Nitrate Test Kits
Visual Kits
| Range | MDL | Method | Type | Test Kit | Refill No. |
|---|---|---|---|---|---|
| 0 - 3.4 ppm as N | 0.3 ppm | Zinc Reduction | CHEMets | K-6905 | R-7002 |
| 0 - 4.5 ppm as N | 0.4 ppm | Cadmium Reduction | CHEMets | K-6904 | R-7002 |
| 0 - 45 ppm as N | 4 ppm | Cadmium Reduction | CHEMets | K-6909D | R-7002 + A-6900 |
| 0 - 225 ppm as N | 20 ppm | Cadmium Reduction | CHEMets | K-6909A | R-7002 + A-6900 |
Photometric Kits
| Range | Method | Type | Test Kit |
|---|---|---|---|
| 0 - 1.50 ppm as N | Zinc Reduction | Vacu-vials | K-6913 |
| 0 - 1.50 ppm as N | Cadmium Reduction | Vacu-vials | K-6903 |
| 0 - 7.50 ppm as N | Cadmium Reduction | Vacu-vials | K-6923 |
| 0 - 50.0 ppm as NO₃ | Cadmium Reduction | Vacu-vials | K-6933 |
CHEMetrics test kits for the determination of Nitrate in aqueous solutions employ the Zinc Reduction method as well as the Cadmium Reduction method to deliver sensitivity and accuracy within minutes. The Zinc Reduction method is cadmium-free, simplifies disposal procedures, and is suitable for drinking and surface waters, industrial wastewater, and seawater testing. The Cadmium Reduction method is suitable for drinking and surface waters as well as domestic and industrial waste. Both methods reduce nitrate to nitrite and measure the nitrite concentration colourimetrically. Based on CHEMetrics patented Self-Filling Reagent Ampoule technology. Premixed. Premeasured. Precise. Both visual and instrumental monochloramine testing kit formats.
CHEMets® visual test kits use colour comparators for analysis. These CHEMets self-filling ampoules that contain pre-measured reagent for a single test. After a simple reduction step, simply snap the ampoule directly in a sample to draw in the correct volume of sample, then compare to the supplied colour standards to determine the concentration.
Vacu-vials® instrumental kits employ the same self-filling ampoule technology and rely on CHEMetrics direct-readout photometers or spectrophotometers capable of accepting a 13-mm diameter round cell. Each kit contains 30 tests. Suitable for potable, surface and seawater as well as industrial wastewater testing.
Zinc Reduction Method
Nitrate is reduced to nitrite using Zinc as the reducing agent. The resulting nitrite concentration is then determined colourimetrically. Nitrate concentrations can also be determined in the presence of low levels of nitrite (by difference). Results are expressed as ppm (mg/l) N (NO3-N).
The benefit of the Zinc Reduction chemistry is that it is resistant to chloride interference, and is suitable for testing seawater and brines; and also does not contain the heavy metal Cadmium, simplifying disposal procedures. This test method is applicable to industrial wastewaters, drinking water, surface waters and seawater. The test kit is based on the patented CHEMetrics Self-Filling Reagent Ampoule technology.
This new visual colourimetric test kit's test method is applicable to industrial wastewaters, drinking, and surface waters, and seawater.
References:
ASTM D 3867-09, Nitrate-Nitrite in Water, Test Method B.
APHA Standard Methods, 22nd ed., Method 4500-NO3- E -2000.
USEPA Methods for Chemical Analysis of Water and Wastes, Method 353.3 (1983).
Nelson, J.L., Kurtz, L.T., and R.H. Bray, Rapid Determination of Nitrates and Nitrites. Anal. Chem., V26, p. 1081-1082, (1954).
Cadmium Reduction Method
Nitrate is reduced to nitrite using cadmium as the reducing agent. The resulting nitrite concentration is then determined colourimetrically. This method is applicable to drinking and surface waters, as well as domestic and industrial wastes. Nitrite will interfere with this test. Results are expressed as ppm (mg/l) NO3-N or NO3.
References:
ASTM D 3867-09, Nitrate-Nitrite in Water, Test Method B.
APHA Standard Methods, 22nd ed., Method 4500-NO3- E -2000.
USEPA Methods for Chemical Analysis of Water and Wastes, Method 353.3 (1983).
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Technical Data Sheet |
Applications
Nitrates are used in many industries, but the most common use is in agricultural fertilisers. Several million tonnes of nitrates are manufactured annually for this purpose. Explosives are another common application.
The majority of nitrate found in surface water, groundwater and drinking water in the UK derives from diffuse pollution from inorganic, chemical fertilisers from farmland runoff, the remainder being from sewage sludge disposal to land, atmospheric pollution and point sources. Rainfall absorbs nitrate out of inorganic fertiliser-treated soil and the runoff can contaminate surrounding water sources, such as streams, rivers and lakes. Nitrates may also seep through certain soil types and find their way into groundwater.
Nitrate levels have increased post-WW2 because of intensified agricultural activities including ploughing of grassland and increase fertiliser usage. Groundwater nitrate concentrations steadily increased between 1985 and 2002 according to the British Geological Survey.
Excessive nitrate levels in natural waters, such as over 40 ppm (mg/l), may be toxic to aquatic insects or fish and can cause algal blooms. Elevated levels in drinking water may be carcinogenic and can cause methaemoglobinaemia in infants. The Directive Prescribed Concentration or Value (PCV) for free Nitrate in drinking water in the UK and Ireland is 50 mg/l (ppm) as NO3 (11.3 ppm as N). This is the same as the WHO's guideline value. A Maximum Contaminant Level of 10 ppm as N has been established for drinking water by the USEPA.
Since fertiliser is so widely used, it is very common for environmental groups to monitor nitrate in water bodies to assess the health of aquatic ecosystems. Wastewater and drinking water facilities also test for nitrate to stay within discharge limits and keep drinking water safe.
What is Nitrate?
Nitrate (NO3–) is a polyatomic anion containing nitrogen and oxygen. It is the most completely oxidised form of nitrogen and is a key component of the nitrogen cycle. Any salt containing the NO3– ion can be referred to as a nitrate. Nitrate is the conjugate base of nitric acid. Most inorganic nitrates are water soluble. Nitrate is formed during the final stages of biological decomposition in the nitrogen cycle, where nitrifying bacteria convert nitrites to nitrates. This occurs in the same way in both wastewater treatment facilities and natural water supplies. Nitrate is bioavailable and is the primary source of nitrogen for plants. Nitrate is a naturally occurring ion and can be found in surface water, groundwater and soil at low concentrations, usually less than 2.2 ppm (mg/l) NO3.