Overview of colorimetric determinations in power plant chemistry

The table below shows a series of analytes that can be determined colorimetrically. Metrohm Process Analytics instruments of the Plug and Analyze, ADI 2019, or ADI 2045 series can be used for the determination.
Analyte Concentration range
[mg/L]
Method (color reagent)
Water hardness (Ca, Mg)
0.005–5
Hydroxynaphthol blue (HNB)
Iron (Fe2+)
0.005–1
Triazine
Copper (Cu2+)
0.02–5
2,2-Bicinchoninic acid
Nickel (Ni2+)
0.02–3
Dimethylglyoxime
Zinc (Zn2+)
0.02–2
Zincon
Phosphate
0.01–7
Phosphomolybdenum blue
Silica
0.005–5 Molybdenum blue
Hydrazine
0.005–0.5
p-Dimethylaminobenzaldehyde
Diethylhydroxylamine (DEHA)
0.005–0.5
Fe3+