6
TurboVap
®
96 Dual User Manual | © Biotage 2021
Determine Optimal Evaporation Conditions
Determine Optimal Evaporation Conditions
There are several variables that influence the solvent
evaporation process. These include sample composition,
well plate dimensions, nozzle depth, gas temperature, plate
temperature, solvent volume, solvent boiling point, solvent
vapor pressure, and general humidity. Given the complexity
behind the combined effects of these variables on evaporation
rates, suggestions for optimal evaporation/concentration are
listed below.
Determine the Appropriate
Evaporation Mode
There are three evaporation modes available (see Figure 7):
»
Manual:
Evaporate until the user presses the
Stop
button.
»
Time:
Evaporate for a set period of time.
»
Method
: Evaporate according to pre-set instructions,
see "Set Up a Method" on page 15.
Figure 7.
The different evaporation modes that can be selected in the
software.
Each mode has different advantages.
Manual
and
Time
evaporation modes offer a quick approach that is easy to use,
whereas
Method
mode offers the benefits of programming four
steps with the option to ramp the gas temperature, flow rate,
and lift height over a specified time.
General Evaporation Settings
Consider the following when selecting the evaporation settings:
»
For best results, avoid cold starts. Always wait
until the system reaches its set temperatures and
flow rates before starting an evaporation run.
»
The environmental conditions outside of the system should
be held constant while an evaporation run is in progress.
»
If the gas or plate temperatures are below or exceed the
accepted level during evaporation, nonuniform evaporation,
analyte loss, or degradation of analytes may be observed.
»
Do not allow samples or solvents to boil.
»
The evaporation time of samples decreases with increasing
sample cleanliness. The presence of sample detritus or
particulates will have a negative effect on evaporation time.
»
To determine the appropriate evaporation time for
the samples, use neat solvents in
Manual
mode
and monitor the elapsed time for the samples
to evaporate to your desired liquid level.
»
Always consider analyte and solvent volatility
when setting evaporation parameters.
»
If the temperature settings in one cabinet greatly
exceeds that of the other when the two cabinets are
operating independently, the likelihood of experiencing
cross temperature effects between the two cabinets is
increased. Thus, it is important to consider the settings
of both cabinets before an evaporation run is initiated.
Determine the Appropriate Gas Flow
Consider the following when selecting the operating gas flow:
»
If the liquid level is less than 50% of the well volume,
set the gas flow to the lowest setting and increase
the lift height until it can be confirmed that the
gas reaches the liquid without splashing.
»
To conserve gas and determine optimal flow rates, begin
with a low to moderate gas flow of 25 to 40 L/min.
»
As the sample volume decreases during the evaporation
process, increase the gas flow manually or use the
Ramp feature (see "Evaporation Parameters" on page
15) to increase the rate of evaporation. This will
assist in reducing the overall evaporation time.
»
To decrease evaporation time, use the highest gas
flow possible without causing splashing. Higher gas
flow generally increases solvent evaporation rates.
»
Excessively high gas flow can cause analyte loss
and cross-contamination due to splashing.
Note:
To achieve the correct gas flow, the correct manifold
configuration must be selected (see "Common Settings" on
page 8).