A Mobile Analytical Chemistry Workstation with a C4D Sensor for Rapid Detection of Organophosphates Under Field Conditions

The mobile workstation integrates capillary electrophoresis with C4D on disposable PDMS chips, enabling rapid, sensitive organophosphate detection in the field. Optimised injection techniques, voltage settings, and a custom adaptor ensure reproducible separations and robust performance under challenging field conditions. The portable system reduces analytical turnaround times relative to laboratory methods, enabling rapid decisions in forensic and environmental scenarios. Its cost-effective, user-friendly design supports widespread on-site deployment, boosting emergency response and public safety. Highlights: Timely detection of organophosphates in outdoor environments remains a critical challenge for forensic and environmental monitoring. Traditional methods often require transporting samples to centralised laboratories, delaying essential response actions. In this study, we present a novel mobile analytical chemistry workstation that integrates capillary electrophoresis (CE) with capacitively coupled contactless conductivity detection (C4D) on low-cost polydimethylsiloxane (PDMS) microfluidic chips, enabling rapid and accurate on-site analysis of organophosphates. The system features a streamlined workflow that includes in-field sample collection, microfluidic analysis, and the wireless transmission of data to a central command centre for immediate decision-making. The detection system demonstrates a linear range of 2.5 mM to 20 mM for dimethyl methylphosphonate (DMMP), with an estimated limit of detection (LOD) of 2.5 mM. We evaluate the feasibility of combining CE and C4D under field conditions, highlighting both the strengths and limitations of this integrated platform.