Microdetermination of secondary aliphatic amines using a copper ion-selective electrode

A simple, accurate, and selective method is described for the microdetermination of aliphatic secondary amines. The method is based on their reaction with carbon disulfide and ammoniacal copper sulfate at 40 °C for 30 min to yield copper dialkyldithiocarbamate. The excess copper is then measured by titration with EDTA or NaDDC using a copper ion-selective electrode. A mean recovery of 98.2% with a standard deviation of 0.8% is obtained for aliphatic secondary amines and their salts having a wide range of pK_a.     

Multicomponent condensation of aliphatic amines with formaldehyde and hydrogen sulfide

Cyclothiomethylation of primary aliphatic amines with the reagent H₂S-CH₂O (2:3) in aqueous medium mainly gave substituted dithiazines; oxathiazines and dioxazines were obtained from butylamine and ethanolamine. Under the chosen reaction conditions, ethylenediamine was converted into 5-[2-(perhydro-1,3,5-dithiazin-5-yl)ethyl]perhydro-1,3,5-dithiazine or substituted thiazetidine and oxazetidine, depending on the order of mixing of the starting reagents.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 423–427, February, 2005.     

Use of iodide and silver/sulfide ion-selective electrodes for the determination of some tertiary amines and alkaloids

Summary Some tertiary amines and alkaloides were determined by reaction with methyl iodide at 43 °C. The produced quaternary ammonium iodide salts were potentiometrically titrated with standard silver nitrate solution using either the iodide or silver/sulfide ion-selective electrode. The effects of solvent, temperature and time of reaction were examined. An average recovery of 99.0% and 98.9% with standard deviations of 0.73 and 0.52 were obtained for the studied amines and alkaloides, respectively.

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Verwendung der Iodid-bzw. Silber/Sulfid-selektiven Elektrode zur Bestimmung einiger tertiärer Amine und Alkaloide

     

Laboratory investigation of annular denuders as sampling system for the determination of aliphatic primary and secondary amines in stack gas

A method for the sampling and analysis of aliphatic amines ranging from C₁ to C₅ and some diamines in exhaust gas is described. Two different annular denuder systems coated with phosphoric acid were used for the laboratory investigation of sampling gaseous amines. The denuder sampling systems were tested under different conditions for their readiness to work in stack gas.The reagent 2,4-dinitrofluorobenzene (DNFB) was used in pre-column derivatization of the amines investigated. The amino derivatives were separated using high performance liquid chromatography (HPLC) in conjunction with UV-detection. This method has been used for the examination of emissions from a landfill waste disposal and from animal husbandry with respect to traces of aliphatic amine emissions.     

Comparisons of disposable and conventional silver working electrode for the determination of iodide using high-performance anion-exchange chromatography with pulsed amperometric detection

The paper compared the performance of two kinds of silver working electrode in electrochemical detector-the disposable and conventional electrode for the determination of iodide using high-performance anion-exchange chromatography (HPAEC) hyphenated with pulsed amperometric detection (PAD). The comparisons were carried out on the time of equilibration, long and short-term reproducibility, limits of detection and linearity of calibration. Results showed that disposable working electrode manifested equal or better results than conventional working electrode and could be used for iodide analysis. Besides, the disposable electrode could work for consecutive 2660 min (about 44 h, 10 min needed for each run) with no degradation. Due to its "disposable" property, disposable working electrode could be discarded if the detection sensitivity decreased to 80% so the time for polishing and reconditioning was spared and good reproducible results could be obtained. At last, the disposable electrode was applied for the determination of iodide in soil and sea water samples with the spiked recovery ranging from 96-104% and the detection limit of 0.5 microg/L (10 microL injection, three times of the baseline noise).     

Spectrophotometric determination of aliphatic primary and secondary amines by reaction with p-benzoquinone

A simple, sensitive and selective spectrophotometric method has been developed for determination of aliphatic primary and secondary amines. It is based on a reaction with excess of p-benzoquinone in ethanol whereby 1:1 (amine:quinone) coloured products are obtained, which have maximum absorption at 510 nm and E(1cm)(1%) in the range 400-650. The effect of solvent, temperature, concentration of quinone and the presence of water have been kinetically investigated by the initial rate method. The conditions for monitoring amine concentrations as low as 0.1 microg/ml are optimized in the light of the kinetic data. Results with an average recovery of 98.5% and mean standard deviation of 1.9% are obtained with 9 different amines without interference from tertiary amines, ammonia, amides, imides, anilides, hydrazines and alpha-amino-acids.     

