Engineering:Evaporative light scattering detector (ELSD)

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An evaporative light scattering detector (ELSD) is a detector used in conjunction with high-performance liquid chromatography (HPLC). It is commonly used for analysis of compounds where UV detection might be a restriction and therefore compounds do not efficiently absorb UV radiation, such as sugars, antivirals, antibiotics, lipids, phospholipids, terpenoids, and alcohols.[1][2] ELSDs is related to the charged aerosol detector (CAD) and falls under the category of general-purpose detectors, similar to refractive index detectors (RI).[3]

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, 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 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 photomultiplier tube.[1]BDS

References

  1. 1.0 1.1 "2424 Evaporative Light Scattering Guide". Waters Corporation. https://www.waters.com/webassets/cms/support/docs/71500121802rb.pdf. 
  2. Douville, V.; Lodi, A.; Miller, J.; Nicolas, A.; Clarot, I.; Prilleux, B.; Megoulas, N.; Koupparis, M. (2006-08-01). "Evaporative light scattering detection (ELSD): a tool for improved quality control of drug substances". Pharmeuropa Scientific Notes 2006 (1): 9–15. ISSN 1814-2435. PMID 17694640. 
  3. "Principles and Practical Applications of Shimadzu's ELSD-LT 2 Evaporative Light Scattering Detector". Shimadzu Corporation. http://www.ssi.shimadzu.com/products/literature/lc/c190e108.pdf.