Electrochemical and HPLC-based detection of furosemide using Fe-Co LDH@ZIF-8 magnetic MWCNT-modified SPCE

This study demonstrates the application of both electrochemical and HPLC techniques for the identification of furosemide (FSD) in blood and saliva specimens. A nanocomposite comprising cobalt–iron layered double hydroxide (LDH), ZIF, and magnetic multiwalled carbon nanotubes (mMWCNTs) was incorporated onto a screen-printed carbon electrode (SPCE). FTIR, XRD, and FESEM were employed to elucidate the formation and structure of the nanocomposite. Cyclic voltammetry (CV) revealed that the modified electrode (Fe–Co LDH@ZIF-8@mMWCNT/SPCE) exhibited significantly enhanced peak current responsiveness and superior electron transfer compared to the unmodified SPCE owing to the synergistic effect of the modifiers. The suggested sensor is capable of detecting FSD at exceptionally low concentrations of 3.0 μM, which is 2–5 times lower than the detection range of comparable electrochemical sensors, typically ranging from 6–15 μM. This sensor delivers robust performance using comparatively straightforward nanocomposite assembly, offering practicality for real-sample analysis with sensitivity of 4.04 µA·µM⁻¹. The recovery rates for counterfeit biological samples ranged from 90.6 % to 94.6 %, indicating that the results are accurate and reliable. The findings indicate that the proposed nano-modification technology addresses the sensitivity challenges associated with conventional SPCE-based sensors, enabling the detection of FSD in clinical samples.