Waters 2489, Operator'S Manual

Page: 209 / 234

Solvent miscibility D-3
Tetrahydrofuran
When using unstabilized tetrahydrofuran, ensure that your solvent is fresh.
Previously opened bottles of tetrahydrofuran contain peroxide contaminants,
which cause baseline drift.
Solvent miscibility
Before you change solvents, refer to the table below to determine the
miscibility of the solvents to be used. When you change solvents, be aware
that
• changes involving two miscible solvents may be made directly. Changes
involving two solvents that are not totally miscible (for example, from
chloroform to water), require an intermediate solvent (such as
isopropanol).
• temperature affects solvent miscibility. If you are running a
high-temperature application, consider the effect of the higher
temperature on solvent solubility.
• buffers dissolved in water can precipitate when mixed with organic
solvents.
When you switch from a strong buffer to an organic solvent, flush the buffer
out of the system with distilled water before you add the organic solvent.
Warning: Tetrahydrofuran contaminants (peroxides) are potentially
explosive if concentrated or taken to dryness.
Solvent miscibility
Polarity
Index
Solvent
Viscosity
CP, 20 °C
Boiling
Point °C
(1 atm) Miscibility
Number
(M)
λ
Cutoff
(nm)
–0.3 N-decane 0.92 174.1 29 ––
–0.4 Iso-octane 0.50 99.2 29 210
0.0 N-hexane 0.313 68.7 29 ––
0.0 Cyclohexane 0.98 80.7 28 210
1.7 Butyl ether 0.70 142.2 26 ––
1.8 Triethylamine 0.38 89.5 26 ––