ReduktionsGriessbaserade

ReduktionsGriessbaserade is a term used in analytical chemistry to describe a class of nitrate determination methods that combine a reduction step with a Griess-based colorimetric detection. The name reflects two core ideas: a prior reduction to convert nitrate to nitrite, and the subsequent Griess reaction that detects nitrite through a diazotization-coupling reaction forming a pink azo dye measured spectrophotometrically.

Principle and workflow

In reduktionsGriessbaserade assays, a water, soil, or plant extract sample is first treated with a reducing agent to convert all nitrate to nitrite. The produced nitrite then reacts with sulfanilamide under acidic conditions and with N-1-naphthylethylenediamine dihydrochloride (NED) to form a colored azo compound. The intensity of the color, typically read at around 540–550 nm, is proportional to the nitrogen content originally present as nitrate after accounting for the reduction efficiency.

Reagents and configurations

Common reduction methods include chemical reducers such as cadmium or vanadium(III) salts. The reduction step is followed by the standard Griess reagents (sulfanilamide and NED). The approach can be implemented in batch tests or integrated into flow-through or test-strip formats for field use.

Applications, advantages, and limitations

The reduktionsGriessbaserade approach is widely used for environmental monitoring of nitrate levels in drinking water, surface water, and wastewater due to its simplicity and low cost. Limitations include potential interferences from other nitro- or amine-containing compounds, the need for careful calibration, and, in some configurations, the use of toxic reducing agents such as cadmium.

See also

Griess reaction; nitrate reduction; colorimetric nitrite assays.