Determination of primary and secondary amines in foodstuffs using gas chromatography and chemiluminescence detection with a modified thermal energy analyser

A simple method is described for the determination of primary and secondary amines in foodstuffs by gas chromatography with a modified thermal energy analyser, operated in the nitrogen mode. Food samples were subjected to mineral oil vacuum distillation and the isolated amines were derivatized with benzenesulphonyl chloride to form the corresponding sulphonamides, which were fractionated to yield primary and secondary amine derivatives using a modified Hinsberg procedure. The detection limit for individual amines using a 10-g food sample was 10 micrograms/kg (ppb) and recoveries were in excess of 80%.     

Trace determination of short-chain aliphatic amines in biological samples by micellar electrokinetic capillary chromatography with laser-induced fluorescence detection

In this study, a new capillary electrophoresis (CE) method is described originally for the sensitive and selective determination of short-chain aliphatic amines in biological samples. These amines were converted into their N-hydroxysuccinimidyl fluorescein-O-acetate (SIFA) derivatives and measured by micellar electrokinetic capillary chromatography with laser-induced fluorescence detection. The derivatization conditions and separation parameters for the aliphatic amines were optimized in detail. The SIFA-labeled amines were fully separated within 8.5 min using 25 mM pH 9.6 boric acid electrolyte containing 60 mM sodium dodecyl sulfate (SDS). The parameters of validation such as linearity of response, precision and detection limits were determined. The detection limits were obtained in the range from 0.02 to 0.1 nM, which was the lowest value reported by CE methods. The developed method was successfully employed to monitor aliphatic amines in serum and cells samples. After comparison of other CE methods using different fluorescent probes, the present method represents a powerful tool for the trace determination of aliphatic amines in complex biological samples.     

Determination of primary and secondary aliphatic amines with high performance liquid chromatography based on the derivatization using 1,3,5,7-tetramethyl-8-(N-hydroxysuccinimidyl butyric ester)-difluoroboradiaza-s-indacene

In this article, the simultaneous determination of primary and secondary aliphatic amines including dimethylamine (DMA), diethylamine and eleven primary aliphatic amines by high performance liquid chromatography (HPLC) with fluorescence detection has been achieved using a BODIPY-based fluorescent derivatization reagent, 1,3,5,7-tetramethyl-8-(N-hydroxysuccinimidyl butyric ester)-difluoroboradiaza-s-indacene (TMBB-Su). The derivatization reaction of TMBB-Su with aliphatic amines was optimized with orthogonal design experiment and the derivatization reaction proceeded at 15 °C for 25 min. The baseline separation of these derivatives was carried out on a C₈ column with methanol-tetrahydrofuran-50 mM pH 6.50 HAc-NaAc buffer (55/5/40, v/v/v) as a mobile phase. Detected at the excitation and emission of 490 and 510 nm, respectively, the detection limits were obtained in the range of 0.01-0.04 nM (signal-to-noise ratio = 3). The proposed method has been applied to the determination of trace aliphatic amines in viscera samples from mice without complex pretreatment or enrichment method. The recoveries ranged from 95.1% to 106.8%, depending on the samples investigated.     

Analysis of aromatic amines as N-propoxycarbonyl derivatives by gas chromatography with nitrogen-phosphorus selective detection

A selective and sensitive method for the analysis of aromatic amines by GC was developed. Aromatic amines were converted to their N-n-propoxycarbonyl derivatives and measured by GC with nitrogen-phosphorus selective detection (NPD) using an HP-5 fused-silica capillary column. The derivatives of the 20 aromatic amines provided excellent NPD responses, and were resolved both quantitatively and reproducibly within 15 min. The calibration curves for aromatic amines in the range 20-500 ng were linear and the detection limits at an S/N of 3 were ca. 19-139 pg injected. This method was applied successfully to combustion smoke and human urine samples, and analyzed without any interference from coexisting substances.     

Sensitive determination of aliphatic amines by high-performance liquid chromatography with a new fluorogenic probe 3-(4-fluorinebenzoyl)-2-quinoline carboxaldehyde

A new fluorogenic reagent 3-(4-fluorinebenzoyl)-2-quinoline carboxaldehyde (FBQCA) has been synthesized and used as a derivatizing reagent for the determination of aliphatic amines with HPLC. The reagent is nonfluorescent, but forms highly fluorescent isoindole upon the reaction with primary amines in alkaline medium. Eleven amine derivatives were baseline separated in 8 min using a gradient elution on a C(8) column and detected with fluorescence detection at lambda(ex)/lambda(em) = 480/546 nm. The detection limits were in the range of 0.5-2 nM (S/N = 3). The proposed method has been successfully applied to the analysis of aliphatic amines in food and environmental samples, including white wine, soybean oil, soil, and tap water with satisfactory recoveries in the range of 94-106%.     

