Amines In Water Samples Research Articles

Rapid determination of aliphatic amines in water samples by pressure-assisted monolithic octadecylsilica capillary electrochromatography-mass spectrometry.

A pressure-assisted capillary chromatography-mass spectrometry method based on the use of a monolithic octadecylsilica (ODS) capillary is proposed for the determination of aliphatic amines. A 25 mM citric acid buffer containing 10% methanol is used as running electrolyte. Separation is achieved by simultaneously applying a capillary electrophoresis (CE) voltage of 13 kV and an overimposed pressure of 8 bar. The use of pressure is required to ensure stable electrospray conditions. Analysis times are reduced by using a capillary column consisting of a 30 cm long monolithic silica capillary column bound with ODS and a fused-silica capillary column also 30 cm long. The proposed method was successfully applied to the determination of low-molecular-weight aliphatic amines in tap and river water. The analysis of real samples requires cleanup and preconcentration, which can be performed automatically by inserting a minicolumn in the replenishment system of the commercial instrument.

Sensitive determination of aliphatic amines in water by high-performance liquid chromatography with chemiluminescence detection

A sensitive method has been developed for liquid chromatographic determination of short aliphatic amines in water samples. Analytes are preconcentrated and dansylated on solid sorbents (C 18 solid-phase extraction cartridges). The dansyl derivatives are chromatographed and post-column mixed with peroxyoxalate (TCPO) and H 2O 2 in order to perform chemiluminescence detection. Optimal results have been obtained using a sample volume of 5 ml. The method has been applied to the quantification or screening of several aliphatic amines: methylamine, ethylamine, butylamine, diethylamine, pentylamine and hexylamine. The screening procedure has been developed including also polyamines (putrescine, cadaverine, spermidine and spermine). The results obtained by using chemiluminescence (CL) detection have been compared with other detection systems (fluorescence and UV). The sensitivity can increase from 3 to 75 times respect UV detection and from 2 to 10 times respect fluorescence detection depending on the amine. The detection limits achieved were between 0.15 and 0.9 μg/l.

Combination of microporous membrane liquid–liquid extraction and capillary electrophoresis for the analysis of aromatic amines in water samples

A method has been established for the simultaneous analysis of eight aromatic amines in water samples by the combination of capillary zone electrophoresis and microporous membrane liquid–liquid extraction (MMLLE). Eight aromatic amines including N, N-dimethylaniline, m-methylaniline, 3,4-dimethylaniline, 2-naphthylamine, 1-naphthylamine, 4-aminobiphenyl, 2-chloroaniline and 2,4-chloroaniline were well separated under optimal separation conditions. The influence factors relevant to the MMLLE process were investigated and the final optimized parameters were used for analysis. The correlation coefficients were excellent with R 2 values larger than 0.99 and the detection limits (S/N=3) were in the range of 0.16–7.5 ng ml −1. The precision and recoveries were within the ranges of 1.7–13.5 and 78.8–112.6%, respectively.

Aromatic amines from azo dye reduction: status review with emphasis on direct UV spectrophotometric detection in textile industry wastewaters

The present status of origins, known hazards, release restrictions and environmental fate of aromatic amines is reviewed. The specific case of aromatic amines arising from the reduction of the azo bond of azo colorants is addressed, with emphasis on the recalcitrance of azo dyes, their demonstrated vulnerability to azo bond reduction through different mechanisms and the lack of data on the biodegradability of the resulting amines. The evolution and present array of analysis methods for aromatic amines in water samples is reviewed, highlighting the increased sophistication and sensitivity attained, and referring a few efforts towards fast analysis methodologies. The case for the application of direct ultraviolet spectral analysis with advanced deconvolution techniques for the monitoring of aromatic amines in textile effluent treatment is presented.

