Study of interferences in the spectrophotometric determination of nitrite using composite diazotisation-coupling reagents

Abstract

A study was made of 82 possible interferences in the spectrophotometric determination of nitrite by the diazotizationcoupling technique using three composite reagents [sulphanilamide and N-( 1 -naphthy1)ethylenediamine (NED); sulphanilic acid and NED; and 4-nitroaniline and NED]. The effects of interferences when using these three reagents differ considerably in many instances. Large amounts of inert salts, such as alkali metal and ammonium sulphates, chlorides and nitrates cause high results with sulphanilic acid -NED reagent and high or low results with sulphanilamide -NED and 4-nitroaniline -NED reagents owing to the Bronsted salt effect. Carbonate, hydrogen carbonate, phosphate, pyrophosphate, tetraborate, acetate, tartrate and oxalate salts can interfere by changing the acidity of the solution or by their buffering action. This interference is less with the 4-nitroaniline -NED method than the other two methods. Silver, mercury(l), bismuth, antimony, lead, barium, strontium and calcium can interfere by precipitating as chloride, oxychloride, oxysulphate or sulphate. Chromium(lll), nickel and cobalt interfere by reason of the colour of their ions.Oxidising and reducing agents usually produce low results. Aluminium, manganese, zinc, cadmium, tin(lV) mercury(ll), titanium(lV), zirconium(lV), iron(lll), copper(ll), molybdenum(Vl), tungsten(Vl1, arsenic(Vl), uranium(Vl), thallium(l), gold(lll), platinum(lV), selenium(lV), bromide, iodide, thiocyanate, cyanide, cyanate, hexacyanoferrate(lI1) and -(ll), fluoride, perchlorate and silicate can interfere in diverse ways.

Flow-injection chemiluminescent determination of nitrite in water based on the formation of peroxynitrite from the reaction of nitrite and hydrogen peroxide

“…spectrophotometric [5][6][7][8], electrochemical [9][10][11][12] and fluorometric [13][14][15] methods. The commonly spectrophotometric determinations of nitrite are based on the diazo coupling reaction.…”

Spectrophotometric determination of nitrite in foodstuffs by flow injection analysis

“…The most promising method for the determination of nitrite seems to be a modified version [16][17][18][19][20][21][22][23] of the Shinn [24] reaction which is based on the well known Gries reaction. This is the reaction of nitrite with a primary aromatic amine to form a diazonium salt, which is then coupled with another aromatic compound to form an azo dye of which the absorbance is measured.…”

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory-Evaluation of alkaline persulfate digestion as an alternative to Kjeldahl digestion for determination of total and dissolved nitrogen and phosphorus in water

“…For specific details of inorganic and organic compounds that might interfere in the color reaction, see Norwitz andKeliher (1985, 1986), as well as more general information by the American Public Health Association (1998a).…”