The settings

Principle of the method

Method reference

${\text{NH}}_{\text{4}}^{+}$

Formation in an alkaline medium of an indophenol type compound by reaction of ${\text{NH}}_{\text{4}}^{+}$ ions with phenol and ${\text{ClO}}^{-}$ in the presence of nitroprusside Na₂[Fe(CN)₅NO]∙2H₂O as catalyst gives a blue indophenol coloring. spectrophotometric measurement at λ = 630 nm

NFT90-015-2

${\text{NO}}_{\text{2}}^{-}$

The method is based on the reaction of ${\text{NO}}_{\text{2}}^{-}$ ions with 4-aminobenzene sulfonamide at pH = 1.9 in the presence of H₃PO₄ to form a diazo salt which complexes with N-(1-Naphthyl)diamino-Dichlorohydrate. 1,2-ethane to give a pink color whose intensity is proportional to the ${\text{NO}}_{\text{2}}^{-}$ content and measurable at 540 nm

NF EN 26777

${\text{NO}}_{\text{3}}^{-}$

The nitrate content is obtained by the sodium salicylate method

AFNOR T90-012

Total Kjeldahl nitrogen

The total nitrogen content (NT) was determined by mineralization in a sulfuric medium in the presence of copper II

ISO 7150/1

${\text{NO}}_{\text{2}}^{-}$

Nitrite content by the Zambelli method

AFNOR (T90-013)

Ion ${\text{PO}}_{\text{4}}^{\text{3}-}$

The reaction of phosphate ions with an acidic solution containing molybdate and antimony ions to form an antimonyl-phosphomolybdate complex which is reduced by ascorbic acid to the brightly colored molybdenum blue spectrometer measurable at 700 nm.

NF EN ISO 6878

Total P

The reaction of H₃PO₄ ions with an acidic solution containing molybdate and antimony ions formation of an antimonyl-phosphomolybdate complex reduced by ascorbic acid to brightly colored molybdenum blue measurable at 700 nm.

NF EN ISO 6878 (T90-023)

COD

Oxidation in an acidic medium of organic matter by excess K₂Cr₂O₇ in the presence of AgSO₄ as catalyst and HgSO₄ to complex the Cl⁻ ions and determination of the excess oxidant with a Mohr’s salt solution (NH₄Fe(SO₄)₂∙6H₂O )

NF T90-101

BOD5

Oxidation of biodegradable organic matter contained in a water sample by natural microorganisms in the dark in amber vials saturated with O₂ placed in a thermostatic incubator at 20˚C ± 2˚C for 5 days

NF EN 1899-2