Structure and Composition of Capillary Electrophoresis Apparatus

The capillary electrophoresis instrument is mainly composed of five parts: capillary, sample injection system, high pressure system, detection system and data acquisition system.

high-voltage power supply

(1) Stable and continuously adjustable DC power supply, generally the maximum voltage can reach 30-50kV, and the maximum current is 200-300mA;

(2) With constant voltage, constant current and constant power output;

(3) Electric field intensity program control system;

(4) Voltage stability: 0.1%;

(5) Power polarity is easy to switch;

(6) It has good insulation performance.

capillary

(1) Materials: chemical and electrical inertness, ultraviolet visible light transmittance, flexibility, high strength and low price are required.

Ordinary glass capillary: cheap, but with large electroosmosis and large adsorption.

Quartz glass capillary: commonly used, coated with polyimide. Stable performance, large electroosmosis, but also some adsorption.

PTFE capillary: new material, small electroosmosis, but unstable performance.

(2) Specification: inner diameter 20~200 μ m. Outer diameter 350~400 μ m； Length<=1m;

detector

Requirements: It has extremely high sensitivity and can be detected at the end of the column;

Integration of detector, data acquisition and computer data processing;

Type detection limit/mol

UV visible 10-13~10-15

Fluorescence 10-15 ～ 10-17

Laser induced fluorescence 10-18 ～ 10-20

Conductivity 10-18 ～ 10-19