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-         3 M KCl solution (224 g KCl in 1 L l reagent water)

Stock standard solutions (1

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l)

-         0.1 M borax solution (38.1 g borax in 1 L l reagent water)

-         0.5 M NaHCO₃ (42 g sodium bicarbonate in 1 L l reagent water)

-         0.1 M Na₂CO₃ (10.6 g sodium carbonate in 1 L l reagent water)

-         0.5 M Na₂CO₃ (53.0 g sodium carbonate in 1 L l reagent water)

Standard solutions (100

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ml)

-         5 mM alkalinity (pipet 2.5 mL ml 0.1 M Na₂CO₃ into 97.5 mL ml 0.7 M KCl)

-         20 mM alkalinity (pipet 10 mL ml 0.1 M Na₂CO₃ into 90 mL ml 0.7 M KCl)

-         40 mM alkalinity (pipet 20 mL ml 0.1 M Na₂CO₃ into 80 mL ml 0.7 M KCl)

-         50 mM alkalinity (pipet 10 mL ml 0.5 M NaHCO₃ into 90 mL ml 0.7 M KCl)

-         100 mM alkalinity (pipet 10 mL ml 0.5 M Na₂CO₃ into 90 mL ml 0.7 M KCl)

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Main Main

Main instrument panel

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The rate at which the titrator dispenses acid into the sample can be adjusted according to the expected alkalinity value. Higher alkalinities may require faster dispensing rates. The dispensing rate can be selected from a list of predetermined programs or a new dispensing rate program can be created.

Select Edit Rates from the main alkalinity interface Main instrument panel.

To create a new rate program:

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To start creating a standard ratio correction, select STANDARDS from the main alkalinity interface Main instrument panel.

1. Place 3 mL ml of standard in vessel. Add stir bar and immerse electrode in vessel. Confirm that the frit is in the solution.
2. Select Continue.  
3. Click START.
4. Insert the acid dispensing probe when prompted.
5. When finished, clean vessel and electrode. Repeat steps 1–4 until you have at least three consistent measurements per standard.
   
   Now go to the STND Manager, selected from the main alkalinity interface Main instrument panel.
   
   

1. Select the three measurements you want to average and click Average.
2. The window to the right shows the next step in which you can save the new standard ratio correction or replace an old one. Usually we save as a new ratio (e.g. 371_13august). The window showing the name creation is not shown.
3. Click Done.
   
   

   To select a standard ratio correction for subsequent measurements go to Setup in the main alkalinity interface.

   
   
   

This window also shows the electrode calibration values, the path to the datalog file, the default setting for the Drift Span , and where to select the standard ratio correction.

To select a saved standard ratio correction , double-click it.

Measuring samples

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The system is now calibrated, dispensing rates selected (generally rate and standard ratio correction selected. Generally, start with the slowest dispensing rate, assuming that the alkalinity will be around the value of IAPSO) and .  Same with the standard ratio correction selected (again, generally start with the IAPSO standard ratio correction and adjust according to what is measured in the samples).

Select SAMPLE from the Main instrument panel.

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Select the sample (IWS) from the LIMS database. Use the tree or type in the tree. Alternatively, type or scan in a Text_ID in the appropriate field. If you type in use a Filter Code IWS, the software will only bring up the IWS sample, which can be handy if your IW has a lot of children.

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Click START. The software will guide you through.

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After completing all the steps in the "We are watching you!" box, click GO. The pH measurement will commence.

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Insert the acid

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dispenser probe when prompted. Click GO. The alkalinity measurement will commence.

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When the titration is complete, a window appears to let you know that the analysis is complete. Click Ok.

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Analysis is complete. Click OK. Thiswill take you to the Gran-method window.

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A Gran-Method window appears with the results of the titration. Write the pH and the Alkalinity Cor value in the blue book. This is the result with the standard ratio correction applied to it. Click Ok/Save. This will upload the result to LIMS assuming the MUT uploader is active.
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When finished, clean vessel and the electrode.Click Ok/Save to save the results to the LIMS database. The value saved to LIMS and the value you need to note in the blue book is the “Alkalinity Cor” value. This is your result with the standard ratio correction applied to it.