P-OQ1011-3276-J01
2
Operational
Qualification (OQ)
Automatic Digital
Refractometer RX-5000i
for actual use before setting a standard. Refer to the product literature and/or
instruction manual for the specifications of the RX-5000i. These specifications are
guaranteed at the time brand-new instruments are shipped out by the manufacturer. It is
extremely difficult to produce an accuracy level that is better than the stated
specifications due to various environmental factors of the end-user’s site. A standard of
evaluation equal to or lower than the specifications is generally considered reasonable.
An example of such standard is: ±0.00006 nD, ±0.05% Brix accuracy.
3
．
Validation of Measurement Accuracy and Repeatability
Measurement values of the RX-5000i may be checked for accuracy and repeatability by
measuring a sample of known concentration.
The optical system of the RX-5000i based on the principle of light refraction operates in
conjunction with the electric elements, electronic circuit, etc. to calculate the refractive
index.
Select points within the measurement range to test the accuracy, repeatability, and span.
This procedure almost replicates the performance tests executed for calibration
purposes.
The accuracy of the RX-5000i is expressed as ±0.0000X for refractive index and ±0.0X%
for Brix.
4
．
Necessary Items
1) Samples: distilled water, 10.00% Brix standard sucrose solution, 30.00% Brix standard
sucrose solution, 1.51 nD standard liquid, round sheets
2) Plastic spoon or pipette, tissue paper, ethyl alcohol, USB flash drive
3) Measurement data log sheet
5
．
Instrument Preparation
1) Turn the power on to the RX-5000i. The opening (home) screen will be displayed. If
connecting a printer, turn on the printer first. The printer will print the opening
message.
2) Let the instrument warm up for at least 20 minutes. Touch “MEASUREMENT,” and the
measurement screen will appear. Check the MODE settings in the lower left corner of
the screen. It should be in MODE1, and the target temperature should be 20.00
℃
.
Touch “MODE” to adjust the settings.
3) Make sure that the date and time displayed are correct.
4) Check the print settings. From the set up screen, touch “PRINTER,” and the print
settings screen will appear. Set it to print measurement values in nD and Brix as well as
measurement temperature.
5) Make sure that the default scale on the measurement screen is Brix.
