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【答案】应助回帖
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感谢参与，应助指数 +1
mylllyn: 金币+2, ★★★很有帮助, Thank you so much! 2012-08-23 09:32:06
You also can use titration method to determination of Zn compounds , below is the procedure. Maybe it can help you.
1. Accurately weigh a sample containing approximately 0.5 meq of the metal into a 250 ml beaker.
2. Dissolve the sample in de-ionized water or by the addition of acid, heating may be necessary. Keep the beaker covered with a watch glass.
3. Allow the solution to cool to room temperature.
4. Pipette 15.0 ml of the standardized 0.05M EDTA into the beaker.
5. Dilute with about 50 ml of de-ionized water. Adjust the pH to 5 with dilute NaOH.
6. Add 10 ml of the sodium acetate buffer.
7. Heat the solution to boiling, then continue heating for three more minutes.
8. Let the solution cool to room temperature.
9. Add 10 ml of the ammonium acetate buffer solution, 75 ml of 2-propanol and ~1 ml of dithiazone indicator solution.
NOTE: The dithiazone indicator in acetone is made fresh as needed.
10. Titrate the solution with standardized 0.02M ZnSO4 to a red endpoint.
Calculation:
%(Zn,Ga,Al,In) = [(VEDTA)(NEDTA)-(VZnSO4)(NZnSO4)](MW)(100)/(sample weight) |
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