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3.4 Performance Check
About once every 6 months, measure a standard sample and check that there are no
problems with the instrument. If there is a problem, contact your nearest JASCO
distributor.
Use 5%(W/V) aqueous sucrose solution as the standard sample. The specific optical
rotation of aqueous sucrose solution is = 66.5°.
Note: Regarding the standard sucrose
American NIST grade sucrose is recommended as the sample sucrose for
optical rotation measurement.
As a secondary standard to NIST sucrose, JIS special grade sucrose from
Wako Junyaku KK is recommended. The crystallization of this sucrose is
good, so there is no need for heat processing to remove water, and the
specific optical rotation is considered equivalent to that of NIST within
experimental error.
(1) Turn the power switch on and allow the instrument to warm up for about 30
minutes.
(2) Set data mode to optical rotation (alpha).
(3) Set the parameters as follows.
Lamp : WI or Na
Wavelength(filter) : 589 nm
Integration: 5 sec
Sample chamber aperture: φ8 mm
Auto. meas.: On
Auto. print: On
(4) Press the [Zero] key. The value of the data display changes to 0.000.
(5) Cell blank measurement and clear
1) Fill distilled water in a clean 100 mm cell, set the cell in the cell holder of the
sample chamber, then close the lid. Measurement is automatically performed
and cell blank data is printed.
2) Press the [Zero] key. The value of the data display changes to 0.000.
Note1: Always place the cell in the same position in the cell holder, facing the same
direction.
Note2: Wipe the cell window free of water drops or other adhering contaminants to
ensure clean storage.
(5) Measurement of standard sample
1) Remove the cell from the sample chamber, discard the water, wash 2 - 3
times with 5%(W/V) standard aqueous sucrose solution, then fill the cell with the
sucrose solution.
2) Clean the cell window and set in the sample chamber. At this time, place
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