Nitrates, nitrites, NO2+3



  • Drinking water
  • Process optimisation of wastewater treatment plants
  • Industrial and municipal wastewater
  • Mineral water monitoring
  • Surface water
Nitrates, nitrites, NO<sub>2+3</sub>


Spectrophotometric analyzer for the determination of the nitrate ion in water. The UVNO3 analyzer rely on the measuring principle of UV light absorption of the chromophores NO3-/NO2-. The measurement is the weighted sum of the nitrate and nitrite concentration. As the concentration of NO3- or NO2- increases, UV absorption also increases. In many most applications the NO2- concentration is negligible and this is reason why it's usually considered NO3- measurement. Results are reported on the touchscreen display in mg/L or ppm of NO3 , NO2+3 , NO3-N or NO2+3-N. The measuring, calibration and cleaning frequency can be programmed by the user.
Nitrates are dangerous pollutants for aquatic life and poses risks to human health when present in drinking water. The nitrates concentration in surface waters derive mainly from biological pollution due to urban agglomerations, agriculture nitrogenous fertilizers, discharges from chemical industries and combustion processes. The instrument is ideal for potable water or suface water analysis and with the addition of a dilution module is also capable of the determination of nitrates in complex matrices such as urban and industrial wastewaters.


The method is based on the absorbance that the nitrate ion in water sample presents in the UV region at 220 nm . Considering that also organic substances absorb in that spectrum region, a reference absorption measurement at 270 nm is required, in order to reduce the organic interference. The compensated absorbance is proportional to the nitrate ions concentration in the sample.


Measured parameter NO3-
Wavelength 220 nm
Demineralized water Not required
Min. analysis time 1 minutes

Reagents and standards

Technical Specifications

Model 3S-UVNO3
Sampling Mode Batch, with freely settable frequency.
Sample Pressure: Atmospheric
Temperature: 5 ‐ 45°C (41 ‐ 113°F)
Flow Rate: 80 to 500 mL/min
Connection: 6 mm (¼-in.)
Drain Pressure-free drain
Connection: 12 mm (½-in.)
Input Streams 2
Material Epoxy-coated stainless steel AISI 304
Dimensions (H x W x D) 604 x 380 x 210 mm (23.6 x 14.8 x 8.2 in)
Weight 20 kg (44 lbs)
Power Supply Input Voltage: 115 VAC,230 VAC
Power consumption: max. 80 W
Output signals 2 x 4-20 mA analog outputs
Modbus via RS485,Ethernet
Alarms 2 SPDT programmable voltage-free relays
Digital Input None, Online, Start Extra, Skip Idle, Emergency Stop
Ambient Temperature 5 - 45 °C (41 - 113 °F)
Ambient Humidity 10 - 90 % RH (non-condensing)
Protection Grade IP54 (indoor only, outdoor use possible with external cabinet, not included)