Nitrilotriacetic acid determination

Chromiain(ii) Complexes.—The oxidation of chromium(ii) in alkaline solution has been studied polarographically and the reaction shown to be irreversible with = — 1.65 V vs. S.C.E. In the presence of nitrilotriacetic acid, salicylate, ethylenediamine, and edta the values were determined as —1.075, —1.33, — 1.38, and —1.48 V, respectively. The production of [Cr(edta)NO] from [Cr (edta)H20] and NO, NOJ, or NO2 suggests that this complex is able to react via an inner-sphere mechanism in its redox reactions. ... 

Electroreduction of Cd(II)-nitrilotriace-tic acid and Cd(II)-aspartic acid systems was studied on DME using SWV [73]. The CE mechanism in which the chemical reaction precedes a reversible electron transfer was established. Also, the rate constants of dissociation of the complexes were determined. Esteban and coworkers also studied the cadmium complexes with nitrilotriacetic acid [74, 75] and fulvic acid [76]. The complexation reaction of cadmium by glycine was investigated by different electrochemical methods using HMDE and mercury microelectrode [77, 78]. 

Thus the rate of electrolysis of O is determined by the magnitude of k in concert with the diffusion process. Metal complexes such as cadmium nitrilotriacetic acid Cd(NTA), in which the metal complex first dissociates to form a hydrated metal ion that then undergoes reduction, fall into this category [6] ... 

Voulgaropoulos et al used a differential pulse anodic-stripping voltammetric method for the indirect trace determination of EDTA and nitrilotriacetic acid in natural waters [22]. To the sample (50 mL, adjusted... 

Voulgaropoulos and Tzivanakis used ion exchangers for the voltammetric determination of nitrilotriacetic acid and EDTA in natural waters [23],... 

Nishikawa and Okumura reported on the determination of EDTA and nitrilotriacetic acid (as their methyl ester derivatives) in environmental samples by GC-MS [48], The sediment for homogenized fish tissues plus EDTA as a surrogate standard in H2O at pH 9-12 was extracted ultrasonically for 10 minutes, centrifuged at 1600 g for 10 minutes, and the supernatant adjusted to pH 2.5 with 4 M formic acid. The sediment was re-centrifuged at 1600 g for 10 minutes, the aqueous phase (the fish extract or water plus CDTA adjusted to pH 2.5) was rotary evaporated to dryness, and the residue methylated with BFs/methanol. The esters were extracted with CH2CI2, the extract concentrated, and a portion was analyzed by GC-MS. The method used a column (25 m x 0.32 mm id) coated with 5% phenylmethylsilicone (0.52 pm), operated with temperature programming from 70°C (held for 4 min) to 300°C (held for 10 min) at 15°C/min with helium (7.5 psi) as the carrier gas. The detection limit was 6.2 ng/mL for EDTA. 

Procedure Separately inject equal volumes (about 50 p-L) of the Standard Preparation and the Test Preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. The retention times are about 3.5 min for nitrilotriacetic acid and 9 min for Disodium EDTA. The response of the nitrilotriacetic acid peak of the Test Preparation does not exceed the difference between the nitrilotriacetic acid peak responses obtained from the Standard Preparation and the Test Preparation. pH of a 1 100 Solution Determine as directed under pH Determination, Appendix IIB. 

Polyaminopolycarboxylic acids, alone or in mixtures, have been determined by measurements of the rate of reaction of cyanide with their Ni(II) complexes. As little as 10 ppb of nitrilotriacetic acid (NTA) in water was detected, and binary, ternary, and even four-component mixtures were determined. The rate-determining step was shown to be... 

Schaffner, C. and W. Giger. 1984. Determination of nitrilotriacetic acid in water by high resolution gas chromatography. /. Chromatogr. 312 413M21. 

Haberman, J.P., 1971. Polarographic determination of traces of nitrilotriacetic acid in water samples. Anal. Chem., 43 63—67. 

Several other complexing reagents are effective masking agents when added to the sample but not to the mobile phase. Nitrilotriacetic acid (NTA) masks a 10- to 100-fold excess of aluminum] 111), copper]II), nickel]II) or iron]III) when magne-sium]II), calcium and manganese] ) are to be determined by IC. Analysis of rare-... 

Indirect polarographic methods are used to determine nitrilotriacetic acid (NTA) and other polyamino acids, e.g., EDTA (auxiliary agents for detergents and cleansers). The methods are based on the formation of stable heavy metal complexes with polarographic properties that are different from those of the acids. Bismuth and cadmium salts are used, added in small excess to the sample. For determination of the acids, use is made of the current signals that are caused either by the excess... 

Aue WA, Hastings CR, Gerhard KO, Pieree JO 111, Hill HH, Moseman RF (1972) The determination of part-per-billion levels of eitrie aeid nitrilotriacetic acids in tap water and sewage effluents. J Chromatogr 72 259-267... 

Manning, Ball, and Menis (162) have carried out polarographic and coulometric reductions of molybdenum (VI) in a nitrilotriacetic acid medium and have applied their findings to the analysis of thorium-uranium oxide mixtures. The determination of molybdenum in steel using coulometric techniques has been reported by Ibrahim and Nair (163) who reduced molybdenum at —0.40 V vs. SCE in a sodium acetate buffered chloride medium. Chromium interference can be removed by pre-reduction with alcohol. The catalytic effect of lower oxidation states of molybdenum in the reduction of perchlorate has been used as an indirect electro-analytical method for the determination of perchlorate (159, 164). 

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