j. With “[stir] [freeze]” displayed while running the stir/freeze
test, press the < button. The vibration blur at the very tip of
the stir/freeze wire for proper sample stirring of 2-mL to 2.5-
mL samples should be between 1/8 and 1/4” or between 3 and
6 mm. That amount of stirring is necessary to minimize tem-
perature gradients in viscous samples but more than 1/4” or 6
mm can cause poor repeatability or frothing which may make
it impossible to reliably determine the freezing point of certain
samples.
k. If the stir vibration amplitude is not correct, press STOP twice
to exit the TEST menu and press SETUP to enter the SETUP
menu.
l. At “Select Setup Item”, press the START button. The dis-
play will change to “Setup Menu #: 0”.
m. At “Setup Menu #: 0”, press the 4 button, then press
ENTER. The display will change to “Set Stir Amplitude”
(this menu item may alternatively be located by stepping for-
ward or backward from “Select Setup Item” with the > or <
button).
n. At “Set Stir Amplitude”, press the START button. The stir/
freeze wire will begin to vibrate and the display will change to
“Amplitude = xx”, with “xx” being some two-digit number
around 50.
o. Looking across the stir/freeze wire toward the probe, you
should be able to see a stir vibration blur at the very tip of the
stir/freeze wire. For 2-mL to 3-mL cryoscope operation, the stir
vibration blur at the very tip of the stir/freeze wire should be
between 1/8 and 1/4” or between 3 and 6 mm. That amount of
stirring is necessary to minimize temperature gradients in vis-
cous samples but more than 1/8 to 1/4” or 3 to 6 mm can cause
poor repeatability or frothing which may make it impossible to
reliably determine the freezing point.
74
The Advanced
®
Model 4C3 User’s Guide
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