Analytical Method: Analytical Quality Assurance, Standard for Total Hardness

Reagents:

Cat.No. 102121  Calcium nitrate tetrahydrate for analysis

Cat.No. 116754  Water for analysis

 

Preparation of a standard solution:

Dissolve 2.946 g of calcium nitrate tetrahydrate in a calibrated or conformity-checked 500-ml volumetric flask and make up to the mark with distilled water. The stock solution prepared according to this procedure has a concentration of 1000 mg/l calcium (corresponds to 175 °e).

 

Further investigational concentrations may be prepared from this stock solution by diluting accordingly.

 

Stability:

The stock solution of 1000 mg/l remains stable for one week. The diluted investigational solutions remain stable for one day.
 

 

For use with test kits:

Measuring range

110025

MQuantTM Total Hardness Test

<3 - >21 °d
<4 - >26 °e
<5 - >37 °f

110046

MQuantTM Total Hardness Test

>5 - >25 °d
>6 - >31 °e
>9 - >45 °f

117934

MQuantTM Total Hardness Test

<150 - >250 mg/l CaCO3
<1.5 - >2.5 mmol/l CaCO3<
<8.4 - >14 °d
<10.5 - >17.5 °e
<15 - >25 °f

108047

MColortestTM Total Hardness Test

1 - 100 mg/l CaCO3
0.1 - 5.6 °d
0.13 - 7 °e
0.18 - 10 °f

 

 

 

 

For use with test kits:

Measuring range

108039

MColortestTM Total Hardness Test

0.1 - 3.6 mmol/l CaCO3 (Ca)
0.2 - 20 °d
0.25 - 25 °e
0.36 - 35.6 °f

108312

MColortestTM Total Hardness Test

20 mg/l CaCO3

111104

MColortestTM Total Hardness Test

>1 °d
> 1.25 °e
>1.78 °f
> 7.1 mg/l Ca

116997

Reflectoquant® Total Hardness Test

0.1 -30.0 °d
0.1 - 37.6 °e
0.2 -53.5 °f

100961

Spectroquant® Total Hardness Cell Test

5 - 215 mg/l Ca
0.7 - 30.1 °d
0.9 - 37.6 °e
1.2 - 53.7 °f

 

Materials

     
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