**5. EIS in food analysis**

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 in food products using EIS-based aptamers.

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


**147**

HMs [77].

0.15 nM [79].

*Electrochemical Impedance Spectroscopy (EIS) in Food, Water, and Drug Analyses: Recent…*

Another *Salmonella* sensor was fabricated using a GO/Au NP-modified GCE. The sensor was applied for pork samples and achieved a LoD of 3.0 colony-

(PAMAM G4) and DNA aptamers (on Au electrode) specific to AFB1 [74].

was selective towards *S. enteritidis* and showed a negative response towards mixture of other pathogens [69]. Similarly, the same electrode was used as a sensor for *S. typhimurium* [70]. The developed sensors were capable of differentiating between the targeted *Salmonella* species (S. *enteritidis* and S. *typhimurium*) and the other

The mycotoxin ochratoxin (OTA) has been determined in a variety of samples, e.g., in cocoa beans, using EIS aptasensor developed using a diazonium-coupling reaction mechanism for the immobilization of anti-OTA-aptamer on screen-printed carbon electrode (SPCE) [72]. EIS was also applied for the determination of OTA using a thiolated DNA aptamer immobilized by chemisorption to the surface of Au electrode [73]. Other mycotoxins, e.g., Aflatoxin B1 (AFB1) were detected using layer coating of cystamine (Cys), poly (amido-amine) dendrimers of generation 4.0

Pesticides, e.g., acetamiprid, were determined in samples of vegetables (tomatoes and cucumber) using AgNP-modified nitrogen-doped graphene (AgNPs/ NG). The designed aptasensor was sensitive, selective, and economical and did not

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 permit-

**Table 3** shows examples for the applications of EIS in determination of water

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

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

Other contaminants like pesticides and herbicides as well as drugs and pharma-

ceuticals were also determined using EIS [63, 65, 66, 75, 77] (**Table 3**).

contaminants such as HMs, pesticides, drugs, and pharmaceuticals.

) in this case [71] compared to 600 CFU mL<sup>−</sup><sup>1</sup>

using the

*DOI: http://dx.doi.org/10.5772/intechopen.92333*

*Salmonella*.

forming unit (CFU mL<sup>−</sup><sup>1</sup>

ted levels [23–26, 76].

GNPs@SPCE aptasensors [69, 70].

require intricate labelling procedures [75].

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

#### **Table 2.**

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

*Electrochemical Impedance Spectroscopy (EIS) in Food, Water, and Drug Analyses: Recent… DOI: http://dx.doi.org/10.5772/intechopen.92333*

was selective towards *S. enteritidis* and showed a negative response towards mixture of other pathogens [69]. Similarly, the same electrode was used as a sensor for *S. typhimurium* [70]. The developed sensors were capable of differentiating between the targeted *Salmonella* species (S. *enteritidis* and S. *typhimurium*) and the other *Salmonella*.

Another *Salmonella* sensor was fabricated using a GO/Au NP-modified GCE. The sensor was applied for pork samples and achieved a LoD of 3.0 colonyforming unit (CFU mL<sup>−</sup><sup>1</sup> ) in this case [71] compared to 600 CFU mL<sup>−</sup><sup>1</sup> using the GNPs@SPCE aptasensors [69, 70].

The mycotoxin ochratoxin (OTA) has been determined in a variety of samples, e.g., in cocoa beans, using EIS aptasensor developed using a diazonium-coupling reaction mechanism for the immobilization of anti-OTA-aptamer on screen-printed carbon electrode (SPCE) [72]. EIS was also applied for the determination of OTA using a thiolated DNA aptamer immobilized by chemisorption to the surface of Au electrode [73]. Other mycotoxins, e.g., Aflatoxin B1 (AFB1) were detected using layer coating of cystamine (Cys), poly (amido-amine) dendrimers of generation 4.0 (PAMAM G4) and DNA aptamers (on Au electrode) specific to AFB1 [74].

Pesticides, e.g., acetamiprid, were determined in samples of vegetables (tomatoes and cucumber) using AgNP-modified nitrogen-doped graphene (AgNPs/ NG). The designed aptasensor was sensitive, selective, and economical and did not require intricate labelling procedures [75].
