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1.
The fluorescent reagent 6-oxy-(N-succinimidyl acetate)-9-(2′-methoxycarbonyl)fluorescein (SAMF), has been newly synthesized for use as a label for characterization of phosphoamino acids by micellar electrokinetic capillary electrophoresis (MEKC) with laser-induced fluorescence (LIF) detection. The conditions for derivatization and separation of the phosphoamino acids, including pH, concentration of electrolyte, and Brij-35 concentration were optimized in detail. Derivatization was performed at 35 °C for 10min in borate buffer (pH 8.0). The derivatives were separated to baseline by use of running buffer containing 50 mM borate and 20 mM Brij-35 at pH 9.3. Detection limits ranged from 5 × 10?11 to 1 × 10?9 mol L?1 (signal to noise ratio = 3). The method was used for characterization of the phosphoamino acids in a sample from hydrolysis of a novel protein kinase from tobacco cells. 相似文献
2.
The analytical potential of a fluorescein analogue, 6-oxy-(N-succinimidyl acetate)-9-(2'-methoxycarbonyl) fluorescein (SAMF), for the first time synthesized in our laboratory, as a labeling reagent for the labeling and determination of amino compounds by capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection was investigated. Biogenic monoamines and amino acids were chosen as model analytes to evaluate the analytical possibilities of this approach. The derivatization conditions and separation parameters for the biogenic amines were optimized in detail. The derivatization was performed at 30 degrees C for 6 min in boric acid buffer (pH 8.0). The derivatives were baseline-separated in 15 min with 25 mM boric acid running buffer (pH 9.0), containing 24 mM SDS and 12.5% v/v acetonitrile. The concentration detection limit for biogenic amines reaches 8 x 10(-11) mol.L(-1) (signal-to-noise ratio = 3). The application of CE in the analysis of the SAMF-derivatized amino acids was also exploited. The optimal running buffer for amino acids suggested that weak acidic background electrolyte offered better separation than the basic one. The proposed method was applied to the determination of biogenic amines in three different beer samples with satisfying recoveries varying from 92.8% to 104.8%. Finally, comparison of several fluorescein-based probes for amino compounds was discussed. With good labeling reaction, excellent photostability, pH-independent fluorescence (pH 4-9), and the resultant widely suited running buffer pH, SAMF has a great prospect in the determination of amino compounds in CE. 相似文献
3.
In-channel indirect amperometric detection of heavy metal ions for electrophoresis on a poly(dimethylsiloxane) microchip 总被引:2,自引:0,他引:2
In-channel indirect amperometric detection mode for microchip capillary electrophoresis with positive separation electric field is successfully applied to some heavy metal ions. The influences of separation voltage, detection potential, the concentration and pH value of running buffer on the response of the detector have been investigated. An optimized condition of 1200 V separation voltage, −0.1 V detection potential, 20 mM (pH 4.46) running buffer of 2-(N-morpholino)ethanesulfonic acid (MES) + l-histidine (l-His) was selected. The results clearly showed that Pb2+, Cd2+, and Cu2+ were efficiently separated within 80 s in a 3.7 cm long native separation PDMS/PDMS channel and successfully detected at a single carbon fibre electrode. The theoretical plate numbers of Pb2+, Cd2+, and Cu2+ were 1.2 × 105, 2.5 × 105, and 1.9 × 105 m−1, respectively. The detection limits for Pb2+, Cd2+, and Cu2+ were 1.3, 3.3 and 7.4 μM (S/N = 3). 相似文献
4.
Zhang ZX Gao PF Guo XF Wang H Zhang HS 《Analytical and bioanalytical chemistry》2011,401(6):1905-1914
1,3,5,7-Tetramethyl-8-(N-hydroxysuccinimidyl butyric ester)difluoroboradiaza-s-indacene (TMBB-Su), a new BODIPY-based fluorescent probe, was designed and synthesized for the labeling of amino compounds.
It was used as a pre-column derivatizing reagent for determination of amino acid neurotransmitters by high-performance liquid
chromatography (HPLC). The fluorescence quantum yield in acetonitrile increased from 0.84 to 0.95 when it reacted with amino
acid neurotransmitters. Derivatization of TMBB-Su with seven amino acid neurotransmitters was completed within 30 min at 25 °C
in 24.0 mmol L−1 pH 7.8 boric acid buffer. The separation was performed on a C18 column with methanol–water–buffer 55:35:10 (v/v) as mobile phase (buffer: 0.10 mol L−1 H3Cit–0.10 mol L−1 NaOH). Interference from the other concomitant amino acids was eliminated successfully by means of pH gradient elution. With
fluorescence detection at 494 and 504 nm for excitation and emission, respectively, the limits of detection (signal-to-noise
ratio = 3) were from 2.1 to 12.0 nmol L−1. The proposed method has been used to determine amino acid neurotransmitters in the cerebral cortex of mice with cerebral
ischemia at the convalescence stage with satisfactory recoveries varying from 94.9 to 105.2%. 相似文献
5.
