Molecularly imprinted electrochemical detection of inositol trispyrophosphate in sweat as an emerging oxygen-transfer doping agent.

چکیده اصلی

BACKGROUND: Inositol trispyrophosphate (ITPP) is a highly polar, polyphosphorylated hemoglobin allosteric effector with potential misuse risk for enhancing oxygen delivery. Existing ITPP assays rely mainly on laboratory chromatographic-mass spectrometric platforms using urine or plasma-related matrices, which are powerful for confirmatory analysis but less suited to rapid, non-invasive, front-end screening. Sweat offers an attractive sampling matrix for sport-related monitoring, yet ITPP is electrochemically inactive and difficult to recognize selectively in this complex matrix. A rapid sweat-compatible sensing strategy for preliminary ITPP screening is therefore needed. RESULTS: We developed a molecularly imprinted electrochemical sensor in which pyrrole was electropolymerized in the presence of ITPP to generate recognition cavities in a polypyrrole film on a glassy carbon electrode. After template removal, ITPP rebinding hindered ferricyanide redox-probe transport, producing a concentration-dependent DPV current decrease. FT-IR spectroscopy, hydrogen-bond competition experiments, adsorption thermodynamics, and DFT calculations supported a recognition mechanism governed by multivalent hydrogen bonding and electrostatic complementarity between phosphate groups and oxidized polypyrrole NH+ sites. The sensor quantified ITPP over 50.0-1500 ng/mL, with a calculated LOD of 11.3 ng/mL and LOQ of 34.2 ng/mL. It retained performance across sweat-relevant pH 5.0-7.0, showed limited responses to structural analogs and sweat-relevant interferents, and achieved 94.3-104% recovery with RSDs below 5% in spiked artificial and authentic sweat samples. SIGNIFICANCE: This work establishes a proof-of-concept MIP-EC platform for rapid, non-invasive preliminary screening of ITPP in sweat. Rather than replacing confirmatory LC-MS/MS or LC-HRMS analysis, the sensor provides a complementary front-end strategy for highly polar, electrochemically inactive targets and a mechanistically supported framework for future sweat-compatible anti-doping screening devices and related biofluid applications.

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