June 11, 2015, 715004754 Rev. A
Page 57
4 Preparing Solvents
Proper solvent selection and preparation are critical in differential refractometry,
to prevent an erratic baseline or effects such as drift and noise.
4.1 Common solvent problems
The 2414 RI detector measures changes in the refractive index (RI) of the solution
flowing through the sample side of the flow cell. However, factors other than the
presence of dissolved sample molecules can affect a solution’s RI. Common problems
include these conditions:
• Changes in temperature
•Changes in pressure
•Contaminants
• Separation of mixed solvents
• Outgassing of dissolved gases
4.2 Selecting a solvent
An ideal solvent for your analysis has these characteristics:
• Good solubility characteristics for your application
• Significantly different RI than that of the sample components
• Satisfactory baseline noise performance
• Optimum optical sensitivity characteristics
Warning: To avoid the harmful effects of personal contact
with solvents, including inhalation, always wear
chemical-resistant, powder-free gloves and observe good
laboratory practice when you handle them. See the Material
Safety Data sheets for the solvents you use.
Warning: To avoid the harmful effects of personal contact
with leaking solvents, flush the detector with an appropriate
miscible solvent prior to installing or replacing fittings.
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