8-Phenyl-(4-oxy-acetic acid N-hydroxysuccinimidyl ester)-4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene as a new highly fluorescent-derivatizing reagent for aliphatic amines in disease-related samples with high-performance liquid chromatography

A novel fluorescent-activated ester, 8-phenyl-(4-oxy-acetic acid N-hydroxysuccinimidyl ester)-4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (TMPAB-OSu) has been designed and synthesized for amine labeling in HPLC. Being used 11 aliphatic amines as the models, the derivatization conditions were optimized. In 0.2 mol/l borate buffer (pH 8.8), amines reacted with TMPAB-OSu at 30 °C to form the derivatives in 10 min. The fluorescent quantum yield of TMPAB-OSu and its amine derivatives are high even compared with fluorescein. The separation of these amine derivatives was achieved with a C₈ column and gradient elution by using 0.1 mol/l sodium acetate buffer (pH 5.0) and methanol. With fluorescence detection at an emission wavelength of 509 nm and an excitation wavelength of 497 nm, the detection limits of aliphatic amines were 2–18 fmol, at a signal-to-noise ratio of 3:1. The proposed TMPAB-OSu-based HPLC method has been applied to the analysis of urine samples of health, hepatic and renal patients and lake water. Recoveries from different matrices are from 96 to 104%, depending on the sample investigated.     

A Rapid HPLC Determination of C2–C7 Aliphatic Diamines by Precolumn Derivatization with Acetylacetone in Methanol-Water

A rapid reversed-phase high performance liquid chromatographic analysis for the determination of seven aliphatic diamines in water is described. Precolumn derivatization with acetylacetone is used for traces of aliphatic diamines in water-methanol (10:1 v/v) medium. The acetylacetone derivatives obtained after 15 min were extracted with an octadecylsilane functionalized silica cartridge, and then injected into the HPLC system. The HPLC system consisted of a reversed-phase column, and a spectrophotometric detector adjusted to 310 nm as elution solvent a methanol-tetrahydrofuran-water (55:3:42 v/v) mixture was used. The acetylacetone derivatives of the C2-C7 diamines were separated with a good resolution in 23 min. The detection limits achieved for each diamine were between 0.18-0.72 ng/ml for a 100 ml water sample. The recovery of diamine derivatives from river and seawater was 88-101%, with relative standard deviations of 2.2-4.0%, and 82-93%, with relative standard deviations of 2.8-4.6%, respectively. Aliphatic diamines are widely used as chemical reagents, occur as metabolic in biomedical studies and are used as chelating agents in analytical chemistry. As they are soluble in water, their use results in their ultimate release to the environment. The need for a sensitive, selective and rapid determination of aliphatic diamines in environmental samples thus has become important. Dobberpuhl et al. [1] have described a highly sensitive pulsed electrochemical detection for aliphatic monoamines and diamines following their chromatographic separation. Although, it is a sensitive method the determination has to be carried out in alkaline conditions. The most common method for the determination of aliphatic amines is high performance liquid chromatography (HPLC), using different derivatives with either fluorescence [2-5] or UV-visible detection [6-11]. The fluorescence detection method most often relies on post-column derivatization, which requires a second pump to deliver the reagent. Acetylacetone is soluble to some degree in water, and has been used as a pre-column derivatization reagent [12]. The reaction only is effective with diamines, and results in UV-active acetylacetone derivatives known as Schiff bases. But acetylacetone requires a long reaction time in water, which makes it rather unsuitable for routine analysis. In this paper an optimized reversed-phase HPLC determination procedure for C2-C7 aliphatic diamines at low ng/ml levels in water is described.     

Determination of hydrazine derivatives by flow-injection analysis with spectrophotometric detection

Flow-injection analysis for the determination of hydrazine derivatives based on their nucleophilic substitution reaction with 4-chloro-5,7-dinitrobenzofurazan in aqueous medium, and spectrophotometric detection has been described. The calibration graphs were linear in the range from 0.15 to 4.0 mug ml(-1) of hydrazine derivatives, with sampling rates of up to 28-32 samples h(-1). Interferences from amino compounds, benzoic acids, aliphatic amines and ammonia have been evaluated. The procedure has been applied to the determination of hydrazine derivatives in serum, urine, appressin drugs and artificial mixtures.     

