Thermo Scientific Dionex UltiMate 3000 Series Operating Instructions Manual page 85

5.5.1.3 Mobile Phase Delivery System
The pumping system should deliver continuous flow while ensuring intermixing of the mobile
phase (if gradient elution is used). Fluctuations in pump backpressure can cause baseline
noise. If the noise is synchronized with the pump stroke, check your HPLC pump.
The plastics present in some solvent delivery systems are not fully compatible with the
solvents commonly used in chromatography. Therefore, plastic components may dissolve,
and thus impair UV detection.
For UV operation, these guidelines are recommended:
• The mobile phase reservoir should be glass.
• All tubing connections should be made of materials suitable for HPLC applications (for
example, PTFE, ETFE, PEEK, stainless steel, or titanium), as required for the operating
pressures and application.
• Some pump seals incorporate a band spring to preload the seal during the vacuum stroke
of the piston. The band spring should be stainless steel, a fluoropolymer
(perfluoroelastomer or fluorosilicone), or other material of known quality.
5.5.1.4 Flow Cell
To ensure optimum performance of the flow cells, observe the following guidelines:
• All parts of the flow cell that are exposed to solvents are made of fused silica, PEEK
(polyetheretherketone), stainless steel, or PTFE (polytetrafluorethylene). The chemical
resistance of a flow cell depends on the solvents used for the analysis. This applies
particularly to strongly acid solvents with high buffer concentrations and certain solvents,
such as THF (tetrahydrofuran) and CHCl
• When the detector is fitted with a PEEK flow cell, Thermo Fisher Scientific advises
against operating the detector for longer periods (5 minutes or longer) without flow while
a lamp is on. The heat from the lamp may damage the flow cell.
• For information about how to clean a flow cell, see page 125.
5.5.1.5 Lamps
To achieve optimum results, allow 60 minutes for the lamps to stabilize before beginning
operation.
Operating Instructions
VWD-3100 and VWD-3400RS Variable Wavelength Detectors
(dichloromethane).
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UltiMate 3000 Series:
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