An evaporative light scattering detector (ELSD) is a detector used in conjunction with

high-performance liquid chromatography High-performance liquid chromatography (HPLC), formerly referred to as high-pressure liquid chromatography, is a technique in analytical chemistry used to separate, identify, and quantify each component in a mixture. It relies on pumps to pa ...

(HPLC),

Ultra high-performance liquid chromatography adopted by British military intelligence in June 1941 for wartime signals intelligence obtained by breaking high-level encrypted enemy radio and teleprinter communications at the Government Code and Cypher School (GC&CS) at Bletchley Park. ' ...

(UHPLC),

Purification liquid chromatography Purification is the process of rendering something pure, i.e. clean of foreign elements and/or pollution, and may refer to: Religion * Ritual purification, the religious activity to remove uncleanliness * Purification after death * Purification ...

such as flash or preparative chromatography, countercurrent or

centrifugal partition Centrifugal (a key concept in rotating systems) may refer to: *Centrifugal casting (industrial), Centrifugal casting (silversmithing), and Spin casting (centrifugal rubber mold casting), forms of centrifigual casting *Centrifugal clutch *Centrifug ...

chromatographies and

Supercritical Fluid chromatography Supercritical fluid chromatography (SFC) is a form of normal phase chromatography that uses a supercritical fluid such as carbon dioxide as the mobile phase. It is used for the analysis and purification of low to moderate molecular weight, thermal ...

(SFC). It is commonly used for analysis of compounds where UV detection might be a restriction and therefore used where compounds do not efficiently absorb UV radiation, such as sugars, antivirals, antibiotics, fatty acids, lipids, oils, phospholipids, polymers, surfactants, terpenoids and triglycerides. ELSDs is related to the charged aerosol detector (CAD) and like the CAD, falls under the category of destructive detectors. An evaporative light scattering detector (ELSD) is able to detect all compound which are less volatile than the mobile phase, i.e. non volatile and semi-volatile compounds.

Principles of operation

ELSDs analyze solvent after elution from HPLC. As the eluent passes from an HPLC, it is mixed with an inert carrier gas and forced through a

nebulizer In medicine, a nebulizer (American English) or nebuliser (British English) is a drug delivery device used to administer medication in the form of a mist inhaled into the lungs. Nebulizers are commonly used for the treatment of asthma, cystic fibro ...

, which separates the liquid into minute aerosolized droplets. These droplets then pass into a heated drift tube, where the mobile phase solvent is evaporated off. As the

mobile phase In analytical and organic chemistry, elution is the process of extracting one material from another by washing with a solvent; as in washing of loaded ion-exchange resins to remove captured ions. In a liquid chromatography experiment, for exa ...

evaporates, the droplets become smaller and smaller until all that is left is minute particles of dried analyte. These particles are pushed through the drift tube by the carrier gas to the detection region. In this region, a beam of light crosses the column of analyte and the scattering of light is measured by a photodiode or photomultiplier tube. The detector's output is non-linear across more than one order of magnitude and proper calibration is required for quantitative analysis.

References

Measuring instruments {{chromatography-stub