**4.1 Biosensors for pesticides and toxin analysis**

Jiang et al. proposed an aptamer-based biosensor for the detection of acetamiprid [59]. To increase the sensitivity of the system silver nanoparticles, decorated nitrogen-doped graphene (NG) nanocomposites were used. This aptasensor exhibited a linear response in the range of 0.1 pM–1.0 nM and a detection limit of 0.01 pM. Zehani et al. developed two impedimetric biosensors for the detection of diazinon in aqueous medium using two different types of lipase, conjugated with BSA, immobilized onto functionalized gold electrodes [69]. Diazinon is one of the most commonly used organophosphate pesticides in the world, and lipase is used to specifically catalyze the hydrolysis of diazinon into diethyl phosphorothioic acid and 2-isopropyl-4-methyl-6-hydroxypyrimidine. The developed biosensors both presented linearity up to 50 μM with detection limit of 10 nM for *Candida rugosa*-based biosensor and 0.1 μM for porcine pancreas-based biosensor. They also studied the reproducibility and stability. Pichetsurnthorn et al. used nanoporous impedance-based biosensor for the detection of pesticide atrazine from river water [70]. To enhance the sensitivity of the system, nanoporous alumina was overlaid on the base surface of the metal electrode. The limit of detection for the detection of atrazine in river water and in drinking water was 10 fg/ml.

Zhang et al. constructed a three-dimensional (3D) graphene-based biosensor for microcystin-LR (MC-LR) detection and quantification in drinking water [54]. Microcystin-LR is a toxin produced by cyanobacteria. EIS was used for the electrochemical characterization of the biochemical action on the electrode-specific anti-MC-LR monoclonal antibodies for the selective detection of MC-LR. A detection limit of 0.05 mg/l was achieved, which is lower than that allowed limit proposed by the World Health Organization (WHO) (1 mg/l).

### **4.2 Biosensors for bacterial analysis**

Mutreja et al. used impedimetric immunosensor for the detection of bacteria *Salmonella typhimurium* in water with detection limit 101 CFU/ml [71]. Graphenegraphene oxide screen-printed electrodes were functionalized with anti-OmpD antibodies to capture *Salmonella typhimurium* through its outer membrane protein OmpD. Barreiros dos Santos et al. presented an EIS-based biosensor for the detection of pathogen *Escherichia coli* O157:H7 in water [72]. The immunosensor detection limit was 2.0 CFU/ml, and linear working range was 10–104 CFU/ml. Rengaraj

**59**

**Analyte** Acetamiprid

Wastewater

Aptamer with the following sequences: 5′-(SH)-(CH2)6-

TGTAATTTGTCTGCAGCGGT

TCTTGATCGCTGACACCATAT

TATGAAGA-3′

Lipase from *Candida rugosa*

(CRL); lipase from porcine pancreas (PPL)

Anti-atrazine antibodies

Nanoporous alumina membrane integrated with printed circuit board platform

10 fg/ml

—

10 fg/ml–1 ng/

[70]

ml

Functionalized gold electrode

10 nM (CRL); 0.1 μM (PPL)

(RSD) 2–5%

2–50 μM

[69]

Diazinon

Atrazine

River and bottled drinking water

Microcystin-LR

Local tap

Monoclonal microcystin

3D-graphene-based

0.05 μg/l

6.9% inter- and 3.6%

0.05–20 mg/l

[54]

(R2 0.939)

intra-assay coefficients

of variability

biosensor (Ni/graphene

composites coated with a

PMMA solution)

Graphene-graphene oxidemodified screen-printed

101 CFU/

—

—

[71]

ml

carbon electrodes

Functionalized gold

2 CFU/ml

(RSD) 2% (n = 3)

10–104 CFU/

[72]

ml

103–107 CFU/ ml

[73]

electrode

Functionalized screenprinted electrode

103 CFU/ ml

antibodies (against ADDA,

AD4G2, mouse IgG1)

water

(toxin produced by

cyanobacteria)

*Salmonella* 

Water

Anti-OmpD antibodies

*typhimurium* species

Pathogen *Escherichia* 

Water

Anti-*E. coli* antibodies

*coli* O157:H7

Bacteria

**Table 1.**

*The application, characteristics, and construction of impedance biosensors used in water analysis.*