Analysis of carcinogenic aromatic amines in water samples by solid-phase microextraction coupled with high-performance liquid chromatography

Solid-phase microextraction (SPME) coupled with high-performance liquid chromatography (HPLC) for the analysis of some carcinogenic aromatic amines is described. Carbowax/templated resin (CW/TPR, 50 μm), polydimethylsiloxane/divinylbenzene (PDMS/DVB, 60 μm) and polyacrylate (PA, 85 μm) fibers were evaluated for the extraction efficiency in this work. CW/TPR and PDMS/DVB fibers were selected for further study. Several parameters of the extraction and desorption procedure were studied and optimized (such as types of fibers, extraction time, temperature, pH, ionic strength and organic solute of samples, desorption time, soaking periods and the flow rate during desorption period). PDMS/DVB fiber was recommended for the determination of environmental water samples, since a simple calibration curve method can be used. The detection limits of this method are at the levels of ng/ml.

Analysis of carcinogenic aromatic amines in water samples by solid-phase microextraction coupled with high-performance liquid chromatography

Solid-phase microextraction (SPME) coupled with high-performance liquid chromatography (HPLC) for the analysis of some carcinogenic aromatic amines is described. Carbowax/templated resin (CW/TPR, 50 μm), polydimethylsiloxane/divinylbenzene (PDMS/DVB, 60 μm) and polyacrylate (PA, 85 μm) fibers were evaluated for the extraction efficiency in this work. CW/TPR and PDMS/DVB fibers were selected for further study. Several parameters of the extraction and desorption procedure were studied and optimized (such as types of fibers, extraction time, temperature, pH, ionic strength and organic solute of samples, desorption time, soaking periods and the flow rate during desorption period). PDMS/DVB fiber was recommended for the determination of environmental water samples, since a simple calibration curve method can be used. The detection limits of this method are at the levels of ng/ml.

Preconcentration and dansylation of aliphatic amines using C18 solid-phase packings. Application to the screening analysis in environmental water samples.

Precolumn preconcentration and derivatization on solid sorbents (Bond Elut C18 solid-phase extraction cartridges) of low-molecular-mass aliphatic amines in water samples have been performed using dansyl chloride (Dns-Cl) as derivatization reagent. Conditions for analyte preconcentration and derivatization such as volume sample, reagent concentration, time, pH and temperature reaction were optimised. On the basis of these studies a rapid and sensitive method for screening of aliphatic amines in waters is presented. Up to volumes of 5 ml, samples are drawn through the sorbent, the analytes retained are dansylated at basic pH, at 100 degrees C for 10 min or 85 degrees C for 15 min. The derivatized analytes are desorbed with 0.5 ml of acetonitrile. Twenty microl of the collected extracts are chromatographed in a Hypersyl ODS C18 column using an acetonitrile-imidazole (pH 7) gradient for elution. Seven amines and ammonium were separated within 9 min. The Dns derivatives were monitored at 333 nm with UV detection and at lambda(excitation) = 350 nm and lambda(emission) = 530 nm with fluorescence detection. The different signals are compared. Dynamic ranges from 10 to 250 microg/l and limits of detection at the microgram-per-litre level and relative standard deviations from 2 to 15% were obtained for all the amines. The total analysis time (sample treatment plus chromatography) was less than 25 min. The method was applied to determination and screening analysis of these analytes in real environmental water samples.

Analysis of aromatic amines in water samples by liquid–liquid–liquid microextraction with hollow fibers and high-performance liquid chromatography