Fabrication of an ion-selective electrode for determination of propylhexedrine

Electrodes of both conventional and micro-sizes were based on the use of propylhexedrine-reineckate as the ion-exchanger in a plastic membrane. The electrodes exhibited Nernstian response towards propylhexedrine (PX) over the concentration range 10^–6–10^–2 M and had life spans of up to 2 days continuous work. The working pH range was 2.3–8. Investigation of diverseions reveals good selectivity for propylhexedrine over several inorganic cations, amines, aminoacids, sugars and some pharmaceutical compounds. The electrode was applied for determination of the drug in urine with 99.1% recovery and 0.15–0.31% relative standard deviation.     

Ultraviolet spectrophotometric determination of primary and secondary aliphatic amines by formation of dithiocarbamates

Primary and secondary aliphatic amines (ca. 0.2–6 μg ml^?1) determined at 250 and 280 nm, respectively, after in situ derivatization to dithiocarbamates in a carbon disulphide/ aqueous sodium hydroxide two-phase system. Alcohols, aromatic and tertiary amines do not interfere.     

Star-shaped tripodal chemosensors for the detection of aliphatic amines

In this work, three new tripodal triphenylamine dyes are presented that are capable of reversibly binding amines and diamines to form hemiaminals through a covalent bond. The dyes were synthesized by the Heck reaction and possess stilbene units with one, two, or three trifluoroacetyl groups as receptor moieties. Their interaction with amines and diamines led to changes in their absorption and emission properties, which were detected by UV/Vis and fluorescence spectroscopy. The influence of the number of trifluoroacetyl receptor moieties on the selectivity and sensitivity of the dyes was studied. Enhanced sensitivity and selectivity for diaminoalkanes was found for the dye we have labeled Tripod-1, with three chemically reactive trifluoroacetyl groups, related to only one or two trifluoroacetyl groups in the dye molecule.     

Rapid, selective and direct spectrophotometeric determination of aliphatic amines with m-dinitrobenzene

Color reaction has been studied for identification and spectrophotometric determination of aliphatic amines at room temperature by m-dinitrobenzene (m-DNB) as reagent. The λ_max value ranges from 458 to 570 nm. This is a simple and rapid method for determination of aliphatic amines in the acidic, water and acetone medium. Beer's law is verified for methylamine, dimethylamine, trimethylamine and n-butylamine in the range of 0.5–8 mg l⁻¹. The effect of pH on the molar absorptivity is investigated for a representative primary amine i.e. methylamine and it was observed that molar absorptivity increases from acidic to basic pH, with a sharp increase at pH 12. The kinetic of reaction was also studied and found that reaction time has marked effect on the molar absorptivity of electron donor–acceptor (EDA) complex. The detection of methyl amine has been reported in three real samples of water.     

Aldehyde cruciforms: dosimeters for primary and secondary amines

We demonstrate that aldehyde-substituted donor-acceptor cruciforms [1,4-bis(arylethynyl)-2,5-distyrylbenzenes] are useful dosimeters for primary amines, primary diamines, and secondary amines. The 1,n-diamines are particularly reactive towards this dosimeter and can be detected in less than 100 ppm concentration. Using a single aldehyde-functionalized cruciform in seven different solvents allowed us to discern fourteen different amines by digital photography and statistical evaluation of the response patterns extracted as red, green, blue (RGB) values.     

中性载体可咯化合物应用于银离子电位传感器的研究

研制了一种以5,10,15-三(五氟苯基)可咯[H_3(tpfc)]为活性组分物质、以邻硝基苯辛醚o-NPOE为增塑剂、以四苯硼钠为亲脂性大阴离子添加剂的PVC膜电极(4种物质的质量比为3:3:62:32),电极能斯特斜率为54.8 mV/decade、工作浓度范围为5.1×10~(-6)～0.1 mol/L,pH为4.0～8.0,响应时间不超过30 s,该电极对银离子能抵抗来自Hg~(2+)、Pb~(2+)等离子干扰,表现出较高的选择性.这种传感器可用于对实际矿石样品进行检测.     

