Cys-PAMAM-

*Colony-forming unit (CFU) mL<sup>−</sup><sup>1</sup>*

Bisphenol A (BPA), a xenoestrogen with an estrogen-mimicking effect and that is widely used as a precursor in plastics industry, has been determined using a labelled aptasensor made of gold nanoparticles (AuNPs), Prussian blue (PB), and

Determination of progesterone (P4) in water and other clinical samples was performed using single-stranded ssDNA aptamers with high binding affinity to

In addition to food contamination with antimicrobials and other drugs, bacteria and other pathogens like mycotoxins (secondary metabolites of microfungi) or chemicals such as pesticides are also other sources of food contamination. Food contamination can occur at any stage of food production, storage, or dissemination. Sicknesses caused by foodborne pathogens include symptoms such as diarrhea, nausea, vomiting, septicemia, meningitis, and even death [50, 53, 67, 68]. Pathogens include famous strains of bacteria such as different species of Salmonella (e.g., *S. enteritidis* and *S. typhimurium*), *Escherichia coli* (*E. coli*), and *Staphylococcus aureus* (*S. aureus*).

**Table 2** shows examples of different bacterial strains that have been determined

**Electrode Matrix Sensing** 

products

based products

beans

products

and corn snacks

and tomatoes **method**

GCE Pork meat EIS 3.0 [71]

**LoD Ref**

EIS 600 [69]

EIS 600 [70]

mL<sup>−</sup><sup>1</sup>

0.40 nM

0.03 nM

pM

[72]

[73]

[74]

[75]

EIS 0.15 ng

EIS 0.12*–*

EIS 0.40 ±

EIS 0.033

A highly specific DNA—aptamer to *S. enteritidis* in pork products—was developed using gold NPs, i.e., modified SPCE (GNPs-SPCE). The developed aptasensor

**Bacteria (LoD is measured as/CFU mL−1)\***

**Mycotoxins**

SPCEs Cocoa

Au Food

Au Peanuts

**Pesticides**

functionalized carbon nanotubes (AuNPs/PB/CNTs-COOH).

**146**

*\**

**Table 2.**


#### **Table 3.**

*Applications of EIS in analysis of water.*
