Hoefer DQ300 - Manual (Page 26)

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5. Troubleshooting
Following are troubleshooting tips for problems
the user may encounter.
5.1 Low or No Reading
1. Are all the reagents and standards made to
specification? Are any of the reagents expired?
Is the dilution done correctly?
2. Has the sample been exposed to light for an
extended period?
Some fluorescent dyes are susceptible to photodeg-
radation. It is recommended that the dye solution
be protected from the light.
3. Is the correct optical channel selected for the
application? Has the instrument been calibrated
prior to reading?
4. Is the sample in a detectable, linear range for the
instrument?
Sample concentration might be too low or too high
to be detected (see 4.2 on page 16).
5. Is the right type of cuvette being used?
Methacrylate cuvettes should be used for UV
applications.
6. Does the sample volume meet the minimum
requirement?
The minimum volume is 2 mL for a 10 × 10 mm
cuvette, or 50 µL for a Minicell.
7. Is the a Minicell adaptor inserted in the correct
orientation?
The Minicell adaptor needs to be placed in the
correct position.
If the BLUE channel is selected, insert the Minicell
adaptor in the sample compartment with the tab
away from you and the “BLUE” label facing you.
If the UV channel is selected, insert the Minicell
adaptor in the sample compartment with the tab
nearest to you and the “UV” label facing you.