Spectrophotometric determination of nitrite in water

Abstract

A sensitive and selective colour reaction for the determination of nitrite is presented Nitrite reacts with p-aminophenylmercaptoacetic acid in the presence of hydrochloric acid to form a diazonium cation, which is subsequently coupled with N-(I-naphthy1)ethylenediamine di hydrochloride in acidic medium to form a stable bluish violet azo dye The method IS suitable for the determination of nitrite from 0 02 to 0 80 p p m in a 1 0-cm cuvette The observed molar absorptivity and Sandell's sensitivity of the azo dye are 465 x lo4 I mol-1 cm-1 and 0 001 pg cm-2, respectively The method is free from most interferences The method has been applied to polluted water samples and the results obtained compare favourably with those from standard methods Keywords Spectrophotometry, nitrite determination, p aminophenylmercaptoacetic acid, water, N -( 1 -naph th yl)eth ylenediam r ne dr h ydrochloridePaper Bl00057C

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.…”

Spectrophotometric determination of nitrite by its catalytic effect on the oxidation of congo red with bromate

“…This intermediate is then allowed to react with a coupling reagent, namely naphtyl-1-amine, to form a deep red-colored azo dye. This procedure has been the subject of several modifications [13][14][15][16]. However, many of the modified methods are subjected of several drawbacks (azo dye formation is dependent on pH, diazotization temperature and coupling time; toxicity of certain amines are also an important point for chemists).…”

“…However, many of the modified methods are subjected of several drawbacks (azo dye formation is dependent on pH, diazotization temperature and coupling time; toxicity of certain amines are also an important point for chemists). As examples, the reaction system p-nitroaniline + diphenylamine is time consuming and less sensitive [13]; the system 4-(1-metyl-1-mesitylcyclobutan-3-yl)-2-aminothiazole + N,Ndimethyl aniline is pH-dependent, time consuming and extractive [14]; by using p-nitroaniline + 2-methyl-8-quinolinol, most cations and anions interfered [15]; the reaction system paminophenylmercaptoacetic acid + N- (1-naphthyl)ethylenediamine dihydrochloride is time consuming [16]. Besides, these procedures involve the use of carcinogenic reagents, which makes them outside of the standards of clean chemistry [17].…”

Flow Injection Analysis of Nitrite Based on Spectrophotometric Measurements of Iodine Formed by Oxidation of Iodide with Nitrite

“…2,3 Most of these methods are based upon the different modifications of the Griess reaction; 4 in this process, diazo compounds are formed by diazotization of aromatic amines with nitrite and subsequently the diazonium cations are coupled with aromatic amines or phenol. In addition, various diazotizable amines such as 8-amino-1-hydroxynaphthalene-3,6-disulfonic acid 5 , 4-aminobenzotrifluoride 6 , paminophenylmercaptoacetic acid 7 , p-aminobenzophenone 8,9 , p-nitroaniline 8 , sulfanilic acid 10,12 and paminoacetophenone 10,11,13 have been investigated, and also various coupling agents of naphthalene derivatives [5][6][7][8][9][10][11][12] and resorcinol 13 have been studied. Many of these methods give good sensitivity and/or selectivity.…”