Simultaneously performing Taylor dispersion analysis with fluorimetry, photometry, and contactless conductometry at...

Taylor dispersion analysis (TDA) is a rapid and precise method for determining the hydrodynamic radius (R_H) of various substances. We present a versatile TDA system with a flow-through sample injection device, two compact 3-in-1 detectors, and a high-voltage power supply. The 3D-printed detectors combine fluorimetry (FD), photometry (AD@255 nm), and contactless conductometry (C⁴D) in a single head, enabling simultaneous detection at one capillary window. Using bovine serum albumin (BSA) as a model analyte, we compare TDA with different detection methods. BSA labeled with fluorescein isothiocyanate (FITC) is analyzed in both pulse mode and capillary electrophoresis (CE) TDA. FD and AD detection yield similar R_H values, except when FITC binds with small ions in the buffer. In phosphate buffer, C⁴D underestimates R_H values by approximately 18 % due to BSA self-association. In Tris-based buffers, C⁴D values are 87%-96 % of AD values in pulse mode. With CE-TDA using Tris-CHES buffer, no statistical difference is found across all detections. The system is also applied to CE-TDA of various compounds, particularly charged saccharides. CE-TDA improves the accuracy of TDA results from C⁴D. We demonstrate the resolution of mixed C⁴D-TDA signals with assistance from FD and AD signals, successfully resolving gluconate peaks fully covered by another compound. The versatile system with 3-in-1 detection offers a powerful tool for TDA of mixtures and enhances sample throughput.