# Real-Time Acetone Gas Monitoring Using Calixarene-Functionalized Guided-Mode Resonance-Based Sensors

## TL;DR

This paper introduces a portable optical sensor for detecting acetone gas at room temperature, suitable for workplace safety monitoring.

## Contribution

A novel calixarene-functionalized GMR sensor for real-time acetone detection with low power and high repeatability.

## Key findings

- The sensor detects acetone at 80 ppm with a response following an extended Langmuir isotherm.
- It shows a 4.5% standard deviation in repeat measurements, indicating high reliability.
- The sensor operates at room temperature and is suitable for workplace safety monitoring.

## Abstract

Portable sensors to detect volatile organic compounds
(VOCs) are
needed for many societal and industrial applications, such as diagnosing
patient health through breath analysis or monitoring industrial environments
for worker safety. Acetone, a widely used industrial solvent, is an
important example that requires sensitive detection to prevent hazardous
exposure over workplace safety limits. Established sensor technologies
suffer from drawbacks such as high operating temperatures and power
consumption, long-term drift, or high complexity. Here, we present
an optical gas sensor based on a guided-mode resonance (GMR) that
affords handheld operation and a simple readout. The GMR sensor features
a medium quality (Q-factor) and is functionalized with a calixarene
layer that exhibits a refractive index change upon exposure to acetone.
The sensor achieves a limit of detection (LOD) of 80 ppm for acetone
vapor at room temperature, with a response following an extended Langmuir
isotherm, making it highly suitable for monitoring workplace safety,
where a prolonged exposure to levels >170 ppm is considered dangerous.
We also show that the sensor response is repeatable within a 4.5%
standard deviation across measurements, highlighting that the technology
offers a low-cost, high-performance solution for monitoring workplace
acetone levels.