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Using the same sample vial to calibrate and measure can eliminate the error caused by
different vials, thus reaching higher accuracy. For example, add distilled water to 1
#
vial for
calibration and then add sample solution to 1
#
vial for measurement. Note that the solution vial
should be rinsed thoroughly when changing solutions.
d)
Zero Turbidity Error Reminder:
0 NTU is the reference point for low-turbidity measurement. Due
to the complexity of turbidity measurement, various inaccuracies resulting from instruments,
solutions, vials, and operations can cause large errors at the 0 NTU point, which has a great impact
on the measurement accuracy of low turbidity solutions. When the reading is displayed as 0.00 NTU,
if a positive error occurs, a 0.0 NTU calibration solution can be used for verification test. If a
negative error occurs, it cannot be verified. For this instrument, there is a Zero Turbidity Error
Reminder function. If the negative error at the zero point exceeds the preset value, it will prompt
users to recalibrate 0.0 NTU. At this time, users can press to measure 1 or 2 more times. If
the prompt appears continuously, please recalibrate 0.0 NTU. In addition, compared with other
calibration solutions, The 0.0 NTU solution is more prone to deterioration and error. When the 0.0
NTU solution is found to be turbid or flocculent, or if it is judged that it may be out of tolerance based
on the experience of sample tests, please replace the 0.0 NTU solution in time according to the
requirements in Section 4.1b.
e)
High turbidity calibration requirement:
For turbidity measurement greater than 2 NTU, it is
recommended to calibrate once a week, or to test a calibration solution close to the sample solution.
If the error is large, the instrument needs to be recalibrated.
f)
The instrument does not automatically recognize the calibration solution. If the wrong solution is
selected for calibration, the measurement will be completely wrong. In this case, it can be restored
by recalibrating with the correct calibration solutions.
g) Place the instrument on a flat and level surface. Do not hold the instrument in your hands while
operating.
h) If using Formazin standards for calibration, please note that the diluted Formazin standard is
unstable. Please make sure to use the freshly made Formazin standard to ensure calibration
accuracy.
5
T URBIDIT Y MEAS UREME NT
5.1 Sample Vial Handling
a) 6 sample vials are included in the test kit. The cap is marked with 1
#
to 6
#
, and the bottom of the vial
also has the same number. The number of the vial and the cap should always be the same. *Pay
attention that 1
#
and 2
#
vials are only for low turbidity solution measurement. (< 2 NTU)
b) The vial has been rigorously cleaned and sterilized. They can be used directly for the first time. For
subsequent uses, follow the steps below to perform a thorough cleaning.
⚫
Clean the inside and outside of the sample vial holder
with detergent → rinse with distilled
water or deionized water multiple times → Rinse the vial twice with the sample solution → Pour
the sample solution into the vial → Close the cap.
