A lab on a chip device for the determination of tranexamic acid using a peroxyoxalate chemiluminescence system

Abstract

A highly sensitive, rapid and economical method for the determination of tranexamic acid (TA) in pharmaceutical formulations was developed using a peroxyoxalate chemiluminescence system in a lab-on-a-chip device. Peroxyoxalate chemiluminescence (PO-CL) is an indirect type of CL that allows the detection of native fluorophores or compounds derivatised with fluorescent labels. Here, fluorescamine (FA) was reacted with TA and the derivatisation product (FA-TA) was used in a bis-(2,4,6-trichlorophenyl)oxalate (TCPO)-CL system. The parameters that influenced the CL signal intensity were carefully optimised. These included the pH, the concentration of reagents used, the flow rates and the instrumental setup. Additionally, the effects of imidazole, which is commonly used in the TCPO-CL system as a catalyst, and of various surfactants on the CL signal intensity were also investigated. Under optimised conditions, a calibration curve was obtained with a wide linear range (5–900 ng mL⁻¹). The limit of detection (LOD) was 1 ng mL⁻¹, while the limit of quantification (LOQ) was 3 ng mL⁻¹. The method was rapid; approximately 120 runs could be performed per hour, consuming only 0.3 μg of FA and 2.5 μg of TCPO per run. Finally, the method was applied for the determination of TA in pharmaceutical products and was found to be free of interference from other ingredients that are usually present in these preparations.