BUCHI SpeedDigester K-439 - Manual (Page 44)

6 Operation
44 K-439 Operation Manual, Version A
➥ Depending on the sample material and acid / catalyst composition it might be necessary to vary
the digestion temperature at different time intervals (digestion method).
At the end of an Automatic digestion confirm the corresponding info message "Digestion done" by 6.
pressing OK. At the end of a Manual digestion press Stop to finish the process, then switch off the
instrument via the mains switch.
➡ The samples are now digested. Follow-up actions are described in section 6.10.
6 .9 Performing a peroxide digestion process
This section is divided into two consecutive sub-sections (6.9.1 and 6.9.2) and follow-up actions in
section 6.10. Do not skip or mix up these steps to ensure safe handling and best performance.
Note
Application notes are available for various samples at Buchi. These notes work as digestion recipes
and give detailed instructions how to process specific sample materials. For application notes,
contact your Buchi application specialist or your local distributor.
The 20 predefined Buchi standard methods help to operate the instrument "plug and play" and as a
basis to develop your own methods.
6 .9 .1 Preparational steps
Start-up the SpeedDigester. 1.
Let the system heat up (Preheat function in Automatic mode) 2.
Prepare the sample tubes according to the type of digestion under safe conditions. 3.
➡ The samples are now ready to be digested.
6 .9 .2 Starting a digestion process
Install the rack(s) according to section 6.7.3. For peroxide digestion a 'Suction module H 4.
2
O
2
' with
funnels must be installed!
➥ Place glass caps (order no. 040049) into every unused position of the rack
➥ Place insulation caps (order no. 11056024) into every unused position at the insulation plate
➥ To securely withdraw harmful fumes, switch on the suction unit (Scrubber or water jet pump)
before inserting the racks into the instrument!
The digestion process starts, as soon as the sample tubes heat up in the instrument. 5.
➥The Scrubber must be switched on.
➥If the Scrubber is directly connected to the K-439, it will start as soon as "Step 1" of the
selected method starts and stops after the cooling-down time defined within the method is
finished.
➥ Depending on the sample material and acid / peroxide composition it might be necessary to vary
the digestion temperature at different time intervals (digestion method).
➥ During the digestion process it is necessary to add peroxide. Carefully and slowly(!) add peroxide
into every sample probe via the funnel of the suction module (see following illustration).
At the end of an Automatic digestion confirm the corresponding info message "Digestion done" by 6.
pressing OK. At the end of a Manual digestion press Stop to finish the process, then switch off the
instrument via the mains switch.