Eicom ENO-30, User Manual

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27 | P a g e
6-5. Standard Solution
Dissolve the necessary amount of NaNO
2
and NaNO
3
in water taken directly from the purified
water tap. Then prepare a standard curve by diluting into water, Carrier solution, or the same
solution as the sample is in.
6-6. Waste

Collect Carrier and Reactor Waste into a bottle. This will be mainly an acidic 10% methanol
solution with significant cadmium levels.

The reduction column contains cadmium which slowly resolves into waste. The cadmium
in the waste can be concentrated by the method shown below. (If the total mass is small,
disposal cost for disposal can be reduced.)
Method to Concentrate Cadmium
1. Add 12 g NaOH for 1 L waste liquid and dissolve.
2. Dissolve 11 g of FeCl
3
-6H
2
O in 100 mL water, add to waste, and mix well.
3. Let precipitate for one day.
4. Filter the precipitate. The remaining supernatant should have low enough cadmium for
normal disposal.
6-7. Prepare for Analysis

Check the amount of Carrier and Reactor. Make fresh Carrier and Reactor as necessary.
For high sensitivity analysis, all solutions should be made fresh.

Aged or pink colored Reactor or very old Carrier will cause high noise generation and
reduce sensitivity. If the Reactor solution is stored in a transparent glass bottle covered
with aluminum foil, it’s easier to confirm the color of the solution.

Put the ends of the Carrier and Reactor inlet tubes into the bottom of each bottle. Check
degasser and pump markings to be sure. Cover the tops of each bottle with parafilm to
prevent dust falling in and to help hold the tubes in place.

Put the end of the pump seal wash inlet tube into the bottom of a bottle containing fresh
super pure water. Prime the seal wash lines before starting pumps.

Fill the autosampler wash bottle with fresh water or top off the 10% methanol.

Prepare a fresh precolumn if necessary.

Make sure the two-way joint is in place of the column.