Table 1 Highlights of nanosensors for pesticide detection

Fluorescent-nanosensor

3-aminopropyl-triethoxysilane coated Yb₂O₃

Imazapyr

0.2 ppm

Hydrothermal method

Quenching of fluorescence intensity for APTES coated Yb₂O₃ NPs with the increasing concentration of imazapyr

Among the lanthanide oxide based nanomaterials, ytterbium (III) oxide (Yb₂O₃) NPs owes unique optical and luminescence properties with excellent efficiency for real field conditions

[173]

Surface plasmon resonance (SPR) based affinity sensor

Atrazine imprinted nanoparticles

Atrazine

0.7134 ng/mL

Atrazine imprinted nanoparticles synthesis using emulsion polymerization method followed by their attachment on the gold surface of SPR

Increase in resonance frequency in proportion to the increment in atrazine concentration

The plastic antibody-based SPR nanosensor is an attractive recognition element for the detection of atrazine with high selectivity and sensitivity

[174]

Surface plasmon resonance based fiber–optic nanosensor

Tantalum(V) oxide nanoparticles

Fenitrothion

38 nM

Chemical synthesis of Ta₂O₅ nanoparticles embedded in reduced graphene oxide matrix followed by its adhesion on silver-coated fiber optic probe

Change in refractive index due to the interaction of fenitrothion with the silver film

The sensor is selective, repeatable and works at ambient temperature with a response time of 23 s

[175]

Fluorescence sensor

Copper (II) oxide and multiwall carbon nanotubes (MWCNTs)

Glyphosate

0.67 ppb

CuO/MWCNT were prepared by precipitating copper nitrate by the addition of aqueous NaOH solution

Inhibition of the catalytic activity of CuO/MWCNTs

A highly selective & promising approach for rapid screening of glyphosate

[176]

Electrochemical Luminescence sensor

Luminol-gold nanoparticles-L-cysteine-Cu(II) composites

Glyphosate

0.5 nM

Layer-by-layer assembly of graphene-gold nanoparticle composite and Lu-Au-Lcys-Cu(II) composite

Decrease in electrochemical luminescence intensity with a respective increase in the glyphosate concentration

The sensor worked on dual inhibition strategy with excellent detection performance, high sensitivity, desirable reproducibility, stability, and accuracy

[177]

Electrochemical sensor

CuO-TiO2 hybrid nanocomposites

Methyl parathion

1.21 ppb

CuO-TiO₂ nanocomposites prepared by a facile liquid-control-precipitation method were decorated on the glass carbon electrode

Differential pulse voltammetry measurements assessed from decline in current density with increase in the methyl parathion concentration

A non-enzymatic sensor with good stability and excellent reproducibility

[103]

Electrochemical aptasensor

Chitosan-iron oxide nanocomposite

Malathion

0.001 ng/mL

Iron Oxide nanoparticles synthesized using chemical co-precipitation method were deposited on fluorine tin Oxide followed by the immobilization of aptamer onto the iron oxide doped-chitosan/FTO electrode using streptavidin

Decline in the Differential Pulse Voltammetry peak current of the aptaelectrode with a corresponding increase in malathion concentration due to the formation of more 3D-complex between aptamer with malathion

A very attractive alternative to quantify and monitor malathion due to its sensitivity, stability, short analysis time and cost-effectiveness

[110]

Electrochemical nanosensor

CuO nanoparticles decorated 3D graphene nanocomposite

Malathion

0.01 nM

Copper oxide nanoparticles electro-catalyst was prepared on 3D graphene synthesized using hydrothermal process

Decline in peak current with the increasing concentrations of malathion

Highly sensitive, reproducible and applicable in real field conditions

[109]

Optical nanosensor

Silver nanodendrites

Dimethoate

0.002 ppm

Ag nanodendrites fabricated by laser-assisted photochemical method were immobilized on the surface of microsphere end-shape optical fibre

Increase in the intensity of the surface-enhanced Raman spectroscopy (SERS) signal with a proportionate increase in dimethoate concentration

A direct, rapid, real-time and non-destructive method of detecting pesticide residue in the outdoor fields

[107]

Optical sensor

Upconverting nanoparticles (UCNPs) of the NaYF₄:Yb, Er type

Metribuzin

6.8 × 10⁻⁸ M

Upconverting nanoparticles synthesized using the coprecipitation method of lanthanide metal-EDTA complexes were later used in the preparation of the sensor film by dissolving UCNPs in tetrahydrofuran along with the incorporation of NIR dye, PVC polymer, dioctyl phthalate

Metribuzin changes the color of sensor film from green to blue with a significant blue shift in the absorption peak

Highly sensitive sensor with unique luminescence properties of UCNPs and great recognition abilities within a very low detection limit

[108]