A tunable analytical platform for bile acid isomers: from molecular recognition to pharmaceutical quality control

This study presents an innovative Trapped Ion Mobility Spectrometry-Mass Spectrometry (TIMS-MS) approach employing rifampicin (RFP) and Ba²⁺ coordination chemistry to address the analytical challenges posed by structurally similar bile acid (BA) isomers. Our methodology facilitates the formation of distinctive ternary complexes that enable effective isomer separation, achieving separation resolution (R_p-p) values reached to 2.77. Otherwise, theoretical calculation modeling revealed that the differential binding interactions between RFP/Ba²⁺ and various BA isomers underlie the separation mechanism, with theoretical predictions showing remarkable consistency with experimental results (≤ 3.0% error). The technique demonstrates outstanding quantitative reliability (R² > 0.99) and has been successfully implemented in both pharmaceutical formulation analysis and serum sample testing. Characterized by its operational simplicity, rapid analysis time, and high sensitivity, this robust analytical platform offers significant potential for advancing BA research in pharmaceutical quality control, clinical diagnostics, and regulatory compliance applications.