Capillary electrophoresis with capacitively coupled contactless conductivity detection (C 4 D) for rapid and simple determination of lactate in sweat.

An analytical method based on capillary electrophoresis (CE) using capacitively coupled contactless conductivity detection (C 4 D) was developed and validated for fast, straightforward, and reliable determination of lactate in artificial and human sweat samples. The background electrolyte was composed of equimolar concentrations (10 mmol/L) of 2-(N-morpholino)ethanesulfonic acid and histidine, with 0.2 mmol/L of cetyltrimethylammonium bromide as electroosmotic flow inverter. The limit of detection and quantification were 3.1 and 10.3 µmol/L, respectively. Recoveries in the 97 to 118% range were obtained using sweat samples spiked with lactate at three concentration levels, indicating an acceptable accuracy. The intraday and interday precisions were 1.49 and 7.08%, respectively. The proposed CE-C 4 D method can be a starting point for monitoring lactate concentrations in sweat samples for diagnostics, physiological studies, and sports performance assessment applications.