Aztec 600 aluminium, ammonia, color, iron, manganese, phosphate
Single- and multi-stream colorimetric analyzers
Appendix C – Principle of Operation
IM/AZT6CR–EN Rev. J
87
C.7 Chemical Measurement Methods Used
Analyzer
Chemical
Method
Principle of Measurement
Analyzer Sequence
Aztec 600
Aluminium
Pyrocatechol
Violet
Based on measurement of the blue colored
complex formed by the reaction between
aluminium and pyrocatechol violet in a
suitably-buffered solution.
Acidification of the sample is normally sufficient
treatment to convert all forms of aluminium to
those that react with the pyrocatechol violet with
the exception of suspended aluminates.
1.
Rinse cell with sample.
2.
Bring in reagent 1 (acid).
3.
Bring in sample.
4.
Wait for 3 minutes (converts Al to a form that reacts).
5.
Measure the background to correct for natural color.
6.
Bring in reagent 2 (adjusts to correct pH).
7.
Bring in reagent 3 (color-forming reagent).
8.
Mix with air.
9.
Wait for 5 minutes to allow color to develop.
10. Measure final color formed, account for background
and output result as a concentration.
Aztec 600
Ammonia
Indophenol Blue Ammonia reacts in a buffered alkaline solution in
the prescence of a catalyst to give
monochloramine. The resulting monochloramine
product then reacts with a phenolic compound,
giving the indophenol blue compound which is
measured spectrophotometrically in the analyzer.
1.
Rinse cell with sample.
2.
Bring in color reagent.
3.
Bring in sample.
4.
Wait 30 seconds.
5.
Measure background absorbance.
6.
Bring in catalyst.
7.
Bring in alkaline buffer.
8.
Mix with air.
9.
Wait 10 minutes for color to develop.
10. Measure final absorbance.
Aztec 600
Color
Absorbance
The absorbance of the sample is measured at
400nm and expressed as a color corresponding
to the Platinum-Cobalt Scale (Pt-Co) or Hazen
Scale.
1.
Rinse cell with sample.
2.
Bring in sample.
3.
Wait 25 seconds.
4.
Measure sample absorbance.
Aztec 600 Iron
TPTZ
Based on the measurement of the blue-purple
colored complex formed by the reaction between
iron and tripyridyl-triazine (TPTZ) in a suitably
buffered solution.
Acidification of the sample is normally sufficient
treatment to convert all forms of iron to those that
react with the TPTZ.
1.
Rinse cell with sample.
2.
Bring in reagent 1 (acid).
3.
Bring in sample.
4.
Wait for 4 minutes (converts Fe to a form that reacts).
5.
Measure the background to correct for natural color.
6.
Bring in reagent 2 (adjusts to correct pH).
7.
Bring in reagent 3 (color-forming reagent).
8.
Mix with air.
9.
Wait for 3 minutes to allow color to develop.
10. Measure final color formed, account for background
and output result as a concentration.
Table C.2 Chemical Measurement Methods Used
