TROPIC MARIN - NP-Standard - NO3 and PO4 reference solution

Reference mineral solution for test kits (NO ₃ , PO ₄ )

Over time, test kit reagents may lose potency due to unfavorable storage conditions, high or low temperatures, and contact with oxygen. Therefore, the tests must be checked regularly on the basis of a stable standard.

Tropic Marin ^® NP-Standard is composed of a laboratory solution whose concentration of nitrates and phosphates is known. It allows you to quickly check the proper functioning of the test kits for nitrates and phosphates. A correction factor can then be calculated.

Advantages :

Manual :

Checking the functioning of the reagents

You need reverse osmosis or demineralised water for this purpose. Fill the cuvette with the required amount of deionized water (according to your test instructions for use). Place the blue tip on the 1ml syringe provided and withdraw from the Tropic Marin ® NP-Standard bottle the following quantity depending on the type of test and the size of the sample:

Add this amount to the water sample. Perform the desired measurement with your test

and set the measurement value M .

The target value S after addition of the standard is 2 mg/l nitrate or approx. 0.2mg/l
of phosphates. If the measured value M corresponds to the set value S , then the test is still fully functional. If the measured value M differs by more than 50-75% from the set value S , then we recommend that you no longer use your test – the reagents have probably lost their effectiveness.
Calculation of the correction factor K
If the deviation is less than 50-75%, you can use the following formula to calculate a factor
of correction K :

K=S/M

Example using a nitrate measurement:

Amount of standard = 0.39ml for a 15ml reverse osmosis water sample

Setpoint S = 2 mg/l

Measured value M = 1.5 mg/l

The measured value M does not correspond to the expected target value S (2 mg/l).

Calculation of the correction factor:

[Pour une meilleure illustration, nous renonçons aux unités des valeurs (mg/l)]

Correction factor K = S / M

K = 2 / 1.5

K = 1.33

Using the correction factor:

Multiply your measured values in the future with the correction factor K, to get the correct value W.

The correction factor K applied to the measurement value M in our example:

Actual value W = M x K

W = 1.5mg/lx 1.33

W = 2mg/l

2 mg/l corresponds to the set value; it is thus demonstrated that the correction factor is correct. Use the correction factor for future measurements of your test kits.

Regularly repeat the control of your test kits, for example, every 2 to 4 weeks.

Other recommended products

To verify mineral testing, we recommend using Tropic Marin ® Multi-Standard.

Tropic Marin ® offers a wide range of highly accurate test kits.