Liquid–liquid–liquid microextraction (LLLME) with hollow fibers in high-performance liquid chromatography (HPLC) has been applied as a rapid and sensitive quantitative method for the detection of four aromatic amines (3-nitroaniline, 4-chloroaniline, 4-bromoaniline and 3,4-dichloroaniline) in environmental water samples. The preconcentration procedure was induced by the pH difference inside and outside the hollow fiber. The target compounds were extracted from 4-ml aqueous sample (donor solution, pH∼13) through a microfilm of organic solvent (di- n-hexyl ether), immobilized in the pores of a hollow fiber (1.5 cm length×0.6 mm I.D.), and finally into 4 μl of acid acceptor solution inside the fiber. After a prescribed period of time, the acceptor solution inside the fiber was withdrawn into the microsyringe and directly injected into the HPLC system for analysis. Factors relevant to the extraction procedure were studied. Up to 500-fold enrichment of analytes could be obtained under the optimized conditions (donor solution: 0.1 M sodium hydroxide solution with 20% sodium chloride and 2% acetone; organic phase: di- n-hexyl ether; acceptor solution: 0.5 M hydrochloric acid and 500 m M 18-crown-6 ether; extraction time of 30 min; stirring at 1000 rev./min). The procedure also served as a sample clean-up step. The influence of humic acid on the extraction efficiency was also investigated, and more than 85% relative recoveries of the analytes at two different concentrations (20 and 100 μg/l) were achieved at various concentration of humic acid. This technique is a low cost, simple and fast approach to the analysis of polar compounds in aqueous samples.

Determination of aromatic amines in water samples by capillary electrophoresis with electrochemical and fluorescence detection

Two capillary electrophoresis methods have been compared for the determination of aniline derivatives in environmental water samples. With the first method the anilines were separated as cations by free zone electrophoresis at low pH, and detected by amperometry. For this, the separation capillary was connected through a palladium field decoupler to an electrochemical detection cell which had been modified to match the volume scale of the separation. Most anilines tested, except chlorinated compounds, could be detected with full sensitivity at a detection potential of +0.7 V. Detection limits with this detection scheme were on a low μg/l level. The alternative method involved the derivatization of the anilines with fluorescamine, the separation of the derivatives formed by micellar electrokinetic chromatography, and fluorescence detection. For detection a lamp-based, fibre optics instrument was used. Detection limits with fluorimetry were comparable with those obtained with amperometric detection (in the order of 1 μg/l). Still, this method was preferred since it gave a higher separation efficiency and shorter analysis times (approximately 4 min). The most important argument, however, was its higher reliability and ease-of-handling. Preliminary experiments with water samples collected in areas where pollution with anilines may be expected showed that the method is highly specific, with few interferences showing up in the electropherograms.

Identification of a carcinogenic heterocyclic amine in river water

We investigated the existence of carcinogenic heterocyclic amines in water samples from a river near Kyoto, where several sewage-treatment plants discharge their effluents and water purification plants downstream use this polluted water as their source. Trp-P-2 is one of the carcinogenic heterocyclic amines included in charred meat and is often excreted in human waste in genotoxic fractions. We analysed Trp-P-2 by reverse-phase HPLC using an ODS column and the UV spectrum. Genotoxic potent activities for blue-rayon extracts of river water were detected in the samples at sampling locations. We identified Trp-P-2 in a genotoxic fraction by MS analysis. The concentrations of Trp-P-2 were calculated in the order of 10 −6 mg l −1. These results indicated the existence of carcinogenic heterocyclic amines in the river water. The authors concluded that these carcinogens derive from the effluent of sewage treatment plants including human waste.

Gas chromatographic determination of aromatic amines in water samples after solid-phase extraction and derivatization with iodine: I. Derivatization

A new method for the selective determination of aromatic amines is presented, which is based on the solid-phase extraction at pH 9 and subsequent derivatization of the analytes to the corresponding iodobenzenes. These can selectively and sensitively be determined with gas chromatography and electron-capture detection. Separation of at least 30 compounds in a single chromatographic run in 30 min is possible. With this method, 56 aromatic amines were investigated, and only in six cases no derivatives were obtained. Limits of quantitation were between 0.5 and 8 μg l −1, but may still be lowered with higher sample volumes or different injection techniques. The application to water samples revealed the suitability for the investigation of ground, leachate and wastewater.

