Biotage ELSD-1080, Operation Manual

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Biotage ELSD-1080
3.2 Operational Parameters
The Biotage ELSD-1080 detector responds to all compounds
that are less volatile than the mobile phase and is independent
of a compound’s optical properties. It therefore provides
advantages over other spectroscopic detectors for detecting
compounds that are deficient in a UV chromophore or
fluorophore.
The removal of aqueous mobile phase within an ELSD is
typically achieved by setting the evaporator temperature to the
eluent’s boiling point (e.g. 100 °C) in order to remove the
solvent. For non-volatile compounds, operating at these high
temperatures maximizes the signal response.
However, at these temperatures volatile and semi-volatile
compounds are destroyed and are therefore not detected. This
is problematic for small molecules, such as pharmaceuticals and
drug candidates.
The ELSD-1080 is specifically designed to evaporate difficult
solvents at ambient and sub-temperatures in order to maximize
detection of semi-volatile compounds.
The ELSD-1080 has patented technology that reduces the
evaporation time of highly aqueous solvents at low
temperature, and also prevents the evaporation tube becoming
saturated, which would otherwise preventing further
evaporation occurring.
Using this patented evaporation gas technology, a 20 µm
droplet of water at 30 °C can be dried
ca .3x faster than just
temperature alone. Using the ELSD-1080, water can be
evaporated as low as 20 °C, providing maximum sensitivity to
thermally sensitive compounds. For maximum sensitivity of
non-volatile compounds the evaporation gas can be turned off
at higher evaporation temperatures.
Therefore, unlike other ELSD-1080s, where the evaporator
temperature is set according to the type of mobile phase, the
Biotage ELSD-1080 evaporator temperature is independent of
the mobile phase. Consequently, the ELSD-1080 can be set at
30 °C for all types of mobile phase provided the evaporator gas
flow is adjusted accordingly. This method of operation ensures
that the ELSD sensitivity is maximized even for low molecular
weight compounds.
3.3 Detector Controls
The Biotage ELSD-1080 detector can be used as a standalone
detector via the front keypad and screen, as shown in Figure 5.
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