A high performance system to study the influence of temperature in on-line solid-phase extraction capillary electrophoresis.
A novel high performance system to control the temperature of the microcartridge in on-line solid phase extraction capillary electrophoresis (SPE-CE) is introduced. The mini-device consists in a thermostatic bath that fits inside of the cassette of any commercial CE instrument, while its temperature is controlled from an external circuit of liquid connecting three different water baths. The circuits are controlled from a switchboard connected to an array of electrovalves that allow to rapidly alternate the water circulation through the mini-thermostatic-bath between temperatures from 5 to 90 °C. The combination of the mini-device and the forced-air thermostatization system of the commercial CE instrument allows to optimize independently the temperature of the sample loading, the clean-up, the analyte elution and the electrophoretic separation steps. The system is used to study the effect of temperature on the C18-SPE-CE analysis of the opioid peptides, Dynorphin A (Dyn A), Endomorphin1 (END) and Met-enkephalin (MET), in both standard solutions and in spiked plasma samples. Extraction recoveries demonstrated to depend, with a non-monotonous trend, on the microcartridge temperature during the sample loading and became maximum at 60 °C. Results prove the potential of temperature control to further enhance sensitivity in SPE-CE when analytes are thermally stable.
Laboratorio de Investigación y Desarrollo de Métodos Analíticos (LIDMA), Universidad Nacional de La Plata, Calle 47 y 115 (1900), La Plata. Buenos Aires, Argentina.
Marcos
M
Tascon
Departamento de Química Analítica, Universidad de Barcelona, Av. Diagonal 645, Barcelona, España.
Fernando
F
Benavente
Departamento de Química Analítica, Universidad de Barcelona, Av. Diagonal 645, Barcelona, España.
Victoria
V
Sanz-Nebot
Laboratorio de Investigación y Desarrollo de Métodos Analíticos (LIDMA), Universidad Nacional de La Plata, Calle 47 y 115 (1900), La Plata. Buenos Aires, Argentina; Centro de Investigación y Desarrollo en Tecnología de Pinturas (CIDEPINT-CIC-CONICET), Av. 52 y 120 (1900), La Plata, Buenos Aires, Argentina. Electronic address: leogagliardi@quimica.unlp.edu.ar.
Leonardo G
LG
Gagliardi
Capillary electrophoresis; On-line pre-concentration; Opioid peptides; Solid-Phase extraction; Temperature