Microfabricated disposable nanosensor based on CdSe quantum dot/ionic liquid-mediated hollow fiber-pencil graphite electrode for simultaneous electrochemical quantification of uric acid and creatinine in human samples

•Sensor based on modified CdSe quantum dot/ionic liquid mediated hollow fiber graphite electrode.•One-step simultaneous purification, pre-concentration, extraction, back-extraction and determination of electroactive analytes.•Target analyte uric acid (UA) and creatinine (Crn) in urine and serum samples.•Disposable nature of sensor reduced risk of carry-over.

In this research, a novel sensitive electrochemical nanosensor based on the cadmium selenide quantum dots (QDs)/ionic liquid mediated hollow fiber-pencil graphite electrode (HF-PGE) was prepared and applied for simultaneous determination of uric acid (UA) and creatinine (Crn) in urine and serum samples. The electrocatalytic oxidation of the analytes was investigated via differential pulse (DPV) and cyclic voltammetry (CV). The experiments were designed, in two different steps, according to Taguchi's method; OA9 L9 (33) and OA9 L9 (34) orthogonal array to optimize experimental runs. The results revealed that the electrode response was initially influenced by the types of sensor and types of ionic liquids and their ratios. The amount of QD, buffer pH, equilibration time and scan rate also influenced electrode response efficiency. According to the results of Taguchi analysis, the amount of tetra phenyl phosphonium chloride (TPPC) and QD were the most influencing parameters on the yield response of the modified electrodes. Linear ranges were obtained between 0.297-2.970 × 103 and 0.442-8.840 × 103 μM, with the detection limits of 0.083 and 0.229 μM and relative standard deviations (RSD) of 2.4% and 1.8%, for UA and Crn, respectively. Finally, the proposed method was successfully examined for simultaneous determination of UA and Crn in human urine and serum samples.

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