4 method 2, Method 2 – Metrohm 824 Easy Sample Changer User Manual
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4.4 Method 2
824 Easy Sample Changer,
Standard methods
31
4.4 Method 2
Use:
For simple titrations (including KF titrations) or pH measurements (with-
out calibration). The initial addition of auxiliary reagents or solvents is
possible.
Required instruments:
•
Metrohm titrator (Titrino or Titrando) or pH meter
•
Metrohm Dosimat (optional)
•
Metrohm 802 Rod Stirrer or 741 Magnetic Stirrer
Features:
After each determination the electrode is briefly immersed in the condi-
tioning beaker (dipping). The direction of the rack rotation is controlled
so that samples which have not yet been processed are not contami-
nated by drops falling from the electrode.
Preparation:
Fill a sufficiently large conditioning vessel with a suitable solvent and
place it in the highest rack position.
Procedure:
•
(Start sequence) Initialize the sample changer
•
Move to sample and lower lift to working position
•
Switch on stirrer
•
If a Dosimat is connected (optional): add auxiliary reagent or sol-
vent and wait until addition is completed
•
Start titration/measurement and wait until it is completed
•
Switch off stirrer
•
Move lift to rotating position and allow electrode to drip
•
Move to conditioning beaker in front of the tower and immerse
electrode
•
Stir 5 seconds
•
Move lift to rotating position and allow electrode to drip
•
(Final sequence) Move to conditioning beaker and immerse elec-
trode