| How the Agilent 1200 Series Evaporative Light Scattering Detector works |
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Step 1. Eluent is nebulized and small droplets are selected to minimize background noise.
The nebulizer transforms the eluent from the HPLC column into a fine vapor of droplets. The technology in the Agilent 1200 Series ELSD provides for the selection of droplets as a function of their size, preventing larger droplets from entering the evaporation or drift tube. Large droplets cause increased background noise because they are more difficult to evaporate. This selection of droplets makes detection at low evaporation temperatures possible, resulting in low baseline noise and excellent sensitivity, even for semi-volatile solutes.
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Step 2. Small droplets are evaporated at low temperatures to avoid loss of compounds.
Solute molecules are obtained from the vapor using low temperature technology in the heated evaporation or drift tube. The Agilent 1200 Series ELSD is designed to evaporate high boiling mobile phases, such as those with high aqueous concentrations, at very low temperatures. The low temperatures used in the standard operating mode minimize the potential of thermal decomposition of the compound of interest, and makes the Agilent 1200 Series ELSD a more reliable way to detect everything in the sample.
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Step 3. The solute particles are focussed, using gas-supported focusing (GSF) for enhanced signal-to-noise ratios and less maintenance, and detect the light scattering
Assisted by gas-supported focusing, the solute molecules from the vapor pass through an optical head that is designed to measure light scattering. Gas-supported focusing involves the addition of gas to focus the solute particles within the optical head for enhanced detection. The gas surrounding the solute particles also protects the optical head from contamination. The magnitude of the resulting scattered light is related to the concentration of the compounds in the sample.
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