Metrohm 893 Professional Biodiesel Rancimat - Manual (Page 36)

4.3 Determinations
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893 Professional Biodiesel Rancimat
4.3 Determinations
4.3.1 Preparing the instrument and the accessories
The cleanliness of instrument and accessory parts is an indispensable pre-
requisite for reliable, reproducible and correct analysis results. Even
the slightest contamination could catalytically accelerate the oxidative
decomposition and lead to completely incorrect results. Therefore, always
observe the instructions for use of measuring and reaction vessels in this
chapter.
Check and prepare the instruments and vessels as follows:
1 Checking the positions for reaction vessels
￭ Check whether the positions in the heating block are clean and
empty.
Blow out contamination and dust in the positions with nitrogen.
If the instrument is not used, always seal the corresponding posi-
tions with the stoppers.
2 Filling the measuring vessels
NOTE
Only use measuring vessels and accessories which are abso-
lutely clean and in a flawless condition.
￭ Fill the cleaned measuring vessels with 60 mL distilled water
each.
For analysis times of more than 24 h approx. 7 mL more distilled
water must be added per day to compensate for the evaporation
loss, so that the electrodes remain safely immersed.
3 Inserting the measuring vessels
￭ Place the clean measuring vessel covers equipped with a PTFE
cannula on the measuring vessels.
￭ Insert the measuring vessels with the measuring vessel covers into
the openings provided for this on the 893 Professional Biodiesel
Rancimat while carefully guiding the connector plugs of the cover
into the electrode connectors.