Simultaneous determination of aliphatic and aromatic amines in water and sediment samples by ion-pair extraction and gas chromatography-mass spectrometry

A gas chromatography-mass spectrometry (GC-MS) method has been proposed for the determination of aliphatic and aromatic amines in a variety of environmental samples including wastewater, river water, sea water and sediment samples. The method includes ion-pair extraction with bis-2-ethylhexylphosphate (BEHPA), derivatisation of compounds with isobutyl chloroformate (IBCF) and their GC-MS analysis. Aliphatic and aromatic amines were isolated from aqueous samples using BEHPA as ion-pair reagent and derivatised with IBCF for their chromatographic analysis. Solid-liquid extraction of aliphatic and aromatic amines in sediment samples were performed in Soxhlet apparatus with acidic MeOH and ion-pair extraction with BEHPA were carried out for the isolation of amines followed by derivatisation with IBCF. Aliphatic and aromatic amines were then analysed with GC-MS in both electron impact (EI) and positive and negative ion chemical ionisation (PNICI) mode as their isobutyloxycarbonyl (isoBOC) derivatives. The obtained recoveries ranged from 81.0 to 98.0% and the precision of this method, as indicated by the relative standard deviations (RSDs) was within the range of 0.5 and 4.3%. The detection limits obtained from calculations by using GC-MS results based on S/N = 3 were within the range from 0.07 to 0.50 ng/l.     

气相色谱-质谱法测定大气颗粒物中的有机胺类物质

建立了大气颗粒物中有机胺类物质的气相色谱-质谱(GC-MS)分析方法.样品用超纯水超声萃取,然后在碱性条件下,用苯磺酰氯(Benzenesulfonyl chloride,BSC)衍生化,衍生物用二氯甲烷萃取,最后用DB-5MS色谱柱分离测定,实现了13种有机胺(包括7种脂肪胺、2种杂环胺和4种芳香胺)的同时测定.本方法的仪器检出限(S/N=3)和定量限(S/N=10)分别为0.00008～0.017 μg/mL和0.00026～0.0565 μg/mL; 标准曲线线性相关系数为0.9903～0.9996,相关性良好;相对标准偏差(RSD)均小于30％, 除低浓度加标水平的甲胺和苯甲胺,其余样品基质加标平均回收率为54.4％～159.7％,大部分胺具有较高的精密度与准确度.将本方法应用于广州城区PM2.5样品的检测, 共检出有机胺9种,其中甲胺、二甲胺和二丁胺约占9种有机胺总和的90％,是PM2.5中主要胺类物质,而丙胺浓度最低,浓度小于1.0 ng/m3.     

脂肪胺的高效液相色谱分离及质谱鉴定

 采用新型荧光试剂1,2-苯并-3,4-二氢咔唑-9-乙酸(BCAA)为柱前衍生化试剂,在Hypersil BDS-C18色谱柱上,通过梯度洗脱对12种游离脂肪胺进行了分离和在线质谱定性。以乙腈为溶剂,1-乙基-3-(3-二甲氨基丙基)环己碳二亚胺(EDAC)为缩合剂,在50 ℃条件下衍生反应15 min后获得稳定的荧光产物。激发波长和发射波长分别为333 nm和390 nm。采用大气压化学电离源(APCI)的正离子模式,实现了土壤和污水中脂肪胺的定性及其含量的测定。脂肪胺的线性相关系数大于0.9993,检测限为12~28 fmol。     

Simultaneous determination of eight short‐chain aliphatic amines in drug substances by HPLC with diode array detection after derivatization with halonitrobenzenes

Short‐chain aliphatic amines are a class of hazardous impurities in drug substances. A simple method, involving derivatization followed by high‐performance liquid chromatography with diode array detection, has been developed for residue determination of eight aliphatic amines simultaneously in drug substances. Different halonitrobenzenes derivatization reagents were systematically compared. As a result, 1‐fluoro‐2‐nitro‐4‐(trifluoromethyl)benzene was selected since the derivatization effectively shifted the absorption wavelength to the visible region (400–450 nm), where most drug substances, impurities and even the derivatization reagent absorb very weakly. Due to the redshift effect, interference was minimized and adequately low limits of quantitation were reached (0.24–0.80 nmol/mL). Moreover, the derivatization reaction was readily carried out in dimethyl sulfoxide at room temperature for 1 h using N ,N‐diisopropylethylamine as catalyst to achieve the highest yield. Without any pre‐treatment, the derivatives were analyzed by high‐performance liquid chromatography with diode array detection. The high stability of the derivatives within 24 h at room temperature (RSD<1.04%) further facilitated the simultaneous preparation and consecutive analysis of quantities of samples. Finally, the proposed method was successfully applied for residue determination of eight aliphatic amines simultaneously in eight drug substance samples. This study could be helpful for the routine analysis and residue control of aliphatic amines in drug substances.     

