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4.3 Calibration Standards
TN400 turbidity meter adopts US EPA certified Reagecon high molecular weight polymer
turbidity standard solution. Compared with traditional Formazin standard solution,
Reagecon standard solution has a lot of advantages, such as non-toxicity, high accuracy,
long shelf-life, traceable to NIST and so on. The standard solution supplied in the TN400
turbidity meter kit has a shelf-life longer than 12 months (from the date of manufacture).
Please check the date on the bottom of the vials before using.
4.4 Calibration Notes
1) Place turbidity meter on a flat and level surface, please don't hold
the instrument in hand.
2) When place calibration vial into measuring well, the arrow mark on
vial cap must be aligned with the arrow mark on the measuring
well. See diagram-4
3) Apply little drop of silicone oil on the calibration vial and wipe clean
with soft cloth to cover up the scratches and flaws on the glass
surface. It's helpful for light scattering. Please don't apply too much silicone oil, and the
vial must be wipe and cleaned up. Otherwise it will affect measuring accuracy. After
wiping and cleaning, set the calibration vial still on the table for at least 2 minutes to
eliminate micro bubble in solution. For 0.02 NTU calibration vial, the standing time
should be at least 5 minutes.
4) If use Formazin standard to calibrate, please note the diluents Formazin standard is not
stable. Please make sure to use new prepared Formazin standard to ensure calibration
precision.
5) Please don't open cap of calibration vial. Inspect the expiration of calibration standard.
Make sure the calibration vial free from dust, dirt, fingerprint and scratch.
6) Please use same method to calibrate every time, and establish standard operating
procedure.
5. Turbidity Measurement
5.1 Sample Vial Handling
1) There are 3 sample vials contained with the instrument, marked 1#, 2# and 3# on the
vial cap. There is also same number in the bottom of sample vial. The number of
sample vial should be same with that of vial cap, don't mix up. Please always use 1#
sample vial to measure low turbidity less than 5 NTU.
2) Sample vial has been meticulously cleaned and disinfected. It can be used directly for
the first time. When subsequent using, sample vial must be strictly cleaned as following
steps: wash the interior and exterior of the vial in a detergent solution
rinse with clean distilled water or deionized water
solution twice
fill sample vial with sample solution
rinse sample vial with sample
- 8 -
Diagram- 4
repeatedly
screw the vial cap tightly.
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