Rapid microwave promoted heterocyclization of primary amines with triethyl orthoformate and sodium azide using zinc sulfide nanoparticles as recyclable catalyst

Microwave assisted synthesis of 1-substituted-1H-tetrazoles was developed using zinc sulfide nanoparticles as heterogeneous catalyst under solvent free conditions. The tetrazole derivatives were easily prepared through hterocyclization of primary amines with triethyl orthoformate and sodium azide in the presence of ZnS NPs. The experimental results were shown that a series of 1-substituted tetrazoles were synthesized under microwave irradiation by ZnS NPs as an effective and reusable heterogeneous catalyst in excellent yields. This protocol has advantages rather than other reported methods such as non-acidic catalyst, solvent free conditions and greener process as well as a solid recyclable catalyst. The catalyst was recovered and reused for several cycles with consistent activity.     

Stopped-flow kinetic determination of aluminum in Chinese tea leaves by fluoride ion-selective electrode potentiometry

A stopped-flow kinetic potentiometric method for the determination of aluminum is described, based on monitoring the reaction between aluminum and fluoride at pH 3.0 using fluoride ion-selective electrode. The initial rate of the reaction is proportional to the concentration of aluminum present in the solution. The method is simple and rapid and has been applied to the determination of aluminum in Chinese tea leaves after microwave digestion.     

N-arylation of primary and secondary aliphatic amines on solid supports

A general and mild method for the N-arylation of primary and secondary aliphatic amines is reported. Copper acetate, triethylamine mediated C/N cross-coupling reaction of arylboronic acids at room temperature to solid-supported primary and secondary amines gave good to excellent yields of the desired N-arylated products.     

A comparison of flow injection methods for sulfide determination based on phenothiazine dyes produced from diverse aromatic amines

In the present work a systematic comparison among spectrophotometric flow injection methods for sulfide determination based on phenothiazine dye production from diverse aromatic p-substituted amines were performed. The behavior of N,N-dimethylphenyl-p-diamine (DMPD), N,N-diethylphenyl-p-diamine (DEPD), phenyl-p-diamine (PPD), p-aminophenol (PAP) and other three aromatic amines was investigated and the chemical parameters of proposed flow methods were optimized by applying central composite design. For each evaluated method the concentration of amine, Fe³⁺ and H₂SO₄ was optimized and after the evaluation of reagents addition order the flow parameters were independently ascertained. Analytical signal was strongly diminished in the presence of iodide for flow methods based on the reaction of sulfide with DMPD, PPD or DEPD while fluoride was considered as an important interference for methods based on the reaction with PPD or PAP. The evaluated aromatic amines have permitted sulfide determination in a wide concentration range from 0.05 to 3.0 mg L^− 1 and limits of detection (3σ) varying from 18.8 to 51.0 μg L^− 1, for DEPD and PPD, respectively. The sensitivity of flow methods based on PPD and DMPD was higher even as PAP has permitted sulfide determination in a large sulfide concentration range. In addition, higher throughput was attained for DMPD method. The proposed methods were applied for sulfide determination in industrial wastewater and the obtained results were in agreement with reference method at 95% confidence level.     

Liquid-phase microextraction and GC for the determination of primary, secondary and tertiary aromatic amines as their iodo-derivatives

Presence of iodine in aromatic amines, introduced by their reaction with iodine, and other electron withdrawing substituents such as chlorine and nitro, has been found to afford excellent liquid-phase microextraction (LPME) in toluene and separation by gas chromatography in the determination of primary, secondary and tertiary aromatic amines. The effect is due to decreased basic nature of amines when electronegative substituents are present. Single drop microextraction (SDME) of the amines in 2 μl of toluene and injection of the whole extract into GC, or LPME into 50 μl of toluene and injection of 2 μl of extract, were used. LPME has been found more robust and to give better extraction in shorter period than SDME. In SDME-GC-FID, the average correlation coefficient was 0.9939 and average limit of detection 25 μg l⁻¹ (range 12-61 μg l⁻¹) whereas the corresponding values in LPME-GC-MS were, respectively, 0.9953 and 33 ng l⁻¹ (range 18-60 ng l⁻¹). The method has been applied to determine aromatic amines in river water, dye factory effluents and food dye stuffs. The LPME was found as robust, rugged and simple extraction method.