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.     

6-Oxy-(N-succinimidyl acetate)-9-(2'-methoxycarbonyl)fluorescein as a new fluorescent labeling reagent for aliphatic amines in environmental and food samples using high-performance liquid chromatography

6-Oxy-(N-succinimidyl acetate)-9-(2'-methoxycarbonyl)fluorescein (SAMF), a new fluorescein-based amine-reactive fluorescent probe was well designed, synthesized and used as a pre-column derivatizing reagent for the determination of aliphatic amines in HPLC. It exhibited relatively pH-independent fluorescence (pH 4-9) and excellent photostability. The derivatization was performed at room temperature in 6min. On a C18 column, the derivatives of SAMF with eight aliphatic amines were baseline separated in 28 min with a mobile phase of methanol-water (57:43, v/v) containing 10 mmol l(-1) pH 5.0, H3Cit3-NaOH buffer. With fluorescent detection at lambda(ex)/lambda(em) = 484/516 nm, the detection limit could reach 2-320 fmol (signal-to-noise = 3), which was equivalent to or better than the detection limits obtained from other analytical methods of aliphatic amines. The proposed method has been applied to the determination of the aliphatic amines in environmental and food samples such as lake water, red wine, white wine, and cheese with satisfying recoveries varying from 95 to 106%.     

Determination of amines as pentafluoropropionic acid anhydride derivatives in biological samples using liquid chromatography and tandem mass spectrometry

Determination of amines in biological samples as markers of exposure to the amines or the corresponding isocyanates is an important tool for industrial exposure assessment. In this study, a liquid chromatography and tandem mass spectrometry (LC-MS/MS) method for determination of amines in biological samples as perfluorofatty amides derivatives is presented. The method enables determination of diamines such as methylene diamine (MDA), toluene diamine (TDA), naphthalene diamine (NDA), hexamethylene diamine (HDA), isophorone diamine (IPDA), methylenedi(cyclohexylamine)(HMDA) and 4,4'-methylene-(2-chloroaniline)(MOCA) in human urine and plasma. The work-up procedure included hydrolysis of the biological samples with 3 M H(2)SO(4) at 100 degrees C for 16 h and extraction of the amines into toluene, where derivatisation of the amines with perfluorofatty acid anhydride was performed. Following removal of excess reagent and the acid formed and an exchange of solvent, the derivatives were analysed using gradient elution with an acetonitrile/water mobile phase composition and electrospray ionisation (ESI) with multiple reaction monitoring (MRM) of [M - H](-)-->[M - H - 120](-) or [119](-). Several perfluorofatty acid anhydrides were evaluated as derivatisation reagents, but the LC chromatographic properties of the pentafluoropropionic acid anhydride (PFPA) derivatives were favourable. Quantification of amine-PFPA derivatives was performed using deuterium labelled amine-PFPA derivatives as internals standards with good precision and linearity in the investigated range of 0-20 ng ml(-1) urine. The instrumental detection limits for the amine-PFPA derivatives were 0.2-3 fmol for MRM of [M - H](-)-->[119](-) and 0.3-8 fmol for [M - H](-)-->[M - H - 120](-). In 10 urine and 6 plasma samples from workers exposed to isocyanates, determination of TDA and MDA as PFPA derivatives was performed using LC-MS/MS and a reference GC-MS method. No significant difference between the two methods was observed.     

Gas chromatographic quantification of aliphatic aldehydes in freshly distilled Calvados and Cognac using 3-methylbenzothiazolin-2-one hydrazone as derivative agent

A new precise and sensitive method was used for the quantification of aliphatic aldehydes from C5 to C11 in highly ethanolic beverages such as freshly distilled spirits. Carbonyl compounds were derivatized using 3-methylbenzothiazolin-2-one hydrazone (MBTH) and then separated and detected by gas chromatography-mass spectrometry (GC-MS). Selective mass spectrometric detection of molecular ions of derivatives was performed to obtain a good sensibility (0.2-1.2 microg l(-1)) and a good selectivity. For a concentration of 20 microg l(-1), relative standard deviations were lower than 10% except for heaviest compounds (decanal and undecanal) where RSD were between 11 and 13%. The concentrations of aliphatic aldehydes were determined in nine samples of freshly distilled Calvados and two samples of freshly distilled Cognac with highest concentrations reported for 3-methylbutanal (from 170 to 1220 microg l(-1) in Calvados and from 1540 to 5500 microg l(-1) in Cognac). 3-Methylbutanal and hexanal, due to their low detection thresholds, could be important olfactive markers of these two products. Less than 1h30 is required to quantify the nine studied aliphatic aldehydes in freshly distilled spirits.     

