| Abstract
| - Until now, all methods for temperature sensing in capillary electrophoresis (CE) relied on molecular probes withtemperature-dependent spectral/optical properties. Herewe introduce a nonspectroscopic approach to determiningtemperature in CE. It is based on measuring a temperature-dependent rate constant of complex dissociation bymeans of a kinetic CE method known as nonequilibriumcapillary electrophoresis of equilibrium mixtures (NECEEM). Conceptually, a calibration curve of “the rateconstant versus temperature” is built using NECEEM anda CE instrument with a reliable temperature control or,alternatively, a nonelectrophoretic method, such as surface plasmon resonance. The calibration curve is thenused to find the temperature during CE in the same bufferbut with another CE apparatus or under otherwise different conditions (cooling efficiency, length and diameter ofthe capillary, electrical field, etc.). In this proof-of-principle work, we used the dissociation of a protein−DNA complex to demonstrate that the NECEEM-basedtemperature determination method allows for temperaturedetermination in CE with a precision of 2 °C. Then, weapplied the NECEEM-based temperature determinationmethod to study heat dissipation efficiency in CE instruments with active and passive cooling of the capillary. Thenonspectroscopic nature of the method makes it potentially applicable to nonspectroscopic detection schemes,e.g. electrochemical detection. A “kinetic probe” can becoloaded into the capillary along with a sample for in situtemperature measurements. Higher order chemical reactions can also be used for temperature sensing, provideda kinetic CE method for measuring a corresponding rateconstant is available.
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