How can the accuracy of an alkalinity result be checked?

Dokument-ID

Dokument-ID TE114

Veröffentlichungsdatum

Veröffentlichungsdatum 25.05.2022
Frage
How can the accuracy of an alkalinity result be checked?
Zusammenfassung
Checking the accuracy of alkalinity methods
Antwort
Accuracy of any method can be verified by using a standard of known concentration in place of a sample.  However, in the case of samples where an interference is suspected, a sample spike (standard additions test) should be performed. This procedure is slightly different depending on the method being used:

US ENG Alkalinity, Phenolphthalein and Total Alkalinity Method 8203, Digital Titrator_DOC316.53.01166:
1. Use the test procedure to measure the concentration of the sample.
2. Add 0.1 mL of Alkalinity Standard Solution, 25,000 mg/L as CaCO 3, pk/16 - 10 mL Voluette® Ampules (Product # 1427810) to the titrated sample.
3. Titrate the spiked sample to the endpoint.  Record the number of digits on the counter.
4. Add one more 0.1 mL addition of the alkalinity standard to the titrated sample. 
5. Titrate the spiked sample to the endpoint.  Record the number of digits on the counter.
6. Add one more 0.1 mL addition of the alkalinity standard to the titrated sample. 
7. Titrate the spiked sample to the endpoint.  Record the number of digits on the counter.
8. Compare the actual result to the correct (calculated) result. The correct result for this titration is 25 digits of the Sulfuric Acid Digital Titrator Cartridge, 1.600 N (Product # 1438901) or 250 digits of the Sulfuric Acid Digital Titrator Cartridge, 0.1600 N (Product # 1438801) for each 0.1 mL addition of the standard solution.  If much more or less titrant was used, there can be a problem with the user technique, reagents, apparatus or an interference.

US ENG Alkalinity, Buret Titration Method 8221_DOC316.53.01151
1. Use the test procedure to measure the concentration of the sample.
2. Add 0.1 mL of Alkalinity Standard Solution, 25,000 mg/L as CaCO 3, pk/16 - 10 mL Voluette® Ampules (Product # 1427810) to the titrated sample.
3. Titrate the spiked sample to the endpoint.  Record the mL of titrant added.
4. Add one more 0.1 mL addition of the alkalinity standard to the titrated sample. 
5. Titrate the spiked sample to the endpoint.  Record the mL of titrant added.
6. Add one more 0.1 mL addition of the alkalinity standard to the titrated sample. 
7. Titrate the spiked sample to the endpoint.  Record the mL of titrant added.
8. Compare the actual result with the correct (calculated) result.  The correct result for this titration is 2.5 mL of titrant for each 0.1 mL addition of the standard solution.  If much more or less titrant was used, there can be a problem with user technique, reagents, apparatus or an interference.
 

Hat dir diese Antwort geholfen?

Wird gesendet...
Vielen Dank für Ihr Feedback.
Beim Senden ist ein Fehler aufgetreten. Versuchen Sie es erneut.