M. M. Antonijević R. P. Mihajlović B. V. Vukanović 《Journal of Solid State Electrochemistry》2001,5(1):29-35
The results obtained in potentiometric titrations of copper(II), mercury(II) and iron(III) with standard EDTA solutions are
presented. The titration of copper(II) at pH values in the range from 8.11 to 10.99 (ammonia buffer) and the titration of
mercury(II) and iron(III) at pH values from 3.59 to 5.65 (acetate buffer) were performed. The titration end-point (TEP) was
detected with an indicator electrode made from natural crystalline pyrite as an electrochemical sensor. The results obtained
in potentiometric titration with the pyrite electrode were compared with those obtained using a platinum electrode (Fe3+), a Cu ion selective electrode (Cu2+) and a Hg electrode (Hg2+). Accurate and reproducible results with good agreement were obtained, but higher potential changes at the TEP were obtained
using the pyrite electrode. In the course of the titration the potential was established within less than 1 min, whereas at
the TEP it was within about 2–3 min. The potential changes at the TEP were in the range from 60 to 200 mV per 0.1 ml EDTA,
according to the stability constant of the complex formed. The highest potential changes, ranging from 160 to 200 mV, were
obtained in the titration of iron(III) at pH 3.59. Reverse titration was also performed and accurate and reproducible results
were obtained. Moreover, titration of halogenide and thiocyanate with standard mercury(II) solutions, as well as cyanide with
silver(I) solution, were performed and accurate and reproducible results were again obtained.
Received: 20 February 1998 / Accepted: 19 November 1999 相似文献
6.
A novel catalytic procedure for zirconium was proposed based on Zr(IV) catalyzed oxidation of gallocyanine by hydrogen peroxide
in hexamethylene tetramine-hydrochloric acid buffer medium. The calibration graph is linear for 0–110 ngċml−1, and the detection limit is 0.4 ngċml−1 Zr(IV). Most foreign ions do not interfere with the determination, except for Cu2+, Fe3+ and Cr(VI). The interferences of Cu2+ and Fe3+ could be eliminated by masking with EDTA and mannitol, and that of Cr(VI) by reducing to Cr(III) with ascorbic acid. The
typical features of this procedure are that it is sensitive for zirconium, and the determination could be carried out at room
temperature. It had been used to the determination of zirconium in zirconium bronze, simulated samples and a certified reference
material. The recoveries were 98.6 ∼ 102%, and relative standard deviations (R.S.D.) were 0.9 ∼ 1.5%, respectively.
Received September 12, 1999. Revision April 10, 2000. 相似文献
7.
A new method was developed for the simultaneous determination of lidocaine, proline and lomefloxacin in human urine by capillary
electrophoresis-electrochemiluminescence detection with Ru(bpy)3
2+. Conditions of the separation and detection were investigated and optimized. It was proved that 20 mM phosphate buffer at
pH 6.7 could achieve the most favorable resolution, and the high sensitivity of detection was obtained by using the detection
potential at 1.15 V and 5 mM Ru(bpy)3
2+–60 mM phosphate buffer at pH 7.6 in the detection reservoir. The detection limits were 0.02 μg mL−1 for lidocaine, 0.03 μg mL−1 for proline and 0.06 μg mL−1 for lomefloxacin. Relative standard deviations of the ECL intensity and the migration time were 3.5 and 1.1% for 6 μg mL−1 lidocaine, 3.2 and 1.0% for 6 μg mL−1 proline and 3.7 and 1.2% for 6 μg mL−1 lomefloxacin, respectively. A baseline separation for lidocaine, proline and lomefloxacin was achieved within 360 s. The
developed method was successfully applied to determine the amounts of lidocaine, proline and lomefloxacin in human urine.
The recovery and RSD were in the range of 93.3–97.2 and 3.8–4.9%, respectively. 相似文献
8.
