# Colorimetric Determination of Peroxides: A New Paper-Based Sensor for Detecting Hexamethylene Triperoxide Diamine (HMTD)

## TL;DR

A new paper-based sensor has been developed to quickly and inexpensively detect the explosive HMTD without cross-reacting with other explosives.

## Contribution

A novel, selective, and sensitive paper-based colorimetric sensor for HMTD detection is introduced.

## Key findings

- The sensor detects HMTD at concentrations as low as 0.01 mg/mL.
- The sensor does not cross-react with other explosives like TATP.
- HSV analysis using the Trigit app confirmed the sensor's colorimetric response.

## Abstract

Homemade explosives (HMEs) are of increasing interest to security forces worldwide due to their widespread utilization by terrorists. Their synthesis is relatively straightforward, requiring only a few readily available chemical compounds. Among the most popular HMEs are organic peroxides, specifically triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD). This manuscript reports on a paper-based sensor developed for the detection of HMTD. The sensor facilitates fast, inexpensive, and simple detection of this peroxide. The developed sensor was compared with well-established commercial and in-house-developed iodometric tests typically used for peroxide determination. The colorimetric principle was based on the use of a potassium iodide and citric acid solution applied to a paper substrate. The HMTD and TATP samples were prepared in an acetone–water mixture (1:1, v/v). The sensor was able to detect HMTD down to a limit of 0.01 mg/mL. The developed sensor does not exhibit cross-reactivity with other explosives, including TATP. Furthermore, an HSV analysis of the photographs was performed using the Trigit application.