Publication

Abstract : Accurate determination of magnesium ions in the blood is crucial due to their association with various disease conditions, including osteoporosis, nerve disorders, cardiovascular issues, and impaired kidney function. In this work, we developed a carbon quantum dot (CQDs) based fluorometric paper analytical device (PAD) for detecting magnesium ions in human blood serum. The fluorescent CQDs were synthesized using a simple microwave-assisted method. The addition of 8-hydroxyquinoline quenches the fluorescence of the CQDs, which is regained in the presence of magnesium ions. This OFF-ON mechanism was utilized for the sensitive and selective detection of magnesium ions on the PAD. In order to deploy the PAD for testing human blood samples, a calibration plot was generated from the fluorescent intensity obtained using serum samples spiked with magnesium ions. It exhibited two linear ranges of detection with a detection limit of 3.9 µM and a limit of quantification of 13 µM. The PAD showed sensitivities of 25.93 a.u/mM and 48.52 a.u/mM for the magnesium concentration ranges from 0.76 – 1.26 mM and 1.76 – 10.76 mM, respectively. The PAD was tested and validated using volunteer blood serum samples, showing good accuracy with a relative error of <5 % from the clinical lab results. This innovative CQDs-based PAD presents a promising and practical tool for reliable and efficient magnesium ion detection in human serum, offering potential applications in healthcare and clinical diagnostics.