...
- Remove electrode from cup.
- Rinse electrode with DI water in squeeze bottle.
- Blot the electrode dry with a Kimwipe. Do not rub the electrode, which could cause static charge buildup.
- Place the electrode in a storage container containing 3 M KCl.
- Rinse and dry the acid dispensing tip and stir bar.
- Pipette or pour the titrated alkalinity IW sample into a container to ship to repository or scientist.
- Write on label how much HCl was added during titration.
- Rinse the titration vessel cup with DI water and dry.
| Anchor | ||||
|---|---|---|---|---|
|
Editing Gran factor points
...
Data reports are not available at the instrument, but data can be viewed by selecting View Datalog (Figure 20) from the Main instrument panel. Also, the software appends the alkalinity results to the DAT file C:\ProgramData\IODP\Alkalinity. The best way to view the alkalinity values to be used in graphs and reports is via LIMS Reports. It is also highly recommended to record the alkalinity and pH values in the blue laboratory notebook to protect against inadvertent data loss.
Figure 20. Datalog.
Quality assurance/quality control
...
An analytical batch is a group of samples run together in one sequence, sharing a calibration curve, blanks, reference materials, and verification samples. The alkalinity batch size is 10 samples. Each batch of 10 unknown samples contains a sample to verify precision and a sample to verify accuracy.
Blanks
Blanks are not run for this method because DI water has no buffering capacity and would therefore fail the slope program. Thus, blanks are not applicable to this chemistry.
...
Analysis | Component | Unit | Description |
ALKALINITY | alkalinity | mM | Ability of a solution to neutralize acid to the equivalence point of carbonate |
pH | NA | Acidity or basicity of a solution (–log[H+]) | |
acid_quantity | µLµl | Amount of 0.1 M HCl added to the sample during titration | |
correction_factor | — | Correction factor for non-ideal behavior of samples to adjust calibration | |
ALK_QAQC | alkalinity | mM | Ability of a solution to neutralize acid to the equivalence point of carbonate |
pH | NA | Acidity or basicity of a solution (–log[H+]) | |
acid_quantity | µLµl | Amount of 0.1 M HCl added to the sample during titration | |
correction_factor | — | Correction factor for non-ideal behavior of samples to adjust calibration | |
slope | — | Slope of the calibration equation | |
intercept | — | Intercept value of the calibration equation | |
corr | Rho | Correlation coefficient of the calibration |
...
When the alkalinity titration finishes, the GRAN-METHOD screen window shows the slope information, correction factors, and the final alkalinity value (Figure 18).
Edit outlier Gran factor points, if necessary (see Editing Gran Factor Points). If . When satisfied with the results, click Ok/Save to load the values into LIMS.
...
LIMS.
Health, safety and environment
...
– | Make sure the probe storage container is filled with 3 M KCl solution and the reservoir is filled with 0.1 M HCl solution. |
– | Ensure no air bubbles are present in the acid dispensing line. Press DOS on the body of the titrator to push acid through the line and remove air bubbles. |
– | Change out the Drierite trap when ~50% of the color turns from blue to pink. |
| – | In case of a bubbling noise, top up your temperature-controlled water bath. Use tap water. Check titration vessel for air bubble space and eliminate if present. |
...