Metrohm 832 KF Thermoprep - Manual (Page 22)

4.5 Working procedure
18
832 KF Thermoprep, Operation
4.5.1 Preparing the 832 KF Thermoprep/756/831 Coulometer system
1. Switch on the 832 KF Thermoprep. The oven heats up automati-
cally to set temperature T1 or T2.
2. If necessary use the set value switch to alter set temperature T1 or
T2.
3. Place an empty sealed vial in the oven.
4. Lower the needle until the stop is reached. Both hands should be
used for safety reasons.
5. Switch on air pump (if N
2
is used open the nitrogen valve).
6. Check the gas flow at the flowmeter 17 and alter it if necessary
(optimal range: 40…60 mL/min).
7. Start the 756/831 Coulometer and allow it to be conditioned.
8. Let the oven heat up until the set temperature is reached and the
coulometer cell is conditioned.
4.5.2 Determination with blank value subtraction
Determination of blank value(s)
1. Load a method for a blank value determination (e.g. Blank) into the
coulometer. The mean value of the blank value determinations
should be stored as a common variable. Set the extraction time to
300 s.
2. Start conditioning the coulometer (with the <START> key).
3. Wait until the set temperature has been reached and the coulom-
eter cell is conditioned.
4. Start the blank determination at the coulometer with <START>.
5. Raise the needle fully and remove the conditioning vial from the
oven with the crimping pliers.
6. Insert an empty sealed vial (blank sample) in the oven using the
crimping pliers.
7. Lower the needle until it reaches the stop and pierce the septum
cap.
8. After the determination wait for post-conditioning to be completed
and, if necessary, carry out further blank value determinations, i.e.
repeat the procedure from item 3 onward.
Sample determination
1. Load a method for a sample determination into the coulometer.
The mean blank value, stored as a common variable, is to be sub-
tracted from the sample result. Set the extraction time to 300 s.
2. Start conditioning the coulometer (with the <START> key).
3. Wait until the set temperature has been reached and the coulom-
eter cell is conditioned.
4. Start the determination at the coulometer with <START>.