Detection of bilirubin by stripping voltammetry at the gelled anisole – aqueous electrified interface supported with a 3D printed pore

A method is reported for the detection of bilirubin its anionic form (BIL2−) by stripping voltammetry at the electrified liquid-liquid interface. In this respect, we have used the aqueous || anisole and aqueous || anisole-PVC gel-based interface as an electroanalytical platform to study interfacial ion transfer reactions of model ion (TPrA+) and BIL2−. The gelled organic phase was supported with a 3D printed pore having a few hundred µm in diameter that, upon contact with the aqueous solution, was polarized. Next, cyclic voltammetry and linear sweep voltammetry was used with or without the stripping step to study the electrochemical behavior of TPrA+ and BIL2− at the aqueous || anisole and the aqueous || anisole-PVC gel-based eLLIs. BIL2− detection was studied in spiked artificial and real urine samples given that this analyte should be absent in the healthy patients urine. We have found that anisole is a suitable solvent for organic phase gel preparation, it stabilizes the LLI within the pore and allows the BIL2− detection with a LOD = 2.84 µM and sensitivity (for real and spiked urine sample) of 0.181 nA·µM− 1 (pore Ø = 330 μm). These findings further underline the utility of the sensors based on the ion transfer.