Nitrite Test Paper


Nitrite Products | CTL Scientific Supply

Nitrite

Precise rapid tests for water and waste water samples

Nitrite is produced as an intermediate in the nitrification in sewage treatment plants. An excessive content of nitrite indicates that the plant’s biology does not work optimally. A high level of nitrite in cooling lubricants indicates a microbiological contamination of the circuit. Nitrite has to be controlled in aquariums as well in order to ensure optimum living conditions for the aquatic life.

Nitrite ions are present in low concentrations in surface waters and rarely in groundwaters. In wastewaters, by contrast, nitrite concentrations are often higher. Nitrite ions are present in water almost exclusively in dissolved form. Higher nitrite concentrations in wastewaters suggest either industrial effluents (metal pickling agents, chemical industry) or fecal contamination (decomposition product of nitrification: nitrite is produced during the bacterial oxidation of ammonia and in the reduction of nitrate).

Our Nitrite Products

Product Range REF Order
Potassium iodide starch paper without adhesive dot 2 mg/L NO2- P-100
box of 200 strips (20 x 70 mm) $24.70  
Potassium iodide starch paper with adhesive dot 2 mg/L NO2- P-100A
box of 100 strips (20 x 70 mm) $31.40  
Potassium iodide starch paper 1 mg/L Cl2
3 mg/L NO2-		 90756
booklet of 100 $11.50  
Potassium iodide starch paper MN 816 N standard grade - Standard Sensitivity 1 mg/L Cl2
1 mg/L NO2-		 90754
roll of 5 meter length $14.30  
Potassium iodide starch paper MN 616 T recommended for spot tests - Medium Sensitivity 1 mg/L Cl2
4 mg/L NO2-		 90758
box of 200 strips $24.70  
Potassium iodide starch paper MN 260 HE highly sensitive paper - High Sensitivity 1 mg/L Cl2
1 mg/L NO2-		 90757
box of 200 strips $25.10  
Nitratesmo > 10 mg/L NO3-
> 5 mg/L NO2-		 90611
roll of 5 meter length $69.10  
NANOCOLOR® Nitrite 2 0.003 – 0.460 mg/L NO2‑N 985068
1 pack (20 test tubes) $39.00  
NANOCOLOR® Nitrite 4 0.1 – 4.0 mg/L NO2‑N 985069
1 pack (20 test tubes) $39.00  
QUANTOFIX® Nitrite 0 · 1 · 5 · 10 · 20 · 40 · 80 mg/L NO2- 91311
box of 100 strips $38.90  
QUANTOFIX® Nitrite 3000 0 · 0.1 · 0.3 · 0.6 · 1 · 2 · 3 g/L NO2- 91322
box of 100 strips $39.10  
QUANTOFIX® Nitrite / pH Nitrite: 0 · 1 · 5 · 10 · 20 · 40 · 80 mg/L NO2-
pH: 6.0 · 6.4 · 6.7 · 7.0 · 7.3 · 7.6 · 7.9 · 8.2 · 8.4 · 8.6 · 8.8 · 9.0 · 9.3 · 9.6		 91338
box of 100 $50.50  
QUANTOFIX® Nitrite / pH 2 Nitrite: 0 · 1 · 5 · 10 · 20 · 40 · 80 · 100 mg/L NO2-
pH: 8.0 · 8.2 · 8.4 · 8.6 · 8.8 · 9.0 · 9.2 · 9.4 · 9.6 · 9.8 · 10.0		 91364
box of 100 strips $54.60  
QUANTOFIX® Nitrate / Nitrite Nitrate: 0 · 10 · 25 · 50 · 100 · 250 · 500 mg/L NO3-
Nitrite: 0 · 1 · 5 · 10 · 20 · 40 · 80 mg/L NO2-		 91313
box of 100 strips $42.90  
VISOCOLOR® ECO Nitrite 0 · 0.02 · 0.03 · 0.05 · 0.07 · 0.1 · 0.2 · 0.3 · 0.5 mg/L NO2- 931044
1 kit (~120 tests) $67.95  
VISOCOLOR® Nitrite Powder Pillows 0.01 – 0.30 mg/L NO2‑N 936230
100 POWDER PILLOWS $54.10  

