Nitrate spectrophotometric determination

Spectrophotometric determinations - continued D. or concn. of potassium nitrate, 710 D. of simultaneous, chromium and manganese, 712... 

Chen used a second-derivative spectrophotometric method for the determination of miconazole nitrate in Pikangshuang [22]. Sample of miconazole nitrate was dissolved in anhydrous ethanol and the second-derivative spectrum of the resulting solution was recorded from 200 300 nm miconazole nitrate was determined by measuring the amplitude value between the peak at 233 nm and the trough at 228 nm. The recovery was 99.8% with a relative standard deviation (n = 6) of 0.2%. 

Mullin, J. B., and J. P. Riley, The Spectrophotometric Determination of Nitrate in Natural Waters with Particulate Reference to Sea Water, Anal. Chim. Acta, 12, 464-480 (1955). 

This method is used for detg the 2-NDPhA content of newly manufd proplnts contg no nitrate esters other than cellulose nitrate. It is not described here because instrumentation required for this test is too expensive and needs special training not acquired by an ordinary chemist Method 218.4-1- Spectrophotometric Determination. This method is used for detg the 2-NDPhA content in newly manufd proplnts. 

Keay and Menage [13] have described an automated method for the determination of ammonium and nitrate in 2 M potassium chloride extracts of soil. In this method, a sample of soil (2 g) is shaken for one hour with 2 M potassium chloride (20 ml) and the filtrate is diluted, in the AutoAnalyser, with a 0.25% suspension of magnesium oxide the ammonia evolved is absorbed in 0.1 M hydrochloric acid and determined spectrophotometrically at 625 nm by the indophenol method. The sum of ammonium plus nitrate is determined similarly, but with addition of 4.5% titanous chloride solution before distillation this reduces nitrate but not nitrite. 

Solid-phase extraction of various analyte complexes on e.g. microcrystalline naphthalene (Ni [23] and Cu [24] with nitroso-R salt and tetradecyldimethylbenzylammonium chloride), ammonium tetraphenylborate-naphthalene (U with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol) [25], chitin column (Cr(VI) with 1,5-diphenylcarbazide) [26], strong anion-exchange cartridge (Cr(VI) at pH 8) [27], Cig cartridge (CL-azo dye) [28] and minicolumn (As with ammonium diethyl dithiophosphate) [29], silica modified chemically with A-allyl- or A-phenyl-TV -propylthiourea (OSO4) [30] and Sephadex DEAE A-25 (chloride form) (V with Eriochrome Cyanine R) [31] prior to the spectrophotometric determination has recently been reported. The application of solid-phase spectrophotometry to determine nitrite and nitrate in water samples has recently been described [32]. 

Nitrogen dioxide in air and nitrate and/or nitrite in water, soil, analytical-grade KBr, potassium sulfate, ammonium sulfate, potassium nitrate and ammonium nitrate and toothpaste were determined by means of the decrease in absorbance of Neutral Red caused by diazotization with nitrite from the sample [4]. A mixture of oxalic acid, p-aminoacetophenone and Al-1-naphthyl ethylenediamine has been proposed as an efficient absorbing system for in situ spectrophotometric determination of nitrogen dioxide in environmental samples [5]. 

Sandwich techniques can also be implemented in a sequential injection analyser, as demonstrated by the spectrophotometric determination of nitrate and nitrite in natural waters [12]. The sample plug was set between two reagent plugs and the assembly was aspirated towards the holding coil of an ordinary sequential injection analyser. Two Griess reaction zones were established at both ends of the sample zone, and only one was... 

M.F. Gine, B.F. Reis, E.A.G. Zagatto, F.J. Krug, A.O. Jacintho, A simple procedure for standard additions in flow injection analysis. Spectrophotometric determination of nitrate in plant extracts, Anal. Chim. Acta 155 (1983) 131. 

Nitrite. This chemical species, formed in-line by passing a potassium nitrate stream through a copperised cadmium solid-phase reactor, was used in the spectrophotometric determination of sulfadiazine in pharmaceutical formulations [99]. A nitrite solution that would normally be stored in a refrigerator, standardised and frequently replaced was therefore not required. 

The spectrophotometric determination of Fe(II), Fe(III), nitrate and nitrite ions in natural and wastewaters in a sequential injection system [298] is an interesting example of this innovation. In-line tangential filtration was performed prior to the sample insertion port as part of the sampling step. Particulate material was not aspirated towards the holding coil and several samples could be analysed without the need for frequent cleaning of the filtration unit. Analytical figures of merit were similar to those for the corresponding flow-based analytical procedure with manual sample filtration prior to flow analysis. 

Ensafi, A. A., Rezaei, B. and Nouroozi, S. (2004) Simultaneous spectrophotometric determination of nitrite and nitrate by flow injection analysis. Anal Sci, 20 (12), 1749-1753. 

