Advanced Instruments 4250, User Manual

Page: 44 / 121

CAUTION T he heat transfer fluid contains hazardous chemicals.
Consult the material safety data sheet (MSDS) and use
appropriate personal protective equipment.
CAUTION Heat transfer fluid can become contaminated with sample
material which may be considered a biohazard. Use appro-
priate cautions during removal and disposal of sample
tubes after testing to prevent heat transfer fluid remaining
on the tube exterior from contacting personnel or the
instrument surface.
11. Gently wipe the probe, stir/freeze wire, mandrel and the top of the
freezing chamber (in that order) with a soft, clean, dry, lint-free
paper tissue after each test, to avoid contaminating the next sample.
Be careful not to bend the probe or stir/freeze wire.
12. Repeating steps 1-11, test two to four more aliquots of the same ref-
erence solution or standard to check repeatability and accuracy
before running tests on unknown samples. Follow the techniques
recommended on page 20, Repeatability Tips. When checking cali-
bration and repeatability with standards or reference solutions, it is
usually best to average the readings from three to five aliquots of
each sample to avoid error.
If you are running the instrument for the first time, it is recommend-
ed that you follow the Lactrol
®
530 Reference Solution samples
with bracketing calibration standards to check the instrument accu-
racy and linearity over the range of interest.
If the instrument accuracy on the reference solution (and/or calibra-
tion standards) is not satisfactory, refer to Chapter 4, Calibration.
If the instrument repeatability on the reference solution (and/or cali-
bration standards) is not satisfactory, refer to Chapter 4.
If the accuracy and repeatability on the reference solution (and/or
calibration standards) are satisfactory, you may begin testing
unknown samples, using exactly the same test procedure as for the
22
Advanced
®
Cryoscope Model 4250 User’s Guide