Genevac HT-8 & HT-12 Series II Evaporating Systems
04-4541
Issue 1-9 – June 2008
Page 57 of
64
How it Works
The auto-defrost and drain enhanced condenser has the following features:
•
Enhanced condenser draining with minimum hold-up design
•
Automation of the drain valves
•
Specific defrost of condenser outlet pipe
•
Mid-method short defrost and drain to remove volatiles
•
Automated full defrost and drain at end of method
Auto-Defrost and Drain will appear as an option in the programming page when entering a method. Select the
method to enable it – for details see the programming guide in the user manual. The evaporator will perform in
one of two ways depending on whether the method is part of a linked series of methods:
•
If the method is stand alone and not linked to any other method, then when the evaporation method
has ended the system will do a full defrost and then drain condenser automatically.
•
If the method is linked, and has other methods after it, then at the end of the method the system will
perform a short defrost sufficient only to thaw any frozen solvent trapped in the outlet pipe, then drain
the condenser. When this is complete, it will automatically continue with the next linked method
•
If the method has other methods linked to it, but is the last in the chain, then at the end of the method
the system will do a full defrost, and drain the condenser automatically.
When to use Auto-Defrost and Drain
Auto-Defrost and Drain has two main functions:
1. to automatically drain the condenser mid-process to eliminate volatile solvents, enabling the system to
reach full vacuum in the later stages of evaporation. This allows the system to achieve better final
drying of the sample, and to get better evaporation of mixtures of solvents with widely differing boiling
points.
2. to automatically defrost and drain the condenser at the end of the method, saving the user time. This
means that for an overnight method which finishes before the user comes to the Lab in the morning,
the system has defrosted, drained and is ready to use straight away. This has a benefit for any
solvent.
The second of these requires no further explanation, however, there are a number of applications for the first
application – the intermediate defrost and drain. These include:
•
Drying of HPLC fractions where high vacuum in the final stages of evaporation is beneficial
•
Use of the Genevac fast lyophilisation method for HPLC fractions, where high vacuum in the latter
stages of the process is essential
•
Evaporation of DMF or DMSO mixed with a volatile solvent, e.g. dichloromethane (also known as DCM
or methylene chloride) where the mixture of solvents necessitates high vacuum for the high boiling
point solvent which is removed last, but where the volatile solvent removed first will sit in the condenser
and spoil the level of vacuum which can be achieved in the latter stages of the run.
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