• Drinking water
  • Process optimisation of wastewater treatment plants
  • Industrial and municipal wastewater
  • Mineral water monitoring
  • Surface water


The determination ranges of the nitrite analyzer vary from trace μg/L to 125 mg/L NO2 using the (optional) internal dilution module. The result can be expressed as NO2 or N-NO2.


In acidic media, nitrites react with sulfanilamide and N-(1-naphthyl)-ethylene diammonium dichloride, forming a purple colored dye. The absorbance intensity is proportional to the nitrites concentration in the sample and is determined at 525 nm.


(Ø 26 mm)
500 ppb N-NO2 (1.6 ppm NO2)
(Ø 16 mm)
1 ppm N-NO2 / (3.2 ppm NO2)
(with dilution)
40 ppm N-NO2 / 125 ppm NO2
Wavelength 525 nm
Number of reagents 2
Min. analysis time 6 minutes

Technical Specifications

Model 3S-CL
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,24 VDC
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)