EM Quant® Nitrite Test, Catalog No. 10007
Test strips for the detection and
semi-quantitative determination of nitrite ions
Nitrite indicates pollution. The EM Quant®
Nitrite Test thus plays an important role in the analysis of drinking
water, industrial water, effluent and aquarium water.
Nitrite determination is an important aspect of
food analysis and is applied in the testing of meat products, pickling
salt, brine and deep frozen spinach. The test can also be used for the
rapid analysis of skimmed milk, whey and powdered milk.
Aquarium water should be tested for nitrite at
regular intervals, as fish may be poisoned by concentrations exceeding
1mg/l (ppm), depending on species and duration of exposure. In
bacteriology, the EM Quantâ Nitrite Test helps simplify the
bacteriological nitrate reduction test.
The test kit may also be used for measuring
oxides of nitrogen in air.
Principle of the Method
Any nitrite contained in the test solution (the
pH of which may be anywhere between 1 and 13) is converted to nitrous
acid in the presence of an acid buffer. The nitrous acid diazolizes an
aromatic amine and yields a diazonium salt, which couples with
N-(1-naphthyl)ethylenediamine to produce a red-violet azo dye.
0 - 1 - 5 - 10 - 20 - 40 - 80mg/l (PPM) NO2.
- Remove a test strip and close the container
- Immerse the test strip in the sample
solution for 1 second, so that the reaction zone is thoroughly
- Remove the test strip,gently shake off
excess liquid, wait 15 seconds and compare the reaction zone with
the color scale.
Strongly acidic solutions (pH <1) must be
buffered to pH approximately 3-5 with sodium acetate; strongly
alkaline solutions (pH >13) with tartaric acid. If the nitrite
concentration is higher than 80mg/l, either dilute the sample or use
10022 EM Quant® Nitrite Test (measuring range 0.1-3g/l).
10 mg NO2 is equivalent to 3 mg N.
Determination in Meat Products
Finely mince at least 10g of meat product
several times in quick succession. Add 8ml of 1 N sodium acetate
solution (13.6g sodium acetate dissolved in 100ml of distilled
water) to 5g of the minced sample and homogenize for approximately 1
minute in a food blender or Ultra-Turrax stirrer. Filter through a
soft fluted filter (pressinggently if necessary), collect in a short
test tube and test for nitrite in the filtrate as directed on the
Determination in Sausage Meat
Either use the method described above or follow
the following simpler procedure:
Use a mortar and pestle togrind 2g of finely
chopped sausage for approximately 2 minutes with 5g of sea sand and 8ml of 1 N sodium acetate solution (see above). Then filter through a
soft fluted filter (pressinggently if necessary), collect in a test
tube or flask and test for nitrite as directed on the pack.
The Nitrate Reductase Test for Meat and Meat Products
The time required to reduce nitrate is a
function of the quantity of reductases and thus also of the number of
nitrate-reducing microorganisms (especially Enterobacteriaceae)
present in slurries and homogenized specimens.
To the slurried or homogenized meat add
sufficient nitrate togive a final concentration of 0.06% then
incubate at 30·C. Check for nitrate formation with a Nitrite Test
strip at hourly intervals.
Determination in Nitrite Pickling Salt
Place 4g of nitrite pickling salt into a clean
container with a capacity of approximately 2 liters. Add a small
volume of water and swirl to dissolve the salt. Make up with water to
a final volume of 1.5 liters and mix thoroughly. Briefly dip a nitrite
strip in this solution, shake off any surplus water, wait 15 seconds
and compare with color scale.
If a value of 10mg/l is indicated, the pickling
salt is satisfactory. It is unsatisfactory if the result is much
higher or lower than this figure and must on no account be used if the
nitrite content is too high.
Influence of Anions
The determination is not disturbed by less than
Cl, ClO3, ClO4,
CN, F, I, Mo7O246,
OCN, PO43, SO42,
acetate, ascorbate, citrate, oxalate, succinate or tartrate.
In the presence of more than 100mg/l [Fe(CN)6]4
, 25mg/l S2, 100mg/l SCN, 500mg/l SO32, 250mg/l S2O32
, 100mg/l S2O42 or 250mg/l
S2O52 the nitrite
concentration indicated is less than that actually present. This
effect is even more pronounced at pH values of less than 6.
Influence of Cations
The determination is not disturbed by less than
||Ag+, Al3+, As3+,
Ba2+, Be2+, Cd2+, Co2+,
Cr3+, Cu2+, Fe2+, Hg+,
Hg2+, K+, Li+, Mg2+,
Mn2+, Na+, Ni2+, Pb2+,
Rb+, Sb3+, Sn2+,Ti4+,
Tl+, VO2+, Zn2+ or Zr4+.
Special note: agray to brown discoloration of
the reaction zone indicates the presence of oxidizing ions e.g. more
than 10mg/l CrO42, 25mg/l [Fe(CN)6]3,
250mg/l IO3, 500mg/l IO4,
5mg/l MnO4, 100mg/l S2O82,
10mg/l VO3, 25mg/l Au3+,
25mg/l Ce4+ or 100mg/l Fe3+. Nitrate is
unstable in the presence of these ions.
19899 Nitrate standard solution, 500ml.
10007 EM Quant® Pack of Nitrite
Test 100 test strips