SEDERE is the leading manufacturer of low-temperature evaporative light scattering detectors (LT-ELSD) for HPLC, micro-HPLC and SFC.

Evaporative light scattering detection provides universal detection for HPLC,it is not dependant on the presence of chromophoric groups on the compound, and is therefore an extremely useful technique when the nature of the compound in the sample is not well understood. Typical applications include proteomics, combinatorial chemistry, lipids, surfactants, high-throughput screening and small molecules. SEDERE LT-ELSDs are commonly used in industrial, governmental and university research laboratories.

The eluent from the HPLC column is transformed into a fine mist of droplets, using the nebulizer. The SEDEX LT technology allows the selection of droplets as a function of their size in order to prevent larger droplets from entering the evaporation (drift) tube. (Large droplets are responsible for increased background noise, as large particles are more difficult to evaporate.)

Solute molecules are obtained from the mist using a heated evaporation (drift) tube, at a low temperature. All SEDEX detectors are designed to evaporate high boiling mobile phases at very low temperatures. This unique feature minimizes the potential for thermal decomposition of the compound of interest, and makes the SEDEX method a more reliable way to detect everything in the sample.

The solute molecules from the mist, assisted by gas supported focusing (GSF), pass through an optical head designed to measure light scattering. Gas supported focusing (GSF) involves the addition of gas to focus the solute particles within the optical head for enhanced detection.

All SEDERE detectors feature low temperature operation to ensure that the superb sensitivity is provided even for semi-volatile compounds. These detectors can be used with micro-HPLC, conventional HPLC and preparative HPLC as well as for combinatorial chemistry.

The unique design of SEDEX LT-ELSD Nebulization cell allows the selection of the droplets as a function of the size. Large droplets, which are the more difficult to evaporate, are responsible for increased noise level. In te glass nebulization cell, the largest droplest are simply eliminated, so that the temperature can be lowered, without compromising the sensitivity (signal to noise ratio)

This diagram illustrates the selection of the droplets as a function of the size. The mist of droplets is created by the nebulizer, and is composed of various sizes droplets. The nebulization cell acts as a real size exclusion selector, so that the droplets of largest dimensions (in blue color) are eliminated. Only droplets which are below a certain limit in size are allowed to flow througth the drift tube.

Most of our competitor's Evaporative light scattering detectors are not able to select droplets, so that the need is to use an higher temperature to reach acceptable levels of noise during the analysis. Selection of the droplets is a unique feature of SEDEX LT-ELSD and provides you the real Low temperature evaporation, and the best sensitivity for all compounds, even semi-volatile ones.