34849 Hydranal Water Standard

This standard is intended for the titer determination of volumetric Karl Fischer reagents. It is also suitable for testing reliability of KF analyses according to different norms (e.g. ISO 9000 pr ISO 17025). 1g contains approx. 10mg water. The exact amount of water is given on the Report of Analysis, which is supplied with each pack.

Use for determination

The ampoule has a predetermined breaking zone. Protect yourself by wearing gloves. Open the ampoule directly before use. Atmospheric moisture can penetrate in an open ampoule, or very dry air can absorb water and therefore falsify the results. For expiration data for the closed ampoule see label and report of analysis.

1. Prepare the titration vessel in the usual way, fill up the reagent and set the titration parameters.

2. Add the chosen solvent to the titration vessel and titrate to dryness (pre-titration).

3. Snap off the top tag of the ampoule at the predetermined breaking zone.

4. Rinse a glass syringe with approx. 0.5 mL standard and draw the rest of the standard immediately into the syringe.

5. Add 1-2 mL standard (= 10-20 mg water) by back weighing to the titration vessel.

6. Carry our the titration and repeat the procedure 1-2 times.

7. Calculate the titer according to the following data:

T = (E · W)/Vol

T = Titer (in mg water per mL)

E = Weight of Standard (in g)

W = Water content of Hydranal Water Standard as given in enclosed report of analysis (in mg/g)

Vol = Volume of consumed titrating agent (in mL)

Testing the reliability of analyses

If the result of a sample does not seem to be adequate, we recommend controlling the recovery rate. After analyzing the sample, carry our a standard check: add a known amount of Hydranal Water Standard and analyze it the same way as the sample. The amount of added water should be similar to the water amount in the sample. The recovery rate should ideally be within the expanded measurement uncertainty stated on the report of analysis. Literautre gives varying statements about recovery rates. Recommendation of Hydranal Technical Service:

For 10.0 mg water max. ±0.2 mg

Note

Please note that the plastic tubing used in many machines is not impervious to atmospheric moisture and therefore the titer of reagent in the tubing will decrease over time. Flush the tuving carefully prior to any titer determination.

Report of Analysis

Product: Hydranal-Water Standard 10.0

Cat. No.: 34849

Water content: 9.99 mg/g

Expanded uncertainty: 0.20 mg/g (k=2; 95% confidence interval)

The water content is analyzed under ISO/IEC 17025 accreditation by volumetric titration on 12 samples according to ISO 760 and ASTM E 203. The coulometric KF titration was used as a second technique to confirm the reliability of the specified water content. This standard is traceable to high-purity water and verified against NIST SRM 2890.

注：以上信息僅供參考，以產(chǎn)品附帶證書為準。