Nitrate determination in water

The measurement of nitrate (NO₃⁻) in water is an essential analysis for assessing the quality of drinking water, surface water and industrial effluents . Nitrates are nitrogen compounds resulting from the degradation of organic matter , agricultural fertilizers or even industrial waste .

In excess, they can have harmful effects on human health (risk of methemoglobinemia in infants) and on the environment (eutrophication of aquatic environments).
The objective of this analysis is therefore to quantify the nitrate concentration in order to:

• Check compliance with potability and discharge standards (European Directive 98/83/EC, Public Health Code).
• Monitor nitrogen pollution in agricultural and industrial areas.
• Evaluate treatment performance in wastewater treatment plants or filtration systems.

Analytical methods used

Two main techniques are used for the determination of nitrate in water:

• UV spectrophotometry : measurement of nitrate absorbance at a specific wavelength (approximately 220 nm). This rapid method allows direct quantification of the concentration in clear or weakly charged samples.
• Ion chromatography (or ion exchange) : selective separation of anions (nitrates, nitrites, chlorides, sulfates) on an ion exchange column, followed by conductometric detection. This technique offers high sensitivity and allows for the simultaneous analysis of several ions.

These analyses are carried out in accordance with international standards (ISO 7890-1 to 7890-3, NF EN ISO 10304-1), guaranteeing the traceability and reliability of the results .

Affected matrices

Nitrate determination can be carried out on a wide variety of aqueous samples:

• Drinking and distribution water , to guarantee the health safety of consumers.
• Groundwater and surface water (rivers, lakes, water tables) for environmental monitoring.
• Wastewater and industrial water , in order to control discharges from the production site.
• Agricultural effluents , to measure the impact of nitrogen fertilizers.

This analysis is suitable for environmental laboratories, water network operators, local authorities, food industry manufacturers and environmental design offices.

Industrial and regulatory applications

control in water is a major requirement in many sectors:

• Environment and agriculture : assessment of nitrogen contamination and prevention of eutrophication of aquatic environments.
• Food industry : monitoring of water used in production and cleaning processes.
• Water treatment : validation of the performance of filters, ion exchange resins and biological processes.
• Public health : regulatory compliance for drinking water (maximum authorized value: 50 mg/L).

Compliance with these standards guarantees the protection of consumers and aquatic ecosystems , while preventing sanctions linked to regulatory excesses.

Interpretation of results

The results are expressed in mg/L of NO₃⁻ .

• A concentration below 50 mg/L indicates compliance for drinking water.
• Higher values ​​may indicate pollution of agricultural or industrial origin requiring corrective measures.

Additional analyses of pH , conductivity and total organic matter (TOC) can help to better interpret the results and identify the source of contamination.

YesWeLab expertise

YesWeLab provides a network of ISO 17025 and COFRAC accredited partner laboratories , specializing in environmental and physicochemical water analyses .

Thanks to the YesWeLab digital platform , water analysis management is simplified: quote requests, sample tracking and online consultation of test reports.

For complete water quality monitoring, also discover:

• The dosage of ammonium .
• Nitrite dosage .
• The dosage of total phosphorus .

For any specific request, contact our scientific team to design an analysis protocol adapted to your environmental needs.