Evaporative light detector(Evaporative Light-Scattering Detector，ELSD) It is a commonly used universal detector that can detect organic substances without UV absorption.

　　Evaporative light detectorThe detection process can be divided into three key steps:

Atomization: The liquid sample flowing out of the chromatographic column enters the atomizer of ELSD and forms tiny droplets under the action of high-speed gas flow (usually inert gas, such as nitrogen), forming aerosols.

Evaporation: Aerosols enter a high-temperature drift tube (temperature controlled, usually 50-100 ℃), and the solvent in the droplet rapidly evaporates, leaving only sample particles.

Light scattering detection: Sample particles generate light scattering when passing through a beam of light (such as a laser or LED light source), and the intensity of the scattered light is proportional to the concentration of the sample. It is collected and converted into an electrical signal by a photoelectric sensor, and finally outputs a chromatogram.

Technical characteristics:

Universality: ELSD does not rely on the optical properties of the sample (such as UV absorption or fluorescence), but achieves detection through physical particle size changes, making it suitable for the analysis of most organic, inorganic compounds and polymers, especially for substances without UV absorption, fluorescence or electroactivity.

High sensitivity: By accurately controlling air pressure and temperature, a narrow droplet size distribution is formed in the atomization chamber, greatly reducing the temperature required for droplet evaporation and thus improving detection sensitivity.

Robustness: It can eliminate baseline drift caused by solvent interference and temperature changes, and is suitable for stable detection under gradient elution conditions.

Easy to maintain: Designed with no consumables, the annual maintenance cost is reduced by 76% compared to mass spectrometry, but the atomizer needs to be cleaned regularly to maintain performance.