Gas chromatographic determination of aromatic amines in water samples after solid-phase extraction and derivatization with iodine: II. Enrichment

A procedure for the enrichment of aromatic amines via solid-phase extraction was developed. A HR-P phase based on styrene–divinylbenzene was used for the investigations, generally followed by derivatization with iodine and determination via GC–ECD. The recoveries of 53 aromatic amines in a drinking water matrix at pH 9 were determined. Most anilines showed relative recoveries between 80–120% with relative standard deviations of ≤5% at concentration levels between 10 and 20 μg l −1. The comparison with a wastewater matrix led to similar results. The enrichment procedure was applied to real samples, e.g., samples of ammunition wastewater.

Determination of aliphatic and alicyclic amines in water by gas and liquid chromatography after derivatization by chloroformates.

Two new methods were developed for the analysis of aliphatic (n-propylamine, pentylamine, hexylamine, heptylamine, octylamine) and alicyclic (pyrrolidine, morpholine, piperidine, piperazine) amines in water samples after derivatization and liquid-liquid-extraction. The carbamate-derivatives formed were determined by GC/MS (trichloroethyl carbamates) as well as by HPLC/fluorescence detection (9-fluorenylmethyl carbamates) in a concentration range between 0.05 and 1.0 microg/l suitable for drinking water analysis. Applications to German rivers and sewage plants show that both new methods produce corresponding results in analysing aliphatic and alicyclic amines in surface waters as well as in waste water samples.

Selective determination of aromatic amines in water samples by capillary zone electrophoresis and solid-phase extraction

The use of a 20:80 (w/w) mixture of keto-derivatized and underivatized poly(styrene-divinylbenzene) copolymer for the selective solid-phase extraction (SPE) of pollutants in environmental water samples is described. In previous paper work, this technique was used for phenol determination with amperometric detection. In this modification, the use of a selective separation technique such as capillary zone electrophoresis (CZE) limits the necessity for obtaining a selective class separation with the extraction procedure. In this case, the same extract as used for phenols was analyzed by CZE in phosphate buffer with UV detection, and the cationic species of interest, aromatic amines, were well separated from all the other non-ionic and anionic compounds. Experimental conditions for the use of CZE and the extraction technique are described. Different recoveries of aromatic amines in environmental samples, linearity and detection limits are discussed.

High-performance liquid chromatography with post-column chemiluminescence detection for simultaneous determination of trace N-nitrosamines and corresponding secondary amines in groundwater

A sensitive, selective and reliable high-performance liquid chromatographic method with chemiluminescence detection is described for the determination of trace N-nitrosamines and corresponding secondary amines simultaneously in environmental water samples. The method combines solid-phase extraction on to a mini activated carbon column, followed by elution with acetone and concentration of the extracts by denitrosation and fluorogenic derivatization. The separation of derivatives was performed on a C18 column (3µm, 83 × 4.6 mm id) with a mobile phase consisting of acetonitrile-water-ethanol (63.5 + 35.5 + 1.0 v/v) containing 3.0 mmol l–1 imidazole and 0.5 mmol l–1 oxalic acid and with a pH of 6.2. Peroxyoxalate chemiluminescence detection was carried out by using bis(2-nitrophenyl) oxalate and hydrogen peroxide as chemilumigenic reagents. The quantitative data obtained (calibration graphs, detection limits, etc.) were analogous to those published previously. Groundwater samples were analysed using the proposed method. Data including the total amounts of secondary amines plus N-nitrosamines, the amount of secondary amines and results of blank experiments from the chromatograms for individual water sample were calculated, then the final concentrations of N-nitrosamines and secondary amines in each water sample were obtained simultaneously. The application of this procedure for determination of N-nitrosamines and corresponding secondary amines in water samples at pmol l–1 and fmol l–1 levels was successfully achieved. The recoveries of various N-nitrosamines and secondary amines added to groundwater samples were excellent (95% for all except two).