The standard methods of water analyses used in various countries employ other agents for direct spectrophotometric determination of nitrates, for example, chromotropic acid (4,5-dihydroxy-naphthalene-2,7-disulphonic acid) [13] or 2,6-dimethylphenol and p-fluorophenol [49]. As well the method with salicylate the method with chromotropic acid is also used in the standard methods. 

L. Andersson, Simultaneous Spectrophotometric Determination of Nitrite and Nitrate by Flow Injection Analysis. AnaL Chim. Acta, 110 (1979) 123. 

S. Xu and Z. Fang, Sinultaneous Spectrophotometric Determination of Nitrate and Nitrite in Water and Soil Extracts by Flow Injection Analysis [in Chinese]. Fenxi Huaxue, 11 (1983) 93. 

Spectrophotometric determination of CV in the W phase showed that CV " almost completely remained in the NB phase. Potentiometric titration with a standard silver nitrate solution showed that a part (0.7-18%) of CP initially added to the NB phase remained unexchanged with RCO2 in the W phase. The equilibrium concentration of RCO2 in NB was evaluated from its initial concentration and the concentration of CP remaining in NB. Such distribution behavior of the ions in the NB-W system could be elucidated by using the above-mentioned theory [30-32], in which the standard ion-transfer potential A ) is used as a measure of extractability of an individual ion. It could be thus concluded that, in this system, the ions are distributed individually without forming ion pairs. 

Nitrate may also be determined by LC with an anion-exchange column. A comparison has been made between the traditional method of nitrate determination using a reducing cadmium column and spectrophotometric determination with a reversed-phase LC method with orthophosphoric acid adjusted to pH 3.5 with sodium hydroxide as the mobile phase. A high correlation was observed between the nitrate content determined by the two methods. However, LC was found to be more precise, reproducible, and appropriate for routine work. 

With regards to spectrophotometric titrimetry, the chloride (hydrochloride) content in a drug can be determined by titration with mercuric nitrate, using a diphenylcarbazone-Bromothymol Blue mixture as indicator. For its spectrophotometric determination, a solution of the Hg(II)-diphenyl-carbazone complex is titrated with the unknown sample (pharmaceutical formulation) and the absorbance of the resulting complex at 540 nm - which is decreased as a result of the diphenylcarbazone being displaced by the chloride present in the sample - is monitored. 

Nitrogen-containing species The nitrate content in waters is usually low but can rise to appreciable levels in farming wastewater as a result of soil fertilization. Nitrite originates from the microbiological reduction of nitrate or the oxidation of ammonia. Nitrite is usually determined spectrophotometrically using the Griess reaction. Nitrate is determined by the same method after prereduction to nitrite. 

The inline conversion of nitrate to nitrite and subsequent spectrophotometric determination after diazotization and coupling reactions is the basis of an important set of analytical methods for the simultaneous determination of both ions. Either homogeneous (titanium(III) chloride, hydrazinium sulfate, etc.) or heterogeneous (zinc, cadmium, amalgamated cadmium, copperized cadmium, etc.) reduction agents, photochemical or enzymatic reactions have been used [157]. The nitrite so produced is determined through spectrophotometric detection of the reddish purple azo dye formed as a result of the modihed Griess chemistry. 

LA. Tsoulfanidis, G.Z. Tsogas, D.L. Giokas, A.G. Vlessidis, Design of a field flow system for the on-line spectrophotometric determination of phosphate, nitrite and nitrate in natural water and wastewater, Microchim. Acta 160 (2008) 461 169. 

A. Kazemzadeh, A.A. Ensafi, Sequential flow injection spectrophotometric determination of nitrite and nitrate in various samples. Anal. Chim. Acta 442 (2001) 319-326. 

Absorption spectrophotometric analysis procedures have been developed for a number of environmental species. For water contaminants alone, these include procedures for the determination of arsenic, boron, bromide ion, cyanide, fluoride, nitrate, phenols, phosphate, selenium, sUica, sulfide, surfactants, and tannin and lignin. A typical such procedure is the spectrophotometric determination of phenol in water by the reaction with 4-aminoantipyrene... 

Most spectrophotometric methods consist of colorimetric detection of nitrite at 520-540 nm, based on the classical reaction with N-(l-naphthyl)ethylenediamine and sulfanilamide (Griess reaction). Nitrate is determined colorimetrically in the same way after reduction to nitrite by means of a cadmium column (ISO Standard 14673-1 2004/ IDF Standard 189-1 2004). Different SIA systems based on the Griess reaction have been developed for the determination of nitrate and nitrite in infant formulas and milk powder, in dairy samples, in cured meat and infant formulas and milk powder (Oliveira et al., 2004, 2007 Reis Lima et al., 2006 Piston et al., 2011). 

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