Sample Collection; Sample Measurement - EUTECH INSTRUMENTS WATERPROOF C401 COLORIMETER Instruction Manual

Measurement: Chlorine, Free & Total
Chlorine, Free & Total
Measuring Hints & Tips

2.4.1 Sample Collection

Chlorine determination must take place as soon as possible after the
sample is taken or else low results may be obtained.
Plastic containers should not be used to collect the sample because these
may have a high chlorine demand which will lead to low reading results. It
is advisable to wash the container with sample water before the sample is
collected.
Avoid agitating the sample excessively as this may also result in low
results.

2.4.2 Sample Measurement

If the pink color forms and then rapidly fades, this is an indication that the
chlorine concentration may be very high. If this is the case, dilute the
sample with de-ionized water and retest. Multiply the result by the dilution
factor used.
Example: if the sample was diluted 2:1 with de-ionized water (i.e. 1 part
sample water to 1 part de-ionized water), the result is multiplied by 2 to
give the true concentration of the original sample.
Note: Results obtained by this method will not be as accurate as stated in
this manual because some chlorine will be lost in the dilution process.
After use, the vial should be cleaned thoroughly to avoid contaminating the
next sample. Do not use household cleaners as these may have a
chlorine demand which will lead to low results on subsequent tests.
After testing Total Chlorine give extra attention to cleaning the vial as any
residual reagent will affect any subsequent Free Chlorine tests.
advisable to use separate vials for Free and Total Chlorine.
C401/301/201/102/101
11
It is