ECL sensor for selective determination of citrate ions as a prostate cancer biomarker using polymer of intrinsic microporosity-1 nanoparticles/nitrogen-doped carbon quantum dots

Urine citrate analysis is relevant in the screening and monitoring of patients with prostate cancer and calcium nephrolithiasis. A sensitive, fast, easy, and low-maintenance electrochemiluminescence (ECL) method with conductivity detection for the analysis of citrate in urine is developed and validated by employing polymer of intrinsic microporosity-1 nanoparticles/nitrogen-doped carbon quantum dots (nano-PIM-1/N-CQDs). Using optimum conditions, the sensor was applied in ECL experiments in the presence of different concentrations of citrate ions. The ECL signals were quenched gradually by the increasing citrate concentration. The linear range of the relationship between the logarithm of the citrate concentration and ΔECL (ECL of blank − ECL of sample) was obtained between 1.0 × 10 ⁻⁷ M and 5.0 × 10 ⁻⁴ M. The limit of detection (LOD) was calculated to be 2.2 × 10 ⁻⁸ M (S/N = 3). The sensor was successfully applied in real samples such as human serum and patient urine. Graphical abstract: [Figure not available: see fulltext.].