eutech-instruments waterproof c401 colorimeter Manuale Utente

Measurement: Chlorine, Free & Total

 

 

C401/301/201/102/101 

 

 

 

13

6. 

Subtract the result obtained in step 5 from the result obtained in step 
1 to give the true result. 

To correct for any reagent added to the sample to neutralise it, a dilution 
correction factor must be used: 

 Final Volume ÷ Initial Sample Volume = Correction Factor 

The final volume can be calculated by adding together the initial sample 
volume and the volume of neutralising reagent used: 

Final Volume = Initial Sample Volume + Volume of Neutralising Reagent. 

The result from a test can then be multiplied by the Correction Factor to 
give the true result. 

If reagents are added from the supplied dropper bottles, then 25 drops is 
equal to 1ml. 

Example: 

 

50ml sample is neutralised using 50 drops of 1N Sulphuric Acid, 

and each drop is 0.04 ml. 

 

Initial Sample Volume = 50ml 

 

Volume of Neutralising Reagent added = 50drops X 0.04 ml= 2ml 

Final Volume = 50ml + 2ml = 52ml 

Correction Factor = 52/50 = 1.04 

A test result of 1.00ppm would then become 1.00ppm X 1.04 = 1.04ppm 

Producing chlorine standards is a difficult procedure that should only be 
attempted by trained laboratory staff. Details of preparation techniques are 
not provided in this document. 

The prepared chlorine standard may be used to check the accuracy of the 
meter or to re-calibrate the meter.  In almost all cases it is recommended 
to use the default factory calibration. 

 Prepare a standard in the range 0-

6ppm (it is advisable to check a standard at near the concentration usually 
tested for using the meter). Use this standard in place of the sample water 
in the above test method. Repeat the measurement 5-7 times with 
different sachets and average the results. The result obtained should be 
approximately the value of the standard used (please refer to instrument’s 
specifications for data on meter precision and accuracy).