Waters ACQUITY UPLC I-Class, System Manual, Page: 30 / 68

2-6 Optimizing Performance
the intake cycle. Leaks at high pressure fittings (downstream of the i
2
Valves )
can leak solvent but do not introduce air.
To prevent leaks, follow Waters’ recommendations for the proper tightening of
system fittings. Note specifically that different techniques apply to
retightening fittings versus installing them for the first time.
See also:
• The user documentation for the specific system modules for more details
on leak detection.
• The ACQUITY UPLC Column Compartments Operator’s Overview and
Maintenance Information for details on connecting active preheaters.
Sample preparation
UPLC analysis places some additional restrictions on sample preparation.
Particulates
The small column frit size (0.2 μ m) can become blocked more easily than
larger HPLC column frits (2.0
μ
m). Particle-free mobile phase solvents and
sample solutions are therefore essential for UPLC analysis. See “General
guidelines” on page 2-2 for recommendations on choosing and handling
solvents.
Matching sample diluents
When you use the auto-dilution option on the SM-FTN, the purge solvent
serves as the sample diluent. Ensure that your sample solution is soluble and
miscible in your chosen purge solvent.
Caution:
To avoid broad peaks and poor peak shape, ensure that your
sample diluents match the initial conditions of your gradient.