Opti-Trace User’s Manual
Page
13
Using the values from our example, “m” is calculated as:
m = (30 – 0)/(19 – 4) = 30/15 = 2
Substituting for “m”, when “y” = 0 and “x” = 4, (the blank values),
we can determine “c”
0 = (2 * 4) – c,
so, c = -8
This gives y = 2x – 8 ……..Equation (2)
4.
For any value of “x”, the sensor current, the corresponding sample concentration,
“y” can be found.
5.
Example: Suppose the output current = 10 mA,
then the sample concentration = (2 * 10) – 8 = 20 – 8 = 12 ppb.
Recommended Measurement Practices
1. Determining the Maintenance Interval
The flow cell should always be cleaned as part of the calibration routine. However,
it’s not essential to calibrate the sensor each time it’s cleaned. To determine the
necessary calibration/cleaning interval, follow these steps;
a)
Measure a sample of water with dye using the Opti-Trace
b)
Clean the Opti-Trace flowcell using the brush included in the accessories
c)
Re-measure the sample used in step (a).
d)
Calculate the difference in readings and determine whether the difference is
outside acceptable limits as defined in your application. If yes, it will be
necessary to reduce the amount of time between calibration/cleaning
maintenance.
2. Cleaning the Flowcell
For routine maintenance, clean the sensor with the supplied brush. For more
thorough cleaning, the next step is to use suitable cleaning liquids as described
below.
Proper eye and skin protection should be worn when using
acids to clean the sample cell.