Quantitative gas chromatographic determination of nitrilotriacetic acid in the presence of other carboxylic acids.

Nitrilotriacetic acid was separated (as its tri-n-butyl ester) from twenty-four other fatty, phenolic and polycarboxylic acids, using prepacked commercial OV-210 columns. Quantitative analysis down to 0.010 mg nitrilotriacetic acid per liter was demonstrated. The molar responses and retention times of the acids, relative to phthalic acid, were determined.     

A fluorometric method for the determination of nitrilotriacetic acid

The procedure described in this paper can be used to determine trace amounts of nitrilotriacetic acid (NTA) in tap water samples with a relative standard deviation of 10% or less. The procedure does not use expensive equipment, is relatively fast and can be used for routine determination of NTA.     

Analysis of nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) in water, particularly waste water

Summary Two chromatographic techniques can be considered for the detection of the complexing agents NTA, EDTA and DTPA in water: gas chromatography (GC) and liquid chromatography (HPLC). GC is capable of detecting all three compounds in concentrations of as little as 0.001 mg/l. However, this requires a complex and time-consuming sample preparation (enrichment, derivatization). HPLC represents a possible alternative for detecting EDTA and DTPA. Without enrichment it is possible to reach a detection limit of 0.1 mg/l, i.e., while this method is rather less sensitive, it provides results in a much shorter time. If the sample concentrations are high enough, this method is more suitable for conducting routine monitoring of emissions of EDTA and DTPA in waste water. Simple matrices such as surface water or drinking water can be enriched on a pre-column to reduce the detection limit.Dedicated to Professor Dr. Wilhelm Fresenius on the occasion of his 80th birthday     

动力学抑制光度法测定氨三乙酸

氨三乙酸在分析化学中常作为配位滴定剂和掩蔽剂,在催化动力学分析中常作为活化剂。常量的氨三乙酸的测定已有工业化方法,微量氨三乙酸的测定方法极少。酸性和沸水浴条件下,微量的氨三乙酸对高碘酸钾氧化偶氮胭脂红B褪色的反应具有显著的抑制作用,据此建立     

Rapid and sensitive determination of ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid in water samples by ion-pair reversed-phase liquid chromatography--electrospray tandem mass spectrometry

A new method is presented for the quantitative determination of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) from aqueous samples without an enrichment step. It consist of the formation of the Fe(III) complexes of EDTA and DTPA, liquid-chromatography with a volatile ion-pairing agent and determination by electrospray ionization-tandem mass spectrometry (ESI-MS/MS). Limits of quantification (LOQ) of 1.0 and 0.6 microgL(-1) for EDTA and DTPA were obtained, allowing the direct injection of most aqueous environmental samples without any preceding enrichment. With a more recent mass spectrometer, the LOQ could be further decreased by almost one order of magnitude. Parallel analysis of real samples by a standardized method employing enrichment, derivatization and GC-MS analysis yielded comparable results. The method was applied to the determination of both complexing agents in several wastewater, surface water and drinking water samples, showing that EDTA is an omnipresent contaminant in partially closed water cycles.     

Interference of trace amounts of nitrilotriacetic acid in ethylenediaminetetraacetic acid with the spectrophotometric determination of niobium as the niobium—edta—pyrocatechol complex

The effects of 10^-2–10 mol-% NTA in the EDTA used in this determination are reported. Satisfactory results are possible only if the NTA contamination is less than 0.05% ($\text{w}\text{w}$). Even analytical-grade EDTA from some sources may be grossly contaminated.     

Rapid high-performance liquid chromatographic method for the determination of peroxyacetic acid

The selective oxidation of methyl p-tolyl sulfide (MTS) to the corresponding sulfoxide (MTSO) by peroxyacetic acid and the subsequent rapid separation of the sulfide and sulfoxide are the basis for a fast and reliable HPLC method for the determination of this oxidizing agent in the presence of hydrogen peroxide. The time required for chromatographic separation was reduced to less than 1 min. To improve the long-term stability of the sulfoxide solution, hydrogen peroxide was decomposed catalytically by manganese dioxide. Even in the presence of a tenfold molar excess of hydrogen peroxide, a storability of at least 20 h without a significant increase in MTSO concentration was achieved. External calibration can be performed using the stable and commercially available MTSO. Real samples from a brewery cleaning-in-place disinfection process were analysed and the results were compared with those of the classical two-step titration.     

Quantitative high-performance liquid chromatographic determination of sulfur amino acids in protein hydrolysates

A rapid, quantitative high-performance liquid chromatographic procedure for the determination of methionine and cystine after oxidation to methionine sulfone and cysteic acid is described. The Dns derivatives of the amino acids are separated by reversed-phase chromatography with a phosphate buffer-acetonitrile gradient and detected by UV absorption at 254 nm. The procedure is validated by confirming the methionine and cystine content of ribonuclease A. The average yields of cysteic acid and methionine sulfone from triplicate analyses of ribonuclease A were 98.1% (±3.3) and 106.1% (±2.4) of the theoretical values, respectively.     

Fatty acids determination in Bronte pistachios by gas chromatographic method

A gas chromatographic with flame ionization detector (GC-MS FID) method for the identification and quantification of fatty acids based on the extraction of lipids and derivatisation of free acids to form methyl esters was developed and validated. The proposed method was evaluated to a number of standard FAs, and Bronte pistachios samples were used for that purpose and to demonstrate the applicability of the proposed method. In this regard, repeatability, mean and standard deviation of the analytical procedure were calculated. The results obtained have demonstrated oleic acid as the main component of Bronte pistachios (72.2%) followed by linoleic acid (13.4%) and showed some differences in composition with respect to Tunisian, Turkish and Iranian pistachios.     

Spectrophotometric method for determination of sulfide with iron(III) and nitrilotriacetic acid by flow injection

A manual colorimetric method for determination of sulfide has been adapted to flow injection, systematically optimized, and more fully characterized. Its intended application is for measurement of sodium sulfide reagent strength in pulp process streams, and sulfide contamination in effluent from Kraft pulp mills. In the flow-injection method developed, a sample solution containing sulfide is reacted with a mixture of iron(III) and nitrilotriacetic acid under ammoniacal conditions. The absorbance of the intensely-colored green product of this reaction is measured at 636 nm. Excess sulfite is present as a color stabilizer. A linear dynamic range of 20-100 ppm sulfide is readily achieved; the relative standard deviation is less than 1.2% (n = 10) throughout this range, and 0.37% (n = 10) midrange at 60 ppm. The usable dynamic range is 8-250 ppm sulfide. Long-term stability of the method is ensured by periodically performing an automatic cleaning cycle using a hydrochloric acid wash solution. This prevents tube discoloration and removes any precipitates which are formed under strongly alkaline conditions. The sample throuhput rate is at least 30/hr, given alternate acid wash cycles.