Section 3
Page 53
UVTOCReagents and Standards.fm Storage and Handling Tips
Adjust the following as necessary:
1. Interval, duration, and day of cleaning action. Refer to section 5.2.3.1 on
page 70.
2. Perform cleaning with the UV-lamps turned ON or OFF. Refer to step 3
below and section 5.2.2.6 on page 69.
3. Establish the cleaning solution.
When establishing the cleaning solution, it is important to start with the
least aggressive or abrasive liquid such as DI water. DI water will often be
adequate, but may require more frequent cleaning cycles. Other potential
cleaning solutions are:
• 50/50 mix (by volume) of H
3
PO
4
and Na
2
O
8
S
2
(UV-lamps ON or OFF)
• 1.0 M sodium hydroxide
• 5% NaOCl/CLOROX (UV-lamps OFF)
• 10% HCl (UV-lamps OFF)
• 5% Acetone (UV-lamps OFF)
If a cleaning agent has been used in another application containing the
same substances found in the sample(s), that cleaning agent can usually
be applied in this analyzer. Take caution when choosing the cleaning
solution. Take into consideration the materials that come in contact with
the sample and any gases or by-products produced.
3.8 Storage and Handling Tips
Even carefully prepared low TOC water can be easily contaminated by
atmospheric CO
2
. Follow the guidelines below to slow contamination:
• Use glass containers for mixing and storing.
• When not in use, seal calibration standards within an inert atmosphere so
that ambient CO
2
will not contaminate the solutions. Plastic membranes,
such as Parafilm
®
, will not keep out carbon dioxide.
• Refrigerate samples containing volatile components.
• Basic solutions absorb more ambient CO
2
than complex solutions.
• Cold water absorbs more ambient CO
2
than hot water.
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