# Albendazole Detection at a Nanomolar Level Through a Fabry–Pérot Interferometer Realized via Molecularly Imprinted Polymers

## TL;DR

A new sensor using molecularly imprinted polymers detects albendazole at very low levels, offering a fast and selective method for monitoring this drug in food and the environment.

## Contribution

A novel Fabry–Pérot interferometer sensor with a MIP layer achieves nanomolar-level detection of albendazole with high selectivity and low cost.

## Key findings

- The sensor achieved a detection limit of 27 nM for albendazole.
- It showed a linear response between 27 nM and 100 nM concentrations.
- The sensor demonstrated good recovery in pharmaceutical samples.

## Abstract

Albendazole (ABZ) is a broad-spectrum anthelmintic drug whose residual presence in food and the environment raises public health concerns, requiring rapid and sensitive methods of detection. In this work, a sensitive Fabry–Pérot interferometer (FPI) probe was fabricated by realizing a cavity located at the tip of a single-mode optical fiber core with a molecularly imprinted polymer (MIP) for ABZ detection. The fabrication process involved the development of a photoresist-based micro-hole filled by the specific MIP via thermal polymerization. Interferometric measurements obtained using the proposed sensor system have demonstrated a limit of detection (LOD) of 27 nM, a dynamic concentration range spanning from 27 nM (LOD) to 250 nM, and a linear response at the nanomolar level (27 nM–100 nM). The selectivity test demonstrated no signal when interfering molecules were present, and the application of the sensor for ABZ quantification in a commercial pharmaceutical sample provided good recovery, in accordance with bioanalytical validation standard methods. These results demonstrate the capability of a MIP layer-based FPI probe to provide low-cost and selective optical-sensing strategies, proposing a competitive approach to traditional analytical techniques for ABZ monitoring.