What does a positive nitrate test mean?

An organism may be reported as nitrate-positive if a red color develops in the medium after Nitrate reagents A and B are added to the medium, indicating that the organism has reduced nitrate to nitrite.

How do you read nitrate test results?

If the nitrate broth turns red (tubes pictured in the center) after nitrate I and nitrate II are added, this color indicates a positive result. If instead, the tube turns red (tube pictured on the left) after the addition of Zn, this indicates a negative result.

What does a nitrate test measure?

A nitrate meter is used to measure the concentration of nitrate in water. Nitrate is found naturally in water and is not harmful at low levels. Nitrate testing equipment can be used for measuring nitrate in water, ascertaining the natural level and identifying if there is a pollutant entering the water.

How does a nitrate test work?

The nitrate reduction test is based on the detection of nitrite and its ability to form a red compound when it reacts with sulfanilic acid to form a complex (nitrite-sulfanilic acid) which then reacts with a α-naphthylamine to give a red precipitate (prontosil), which is a water-soluble azo dye.

Is nitrate positive or negative charge?

The nitrate ion, NO−3 , has a SINGLE, FORMAL negative charge.

What does a negative nitrate test look like?

Therefore, another step is needed in the test. Add a small amount of powdered zinc. If the tube turns red after the addition of the zinc, it means that unreduced nitrate was present*. Therefore, the red color on the second step is a negative result.

What is the most common cause of excessive nitrates in waterways?

High levels of nitrate in well water often result from improper well construction, well location, overuse of chemical fertilizers, or improper disposal of human and animal waste.

Why does nitrate have a 3?

When a laboratory reports directly the concentration of nitrate, it is referring specifically to the nitrate ion, which is designated chemically as NO3-. Nitrate is one part nitrogen plus three parts oxygen so nitrogen only makes up about 22.6 percent on the nitrate ion.

Why is the charge on nitrate 1?

The oxygens which have double-bonds have a shared or owned eight electrons, so they are considered neutral. Finally, the single bound oxygen atoms have nine electrons linked with them, and they have a negative charge overall. This means the nitrate ion has an overall charge of -1.

Does nitrates in urine mean infection?

If bacteria enter the urinary tract, nitrates can turn into different, similarly named chemicals called nitrites. Nitrites in urine may be a sign of a urinary tract infection (UTI). UTIs are one of the most common types of infections, especially in women.