Solvent viscosity C-7
Solvent viscosity
Generally, viscosity is not important when you are operating with a single
solvent or under low pressure. However, when you are running a gradient, the
viscosity changes that occur as the solvents are mixed in different proportions
can result in pressure changes during the run. For example, a 1:1 mixture of
water and methanol produces twice the pressure of either water or methanol
alone.
If the extent to which the pressure changes will affect the analysis is not
known, monitor the pressure during the run using the Chart Out terminal.
Mobile phase solvent degassing
Mobile phase difficulties account for 70% or more of all liquid
chromatographic problems. Using degassed solvents is important, especially
at wavelengths below 220 nm.
Degassing provides
• stable baselines and enhanced sensitivity.
• reproducible retention times for eluting peaks.
• reproducible injection volumes for quantitation.
• stable pump operation.
Gas solubility
Only a finite amount of gas can be dissolved in a given volume of liquid. This
amount depends on
1/8-inch tubing 1/2-inch
Minimum bend radius for stainless steel tubing (Continued)
Tubing size (OD) Minimum bend radius
R
To Next Page
Loading...