Water

Lectin *concanavalin A*

River water

Silver nanoparticles (NPs) decorated with nitrogen-

33 pM

(RSD) 6.9% (n = 5)

10 pM–5 nM

[59]

doped graphene (NG) nanocomposites

**Sample**

**Recognition element**

**Electrode**

**LOD**

**Reproducibility**

**Response range**

**References**

*Challenges and Applications of Impedance-Based Biosensors in Water Analysis*

*DOI: http://dx.doi.org/10.5772/intechopen.89334*


*Challenges and Applications of Impedance-Based Biosensors in Water Analysis DOI: http://dx.doi.org/10.5772/intechopen.89334*

> **Table 1.**

*The application, characteristics, and construction of impedance biosensors used in water analysis.*

*Biosensors for Environmental Monitoring*

frequent measurement [65].

conjugated protein, the latter generated a measured signal 40–50 times higher and the limit of detection 64 times lower [68]. MacKay et al. also used Au-NPs to evaluate the sensing ability of biosensor chips using impedance measurements and found that the adsorption of Au-NPs to the surface binding sites increased the impedance through double-layer capacitance and higher sensitivity is gained using single

A range of different EIS-based biosensing technologies for the detection of pollutants like pesticides and pathogens in water samples have been developed. A condensed overview of these biosensors including a brief description of the biosensor working principles, limit of detection, working range, and reproducibility is given in **Table 1**. Although not all these devices have been commercialized, they

Jiang et al. proposed an aptamer-based biosensor for the detection of acetamiprid [59]. To increase the sensitivity of the system silver nanoparticles, decorated nitrogen-doped graphene (NG) nanocomposites were used. This aptasensor exhibited a linear response in the range of 0.1 pM–1.0 nM and a detection limit of 0.01 pM. Zehani et al. developed two impedimetric biosensors for the detection of diazinon in aqueous medium using two different types of lipase, conjugated with BSA, immobilized onto functionalized gold electrodes [69]. Diazinon is one of the most commonly used organophosphate pesticides in the world, and lipase is used to specifically catalyze the hydrolysis of diazinon into diethyl phosphorothioic acid and 2-isopropyl-4-methyl-6-hydroxypyrimidine. The developed biosensors both presented linearity up to 50 μM with detection limit of 10 nM for *Candida rugosa*-based biosensor and 0.1 μM for porcine pancreas-based biosensor. They also studied the reproducibility and stability. Pichetsurnthorn et al. used nanoporous impedance-based biosensor for the detection of pesticide atrazine from river water [70]. To enhance the sensitivity of the system, nanoporous alumina was overlaid on the base surface of the metal electrode. The limit of detection for the detection of

Zhang et al. constructed a three-dimensional (3D) graphene-based biosensor for microcystin-LR (MC-LR) detection and quantification in drinking water [54]. Microcystin-LR is a toxin produced by cyanobacteria. EIS was used for the electrochemical characterization of the biochemical action on the electrode-specific anti-MC-LR monoclonal antibodies for the selective detection of MC-LR. A detection limit of 0.05 mg/l was achieved, which is lower than that allowed limit proposed by

Mutreja et al. used impedimetric immunosensor for the detection of bacteria

graphene oxide screen-printed electrodes were functionalized with anti-OmpD antibodies to capture *Salmonella typhimurium* through its outer membrane protein OmpD. Barreiros dos Santos et al. presented an EIS-based biosensor for the detection of pathogen *Escherichia coli* O157:H7 in water [72]. The immunosensor detec-

CFU/ml [71]. Graphene-

CFU/ml. Rengaraj

**4. Applications of EIS-based biosensors in water analysis**

have been successfully tested in the laboratories.

**4.1 Biosensors for pesticides and toxin analysis**

atrazine in river water and in drinking water was 10 fg/ml.

the World Health Organization (WHO) (1 mg/l).

*Salmonella typhimurium* in water with detection limit 101

tion limit was 2.0 CFU/ml, and linear working range was 10–104

**4.2 Biosensors for bacterial analysis**

**58**

et al. fabricated an impedimetric paper-based biosensor for the detection of bacterial contamination in water [73]. They used lectin *concanavalin A* as a bioselective element due to its stability to interact with mono- and oligosaccharides on bacterial cells. The detection limit was approximately 1000 CFU/ml.
