Waters 2998, Overview And Maintenance Manual

Page: 42 / 94

December 5, 2017, 715004753 Rev. B
Page 42
• Instrument verification and qualification
• Benchtop spectrophotometer procedures
The detector uses a standard, 10-mm path length, spectrophotometric cell (quartz cuvette). You
insert the cuvette, with a frosted side facing, up in the cuvette holder, which you then place in the
flow cell assembly.
Figure 2–12: Cuvette holder, with the cuvette inserted
Restriction:
Because the measurement is actually a composite of both the contents of the cuvette
and the flow cell, you must perform cuvette measurements under identical flow cell conditions. If
you store spectra and acquire new spectra for subtraction, note differences, if any, in flow cell
conditions.
Ideally, you perform both the zero and sample measurements using the cuvette when the HPLC
instruments are in the idle or static state and operating under identical flow cell conditions.
2.9.1 Before you begin
Recommendation:
To ensure accurate results, for the zero and sample measurements, use a
matched pair of quartz cuvettes (10-mm path length) from the same manufacturing lot.
Before beginning a measurement using the cuvette:
1. Fill the flow cell by flushing it with 10 mL of the solvent that you will use for the cuvette
measurement procedure.
2. Wipe the clear portion of the cuvette with low-lint, nonabrasive tissue wipes.
2.9.2 Cuvette measurement procedure
To begin a cuvette measurement:
1. Open the door of the detector.
2. To remove the cuvette holder, slide it toward you.
Notice:
Handle the cuvette gently by the frosted sides only. Fingerprints on the clear quartz
interfere with the light path, compromising the integrity of cuvette measuring operations.
Frosted sides of cuvette facing
up and down