Surfactant-Based Polymer Microchip Electrophoresis of Ciprofloxacin Hydrochloride Monohydrate in Unfiltered Milk With Fluorescence Detection

This work describes a cross-shaped PMMA ME system capable of detecting ciprofloxacin hydrochloride monohydrate (CPFH) in unfiltered milk samples. The cross-shaped PMMA ME system utilizes a BGE consisting primarily of the surface-active agent SDS to solubilize milk fat and improve the zeta potential of the PMMA microchannel surface. A theoretical lumped-element circuit model for cross-shaped ME is introduced in this work to calculate the migration time of CPFH. This manuscript improves the capabilities of PMMA-based ME for CPFH in milk using an SDS-based BGE. The presented ME system has a faster migration time, higher mean output voltage, and thinner full-width at half-maximum than previously reported dairy-based biosensor systems. Most notably, the migration time of the new system is under 10 min, being the time associated with the milking of cattle. The system is also found to be able to detect the presence of milk fat. Discussion is included of potential future integration with existing high-sensitivity methodologies to place the overall ME system's limit of detection below an established target. To the authors’ knowledge, this is the first reported account of a PMMA ME system capable of detecting CPFH in unfiltered milk.