A new spectrofluorimetric method was developed for the determination of trace amounts of coenzyme A (CoA). In the presence
of periodic acid (H5IO6), CoA can remarkably enhance the fluorescence intensity of the Tb3+–ciprofloxacin (CIP) complex at 545 nm in a buffer solution at pH 5.4; the enhanced fluorescence intensity of the Tb3+ ion is proportional to the concentration of CoA. The optimal conditions for the determination of CoA were also investigated.
The linear range and the detection limit for the determination of CoA were 6.08 × 10−6–1.64 × 10−5 and 2.1 × 10−8 mol L−1, respectively. This method is simple, practical and relatively free of interference from coexisting substances, and can be
successfully applied to assess CoA in injection and biological samples. Moreover, the enhancement mechanism of the fluorescence
intensity of the CoA–Tb3+–CIP system in the presence of H5IO6 is also discussed. 相似文献
9.
G. Rezaei Behbehani A. A. Saboury E. Poorakbar L. Barzegar 《Journal of Thermal Analysis and Calorimetry》2010,102(3):1141-1146
A Thermodynamic study on the interaction Jack bean urease, JBU, with Cu2+ ion was studied by isothermal titration calorimetry (ITC) at 300 and 310 K in 30 mM Tris buffer solution, pH 7.0. The heats
of JBU + Cu2+ interactions are reported and analyzed in terms of the extended solvation theory. It was indicated that there are a set of
12 identical and non-cooperative sites for Cu2+ ion. The binding of Cu2+ ion with JBU is exothermic with dissociation equilibrium constants of 284.883 and 345.855 μM at 300 and 310 K, respectively. 相似文献
10.
A.K. Singh Puja Saxena Amit Panwar 《Journal of inclusion phenomena and macrocyclic chemistry》2006,54(3-4):299-305
Copper (II) complex of 2,4-dimethyl-1,5,9,12-tetraazacyclopentadeca-1,4-diene, [Me2(15)dieneN4] was synthesized and used in the fabrication of Cu2+ – selective ISE membrane in PVC matrix. The membrane having Cu(II) macrocyclic complex as electroactive material along with sodium tetraphenyl borate (NaTPB) as anion discriminator. Dibutyl phthalate (DBP) as plasticizer in poly(vinyl chloride) (PVC) matrix was prepared for the determination of Cu2+. The best performance was observed by the membrane having Cu(II) complex–PVC–NaTPB–DBP with composition 1:5:1:3. The sensor worked well over a concentration range 1.12 × 10−6 M–1.0 × 10−1 M between pH 2.1–6.2 and a fast response time 10±2 s and a lifetime of 6 months. Their performance in partially non-aqueous medium was found satisfactory. Electrodes exhibited excellent selectivity for Cu2+ ion over other mono-, di-, trivalent cations. It can also be used as indicator electrode in the potentiometric titration of Cu2+ against EDTA as well as in the determination of Cu2+ in real samples. 相似文献
11.
The spiro form fluorescein hydrazide (1) bearing a cleavable active bond is characterized as a highly selective and sensitive fluorescence probe for Cu2+. In 0.01 M Tris-HCl buffer (pH 7.2), the probe displays a highly selective fluorescence-on response to Cu2+ only, instead of other common metal ions. The reaction mechanism has been explored and proposed as that the hydrazide group of 1 recognizes and binds Cu2+, and the subsequent complexation of Cu2+ promotes hydrolytic cleavage of the amide bond, causing the release of fluorophore (fluorescein) and thereby the retrievement of fluorescence. Conditions for fluorescence measurement were optimized, generating a calibration curve that is linear over the concentration range of 0.1-10 μM Cu2+. The detection limit for Cu2+ is 64 nM based on 11 blank determinations (k = 3), also showing a highly sensitive feature. The fluorescence-on reaction described here has been used for the determination of trace Cu2+ in real biological fluids with satisfactory results. 相似文献
12.
A novel method for the determination of paralytic shellfish poisoning (PSP) toxins using high-performance liquid chromatography
with fluorescence detection was developed. The fluorescent derivates of neosaxitoxin (neoSTX), saxitoxin (STX), gonyautoxins
1 and 4 (GTX1+4), and gonyautoxins 2 and 3 (GTX2+3) were separated on a μBondapak NH2 column (300 mm × 3.9 mm, 10 μm) using water and acetate buffer (pH 6.5) as the mobile phase (1.00 mL min−1) in gradient mode with fluorescence detection at 390 nm (excitation at 330 nm). The linear ranges of neoSTX, STX, GTX1+4
and GTX2+3 were 3.31–331, 0.952–95.2, 3.78–378 and 0.124–12.4 ng mL−1, respectively. The detection limits of neoSTX, STX, GTX1+4 and GTX2+3 were 1.10, 0.32, 1.26 and 0.041 ng mL−1, respectively. The method was successfully applied to the determination of PSP toxins in microalgae. The recoveries ranged
from 88±2% to 107±4% and the relative standard deviations were 0.16% to 4.4%. The procedure is also environmentally friendly
because no organic solvent is used in the mobile phase. 相似文献
13.
