The working principle of a pre concentrator is mainly to separate and concentrate the liquid part of the sample in order to increase the concentration of the target substance in the sample. It is commonly used in fields such as biological sample analysis, chemical analysis, and environmental monitoring. Its working principle generally includes the following steps:
Sample introduction: The pre concentrator introduces the test sample into the concentration device through the injection system. These samples may be liquids or gases containing dissolved substances.
Preprocessing or Separation: The sample is processed by physical or chemical methods to remove irrelevant substances or enable the target substance to be concentrated. Common separation methods include:
Membrane filtration: Use semi permeable membrane filtration to remove large molecular impurities or solvents.
Gas phase separation: For gas samples, the target substance is separated from the gas through condensation or adsorption techniques.
Solvent extraction: By selectively dissolving the target substance, other unwanted components are removed.
Concentration process: Concentrate the target substance in the remaining liquid by removing solvents or volatile components. This process may adopt:
Evaporation: Concentrate the target substance by evaporating the solvent through heating or depressurization.
Condensation: By cooling a gas or vapor sample, the solvent in it condenses into a liquid, leaving behind a concentrated target substance.
Adsorption/desorption: Use adsorbent materials (such as activated carbon, silica gel, etc.) to adsorb solutes, and then release them through the desorption process to achieve concentration.
Concentrated sample: When the concentration of the target substance reaches the preset standard, the sample is introduced into the analysis system for subsequent analysis, such as chromatographic analysis, mass spectrometry analysis, etc.
Detection and control: Pre concentration equipment is generally equipped with a monitoring system to real-time control parameters such as temperature, pressure, and flow rate during the concentration process, ensuring stable and uniform concentration effect.
Through these steps, the pre concentrator can effectively increase the concentration of the target substance in the sample, facilitating subsequent precise analysis.