General information

Another source of nitrite formation from nitrate are of galvanized iron pipes of domestic installations. Concentrations up to 1 mg/L are still classified as harmless. A major field of application of nitrites is the manufacture of dyes. In adults, reduction of nitrate to nitrite takes place in the small intestine, whereas in infants this occurs already in the stomach. Nitrites are toxic to humans. They block the blood pigment hemoglobin, which is necessary for oxygen transport. Especially in infants, life-threatening conditions with acute suffocation may occur (infant cyanosis = methemoglobinaemia). In addition, nitrites are also involved in the formation of carcinogenic nitrosamines.

Despite their toxicity, nitrites have numerous applications. They are used e.g. as food additives or in the production of sausages as nitrite curing salt. In general, an increase in nitrite content is always a sign of bacterial contamination. These can be detected early by a nitrite measurement, which is also an important parameter in cooling lubricants. Nitrites react with cooling lubricants to form carcinogenic nitrosamines, which can enter the human body as aerosols.

NO2-N is frequently used as notation rather than NO2-, which indicates that only the mass of nitrogen of the nitrite ion is taken for account while the oxygen atoms are neglected. The conversion factor of NO2-N to NO2- is 3.28, resulting from the atomic masses.

mg/L NO2- mg/L NO2-N
0.02 0.006
0.05 0.015
0.1 0.03
0.2 0.06
0.5 0.15

Did you know?

Nitrites are toxic since they block the blood pigment hemoglobin and thus the transport of oxygen.

Did you know?

Nitrites have high and pH-dependent toxicity to fish.

Reaction basis

Depending on the product range (VISOCOLOR® or NANOCOLOR®) and test kit, one of two different reactions is underlying:

(a) ISO method in analogy to ISO 6777: Nitrite reacts with sulfanilamide and N-(1-naphthyl)-ethylenediamine to form a purple azo dye. The underlying reaction is analogous to DIN EN 26777-D10, APHA 4500-NH2 and EPA 354.1.

nitrite figure A

(b) Sulfanilic acid method (Griess-Ilosvay reaction): Sulfanilic acid is diazotized by nitrite in acidic solution. The diazonium salt which is formed is then coupled with 1-naphthylamine to form a red azo dye.

nitrite figure B

Sample preservation

By adjusting the pH to 1-2 with sulfuric acid, the sample can be stored for up to 7 days (storage vessel: PE bottle). Ideally, storage and transport are carried out at 4 °C in the dark.

Tips & tricks

  • Common sources of error
    • Insufficient dissolution of the reagents causes the risk of findings below the actual value.
  • Background information
    • The reagents for sample preparation by clarification precipitation (REF 918937) can be used for removal of emulsions, turbidity and color prior to the nitrite determination, e.g. in cooling lubricants, landfill leachate, etc.
    • Additionally a blank value should be measured for nitrite measurements in heavily contaminated samples (e.g. in inlet waters).
  • Sea water suitability
    • All VISOCOLOR® and NANOCOLOR® nitrite tests are suitable for seawater analysis.
  • pH
    • The pH values for the sample solution stated in the instruction leaflet must be complied with. If necessary, adjust the pH with hydrochloric acid or sodium hydroxide.
  • Interferences
    • Organic colloids, chlorine, humic acids and colored heavy metal ions interfere. Further interfering ions are listed in the instruction leaflets.
  • Turbidity
    • Turbid samples have to be filtered; turbidity leads to incorrect results: For coarsely dispersed turbidities, use qualitative filter paper (e.g. MN 615), for moderately dispersed turbidities, use glass-fiber paper (e.g. MN 85/70 BF) or or membrane filtration set GF/PET 0.45 μm, for finely dispersed turbidities, use membrane filtration kit 0.45 μm or GF/PET 0.45 μm.
Nitrite Extra Picture