Xueyun Li Yifan Guo Tingting Xu Min Fang Qianwen Xu Fan Zhang Zhenyu Wu Cun Li Weiju Zhu 《中国化学会会志》2020,67(6):1070-1077
A novel fluorescent probe CN3, containing 1,8-naphthalimide and picolinate units, was synthesized, and its structure was characterized by 1H nuclear magnetic resonance spectroscopy (H NMR), 13C nuclear magnetic resonance spectroscopy (C NMR), and mass spectroscopy techniques. The detection property of CN3 toward copper ions (Cu2+) has been investigated in ethanol–HEPES buffer (v/v = 1/1, pH = 7.40) solution by UV–Vis absorption and fluorescence emission spectra. The results showed that CN3 had a highly selective and sensitive fluorescence quenching response to Cu2+, which was attributed to the generation of weak fluorescent N-ethyl-4-hydroxyphenyl-1,8- naphthalimide (compound 2) in polar ethanol–HEPES buffer (v/v = 1/1, pH = 7.40) via selective hydrolysis reaction. The detection of CN3 for Cu2+ was not influenced in the presence of other competing metal ions, and the limit of detection was as low as 50.0 nM. Therefore, the color of CN3 changed from colorless to yellowish when the Cu2+ was added. Furthermore, the fluorescent probe CN3 was utilized to detect Cu2+ in real water samples with fine performance. 相似文献
14.
Wei Zhao Aisheng Xiong Xiaoyan Fu Feng Gao Yongsheng Tian Rihe Peng 《Applied biochemistry and biotechnology》2010,162(8):2157-2165
To obtain a high level expression of phytase with favorable characteristics, a codon-optimized phytase gene from Citrobacter freundii was synthesized and transferred into Pichia pastoris. Small-scale expression experiments and activity assays were used to screen positive colonies. After purified by Ni2+–NTA agarose affinity column, the characterizations of the recombinant phytase were determined. The recombinant phytase (r-phyC)
had two distinct pH optima at 2.5 and 4.5 and an optimal temperature at 50 °C. It retained more than 80% activity after being
incubated under various buffer (pH 1.5–8.0) at 37 °C for 1 h. The specific activity, Km, and Vmax values of r-phyC for sodium phytate were 2,072 ± 18 U mg−1, 0.52 ± 0.04 mM, and 2,380 ± 84 U mg−1 min−1, respectively. The enzyme activity was significantly improved by 1 mM of K+, Ca2+, and Mg2+. These characteristics contribute to its potential application in feed industry. 相似文献
15.
Slobodan Brinić Marijo Buzuk Marija Bralić Eni Generalić 《Journal of Solid State Electrochemistry》2012,16(4):1333-1341
The development of Cu(II) solid-contact ion-selective electrodes, based on 1,2-di-(o-salicylaldiminophenylthio)ethane as a neutral carrier, is presented. For the electrodes construction, unmodified carbon ink
(type 1 electrode) and polymer membrane-modified carbon ink (type 2 electrode) were used as solid support and transducer layer.
Also, carbon ink composite polymer membrane electrode (type 3 electrode) was prepared. The analytical performance of the electrodes
was evaluated with potentiometry, while bulk and interfacial electrode features were provided with electrochemical impedance
spectroscopy. It is shown that modification of carbon ink with polymer membrane cocktail decreases the bulk contact resistance
of the transducer layer and polymer membrane, thus enhancing the analytical performance of the electrode in terms of sensitivity,
linear range, and stability of potential. The optimized electrodes of types 2 and 3 exhibit a wide linear range with detection
limits of 1.8 × 10−6 and 1.6 × 10−6 M, respectively. They are suitable for determination of Cu2+ in analytical measurements by direct potentiometry and in potentiometric titrations, within pH between 2.3 and 6.5. The electrodes
are selective for Cu2+ over a large number of tested transition and heavy metal ions. 相似文献
16.
