# Turning Waste into Sensors: Sustainable Pesticide Detection Using Orange Peel-Derived Laser-Induced Graphene

## TL;DR

This paper introduces a low-cost pesticide sensor made from orange peel waste, capable of detecting harmful chemicals in water.

## Contribution

A sustainable pesticide detection platform using orange peel-derived laser-induced graphene is developed and tested.

## Key findings

- The sensor detects organophosphate pesticides like Malathion and Chlorpyrifos with nanomolar sensitivity.
- The sensor works effectively in complex matrices like tap water.
- Pretreatment with paraffin improves sensor reproducibility and structural integrity.

## Abstract

The growing impacts
of climate change, combined with
the environmental
burden of global pollutants such as agricultural pesticides, have
intensified the demand for sustainable and innovative technologies
for their monitoring and mitigation. In this study, we introduce a
low-cost, easy-to-fabricate, and rapid sensor platform utilizing orange
peel (OP)an abundant agricultural by-productas a sustainable
substrate for the fabrication of laser-induced graphene (LIG). The
sensor was designed to detect organophosphate pesticides, namely Malathion
and Chlorpyrifos, using electrical impedance spectroscopy (EIS) combined
with principal component analysis (PCA) in an electronic tongue sensor
array. To improve the structural integrity and reproducibility of
the developed sensor, the OP was pretreated with paraffin prior to
the laser writing process. Morphological, spectroscopic, and electrical
characterizations confirmed the successful formation of conductive
graphitic structures. LIG-based devices demonstrated linear sensitivity
in the nanomolar range (1 to 20 nmoL–1) and retained
discriminative capability even in complex matrices, such as tap water.
The proposed sensor is simple to fabricate, cost-effective, and enables
in situ production using waste biomaterials, offering an accessible
and environmentally friendly solution for pesticide monitoring.