Thermo Scientific 074114, Руководство оператора

Страница: 34 / 148

Dionex PDA Operator’s Manual
26
Doc. 065378-01 1/12
2.6.2 Solvent Delivery System
•
The pumping system should deliver continuous flow while
maintaining a consistent mobile phase composition (if gradient
elution is used). Fluctuations in system backpressure may cause
baseline disruptions. High sensitivity applications require a smooth,
low-pulsation pump pressure output. To ensure optimal results,
follow the maintenance schedule recommended in the pump user’s
manual.
•
All materials in the solvent delivery system must be fully compatible
with the mobile phases required for the analysis. For example, IC and
BioLC analyses frequently use mobile phases with extreme pH levels
or high salt concentrations. A PEEK pumping system and PEEK flow
cell are required when running these mobile phases because the
presence of stainless steel in the flow path would contaminate the
system.
•
Reversed-phase solvents (methanol, moderate concentrations of
acetonitrile, etc.) are acceptable for a PEEK system. Other solvents
(and high concentrations of acetonitrile) require a stainless steel
system.
•
All tubing connections should be PTFE (polytetrafluoroethylene),
Tefzel
®
, PEEK, stainless steel, or titanium as required for the specific
operating pressures and application.
•
All mobile phase reservoirs should be compatible with the solvents
used with your application. Some plasticizers in blow-molded
components leach and are strong UV absorbers.
•
Cleanliness is very important. After operating in detection modes that
do not require optically clean reagents (such as conductivity), the
solvent delivery system may need to be thoroughly cleaned. A basic
cleaning procedure is described below; for additional information,
refer to the pump user’s manual.
To avoid contamination, always wear latex gloves that are lint-free,
particle-free, and oil-free when handling pump components in the flow
path. Contamination may cause baseline disruptions, spurious peaks,
and inconsistent results, especially in sensitive applications.