Bruker CryoProbe User Manual

46 (107) BRUKER CryoProbe User Manual
Standard procedures
CAUTION: Never cool the cavity below the sample temperature lower limit
as given on the specific CryoProbe L
IMITATIONS - WARNINGS sheet, even
if the VT gas cooling would permit to do so.
Table 4.8. Determine lowest sample cavity temperature
step action
t.1 Insert a sample with a low melting point, e.g. ‘Lineshape’ (mp =
- 64°C).
t.2 Select the lowest allowed sample temperature as given on the spe-
cific L
IMITATION - WARNINGS sheet of the CryoProbe, e.g. -10°C.
t.3 Set the VT heater power limit according to the L
IMITATIONS - WARN-
INGS sheet. Leave the VT heater off.
t.4 Select the desired VT gas flow rate.
NOTE: A high VT gas flow is generally to be preferred for a CryoProbe
as long as it does not lift the sample. See the minimum flow rate on the
‘L
IMITATIONS - WARNINGS’ sheet and the explanations in "H2O sam-
ples" on page 60.
t.5 When the sample temperature has stabilized after a few minutes, write
down its value. This is which will be used later for the setup of
NMR experiments (see "Sample temperature control" on page 55
).
t.6 NOTE: The following determination of in the presence of a
BCU05, step t.6
to t.9, is time-consuming (~1h) because the gas cooler
needs time to reach its operating temperature. If is not
needed now, skip this test and execute it when convenient.
If a BCU05 is present, switch it O
N.
t.7 Make sure that the sample temperature is set to the lowest allowed
value as given on the specific L
IMITATION - WARNINGS sheet of the Cryo-
Probe, e.g. -10°C.
t.8 Switch the VT heater on.
NOTE: Here, the VT heater is needed only for the protection of the
Cryo Probe during the unattended operation of the BCU05. While the
sample temperature is above the allowed lower limit (e.g. -10°C), the
VT heater power must be 0%.
NOTE: Observe the sample temperature for a minute and make sure it
does not rise in an uncontrolled way. If it rises too far or too fast, reduce
the VT heater power limit such that the sample temperature stabilizes.
In emergency, eject the sample. Never interrupt the VT gas flow!
T
limit, low
T
min
T
min, BCU05
T
min, BCU05

Bruker CryoProbe Specifications

General

Brand	Bruker
Model	CryoProbe
Category	Laboratory Equipment
Language	English