Hach BioTector B3500C, Руководство пользователя

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6.1.1 Sulfuric Acid Reagent
There are a number of factors which affect the purity of the sulfuric acid solution used by the BioTector. These
can take the form of inorganic or organic contamination. Inorganic contamination does not generally occur in
concentrated acids, but there could be some dissolved CO
2
present in the deionized water, which is used to
make up the acid solution. To remove any CO
2
dissolved in the deionized water used to make up the acid
solution, sparge the water with a CO
2
free gas such as Nitrogen.
Organic contamination has two main sources: Organics, which are present in the concentrated sulfuric acid,
or dissolved organics in the water used to make up the solution. The manufacturer will specify the level of
organics in the concentrated sulfuric acid. For the BioTector, this should be as low as possible. If the
deionized water generator is functioning correctly, then there should not be any organics in the deionized
water. Ideally, the level of organics should be less than 100

g/l (ppb).
The procedure for making up sulfuric acid solutions for the BioTector from concentrated acid is as follows:
Mixing Procedure for the Preparation of 6.0 N Sulfuric Acid Solution containing 350 mg/l Manganese
Sulfate Monohydrate:
Concentrated sulfuric acid is dangerous. The preparation of sulfuric acid
solutions should only be carried out by persons properly trained in the
handling of chemicals.
NEVER POUR WATER INTO ACID, ALWAYS POUR ACID INTO WATER!
Use eye protection and gloves.
Typically, concentrated sulfuric acid has purities of 96-98%. The procedures for both 1 liter and 25 liters of
acid reagents are described below.
The instructions below assume that the sulfuric acid used has a purity of 98%, which is the standard
commercial purity of sulfuric acid. When sulphuric acid at different purities are used, please refer to table 7
below.
1. To prepare an acid solution, always use deionized water, free from organic and inorganic carbon. The
conductivity of the deionized water used should be less than 0.5 µS/cm.
2. Blow through the deionized water with a CO
2
free gas such as Nitrogen or Oxygen, to purge the water
of any dissolved CO
2
.
3. Fill 75% of the container with deionized water.
4. a) In order to prepare 1 liter of 6.0 Normal acid solution, add 300.2 grams of 98% purity sulfuric acid.
Mix gently and add enough deionized water to make it exactly 1 liter.
b) To prepare a 25 liters acid solution, add 7505 grams of 98% purity sulfuric acid in stages. Adding
the sulfuric acid in stages will prevent the solution from heating up. Gently mix and then add
enough deionized water to make it exactly 25 liters.
5. Seal the container.
6. Gently shake the container to mix the acid with the water.
7. Add enough Manganese Sulphate Monohydrate catalyst (MnSO
4
.H
2
O), so that the acid reagent will
contain 350 mg/l (mg per liter) of MnSO
4
.H
2
O. For instance, for a 25 litres acid solution, add 8.75
grams of MnSO
4
.H
2
O and mix well.
8. Allow the container to stand for one hour, and gently shake again to ensure a good mix.
WARNING