Thermo Scientific Corona Veo, Руководство по эксплуатации

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6 • Operation
Charged Aerosol Detectors Corona Veo (RS) Operating Manual Page 125
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Choose solvents that are specified to have low residue after
evaporation.
For example, LC/MS-grade solvents typically have a lower residue
after evaporation specification than HPLC-grade solvents and are
often the better choice to achieve consistently low baseline noise.
TIP
Many organic solvents have low viscosity, low surface tension
and high volatility, which lead to a high mass transport efficiency
within the detector. For such solvents, it is especially recommended
to select a grade with lowest residue after evaporation.
•
If a particular solvent causes high background current or noise, try a
different grade or vendor.
•
Most HPLC-grade or better solvents are pre-filtered and additional
filtration may increase the concentration of impurities within the
mobile phase. It is therefore recommended to only filter the
aqueous buffer salt portion of a mobile phase.
TIP With solvent gradients, non-volatile impurities in the weaker
solvent (for example, water in reversed-phase) can be concentrated
on the column and elute later to produce large peaks or baseline
artifacts.
•
With highly combustible mobile phases, such as tetrahydrofuran
(THF) and other ethers and ketones, use only nitrogen as supply gas.
•
When changing the operating mobile phase
Make sure that the solvents are miscible and will not cause
precipitation of buffer salts. If required, use an appropriate
intermediate solvent, if required.
TIP Keep this in mind particularly when switching between
chromatographic methods.
•
The stability of water or highly aqueous (< 5% organic modifier)
mobile phase is highly susceptible to microbial growth. Prepare such
mobile phases freshly on a daily basis
•
Select an optimal evaporation temperature to selectively evaporate
background components of the mobile phase. Observe the
guidelines in the
Evaporation Temperature
section.