Simultaneous determination of aliphatic and aromatic amines in indoor and outdoor air samples by gas chromatography-mass spectrometry

A gas chromatography-mass spectrometry (GC-MS) method has been proposed for the simultaneous determination of aliphatic and aromatic amines in indoor and outdoor air samples. The method includes pre-concentration of the compounds by percolating the air samples through the acidic solution, ion-pair extraction with bis-2-ethylhexylphosphate (BEHPA), derivatisation of compounds with isobutyl chloroformate (IBCF) and their GC-MS analysis. Aliphatic and aromatic amines were isolated from aqueous samples using BEHPA as ion-pair reagent and derivatised with IBCF for their chromatographic analysis. Aliphatic and aromatic amines were then analysed with GC-MS in both electron impact (EI) and positive and negative ion chemical ionisation (PNICI) mode as their isobutyloxycarbonyl (isoBOC) derivatives. The obtained recoveries ranged from 75.6 to 96.8% and the precision of this method, as indicated by the relative standard deviations (R.S.D.) was within the range of 1.0-4.4%. The detection limits obtained from calculations by using GC-MS results based on S/N: 3 were within the range of 0.08-0.01 ng/m³.     

Determination of low molecular weight aliphatic amines by HPLC in environmental water samples

A high resolution liquid chromatographic method is described for determination of low molecular weight (LMW) aliphatic amines in environmental waters. The analytes after isolation are derivatized by fluram and separated with isocratic elution on octyl (C₈) column, followed by fluorimetric detection in 395/495 nm. Different isolation procedures such as octadecylsilane (ODS) and strong cation exchanger (SCX) solid phase extraction (SPE) cartridges and Amberlite CG-120 resin were evaluated. The quantitative characteristics such as recovery, linear dynamic range, correlation coefficient, limit of detection (LOD), and relative standard deviation (RSD) are presented. Using this method, aliphatic amines were analyzed in rain and tap water as well as in waste water.     

Determination of aliphatic amines by gas chromatography–mass spectrometry after in-syringe derivatization with pentafluorobenzoyl chloride

A simple and highly sensitive gas chromatographic method has been developed for the determination of low molecular weight short-chain aliphatic amines (SCAAs) after their simultaneous extraction and in-syringe derivatization with pentafluorobenzoyl chloride (PFBOC). Derivatization of the low molecular weight aliphatic amines in bicarbonate buffer of pH 10.5 with PFBOC was followed by immersed solvent microextraction. Derivatization conditions, including reagent concentration, reaction pH, ionic concentration of buffer, reaction time, stirring rate, reaction temperature and extraction solvent, have been investigated for method optimization. Linearity was studied within range of 0.15 pg ml⁻¹–50 ng ml⁻¹. The correlation coefficients were between 0.9934 and 0.9999. Detection limit of derivatized amines proved to be in the range of 0.117–1.527 pg ml⁻¹, and the intraday and interday relative standard deviation (RSD) values were less than 8% with respect to peak area. The method was applied for analysis of lake, river and industrial waste water. The recoveries of extraction from lake, river and industrial waste water samples, which have been spiked with different levels of aliphatic amines, were in the range of 68–99%, 63–102% and 62–105%, respectively.     

Optimization of simultaneous derivatization and extraction of aliphatic amines in water samples with dispersive liquid-liquid microextraction followed by HPLC

Dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO) with simultaneous derivatization followed by high-performance liquid chromatography-diode array detection (HPLC-DAD) was applied for preconcentration and determination of primary and secondary aliphatic amines in environmental water samples. A ternary mixture consisting of a disperser, an extractant and a derivatization reagent was used for the simultaneous derivatization and extraction of aliphatic amines in different water samples. The effects of various experimental parameters on derivatization and extraction efficiency were studied simultaneously using experimental design. A Plackett-Burman design was performed for screening of variables in order to determine the significant variables affecting the extraction efficiency. Then, the significant factors were optimized by using a Box-Behnken design (BBD) and the response surface equations were derived. Under optimal conditions, the preconcentration factors were between 210 and 290. The limit of detections (LODs) ranged from 0.005 to 0.02 μg/L and dynamic linear ranges (DLRs) of 0.05-500 and 0.1-500 μg/L were obtained for most of analytes. The performance of the method was evaluated for extraction and determination of primary and secondary aliphatic amines in environmental water samples in micrograms per liter and satisfactory results were obtained (RSDs <12.5%).