This paper describes the investigation of a molecularly imprinted polymer (MIP) as a sensing receptor for Al3+ ion detection by using an optical approach. Al3+ ion was adopted as the template molecule and 8-hydroxyquinoline sulfonic acid ligand as the fluorescence tag. The polymer
was synthesised using acrylamide as monomer, 2-hydroxyethyl methacrylate as co-monomer and ethylene glycol dimethracylate
as cross-linker. The free radical polymerisation was performed in methanol and initiated by 2,2′-azobisisobutyronitrile at
70 °C. The imprinted polymer was fluorometrically characterised using a fibre optic attachment in a self-designed flow-cell.
NaF was used to leach the Al3+ ion from the MIP. The optimum pH for the rebinding of Al3+ ion with the leached polymer was found to be pH 5 and the fluorescence response was found to be stable within the buffer
strength range of 0.05–0.10 M. The fluorescence intensity during Al3+ ion rebinding was inversely dependent on temperature, and a low interference response (<3%) toward metal ions except for
Cu2+ and Zn2+ ions was observed. The polymer rebinding repeatability study conducted over 9 cycles with Al3+ ion (0.8×10−4 M) was found to give an RSD value of 2.82% with a standard deviation of 0.53. The dynamic range of the system was found to
be linear up to 1.0×10−4 M Al3+ ion with a limit of detection of 3.62 μM. 相似文献
17.
Jilin Yan Jifeng Liu Weidong Cao Xiuhua Sun Xiurong Yang Erkang Wang 《Microchemical Journal》2004,76(1-2):11
A capillary zone electrophoresis with end-column electrochemiluminescence (ECL) detector was described for the determination of benzhexol hydrochloride. The detection was based on the tris(2,2′-bypyridine)ruthenium(II) [Ru(bpy)32+] ECL reaction with the analyte. Electrophoresis was performed using a 25 μm i.d. uncoated capillary. 10 mM sodium phosphate buffer (pH=8.0) was used as the running buffer. The solution in the detection cell was 80 mM sodium phosphate (pH=8.0) and 5 mM Ru(bpy)32+. A linear calibration curve of three-orders of magnitude was obtained (with a correlation coefficient of >0.999) from 1.0×10−8 to 1.0×10−5 M and the limit of detection was 6.7×10−9 M (S/N=3). This just provides an easy and sensitive method to determine the active ingredient in pharmaceutical formulations. 相似文献
18.
An optical chemical sensor based on 2-mercaptopyrimidine (2-MP) in plasticized poly(vinyl chloride) (PVC) membrane incorporating
(N,N-diethyl-5-(octadecanoylimino)-5H benzo[a]phenoxazine-9-amine (ETH 5294) and sodium tetraphenyl borate (NaTPB) for batch and
flow-through determination of mercury ion is described. The response of the sensor is based on selective complexation of Hg2+ with 2-MP in the membrane phase, resulting in an ion exchange process between H+ in the membrane and Hg2+ in the sample solution. The influences of several experimental parameters, such as membrane composition, pH, and type and
concentration of the regenerating reagent, were investigated. The sensor has a response range of 2.0 × 10−9 to 2.0 × 10−5 mol L−1 Hg2+ with a detection limit of 4.0 × 10−10 mol L−1 and a response time of ≤45 s at optimum pH of 6.5 with high measurement repeatability and sensor-to-sensor reproducibility.
It shows high selectivity for Hg2+ over several transition metal ions, including Ag+, Cd2+, Co2+, Cr3+, Cu2+, Fe3+, Mn2+, Ni2+, and common alkali and alkaline earth ions such as Na+, K+, Mg2+, Ca2+, and Pb2+. The sensor membrane can be easily regenerated with dilute acid solutions. The sensor has been used for the determination
of mercury ion concentration in water samples. 相似文献
19.
The simultaneous determination of three isomers of phenylenediamines (o, m, and p-phenylenediamine) and two isomers of dihydroxybenzenes (catechol and resorcinol) in hair dyes was performed by capillary
zone electrophoresis coupled with amperometric detection (CZE–AD). The effects of working electrode potential, pH and concentration
of running buffer, separation voltage, and injection time on CZE–AD were investigated. Under the optimum conditions the five
analytes could be perfectly separated in 0.30 mol L−1 borate–0.40 mol L−1 phosphate buffer (pH 5.8) within 15 min. A 300 μm diameter platinum electrode had good responses at +0.85 V (versus SCE)
for the five analytes. Their linear ranges were from 1.0 × 10−6 to 1.0 × 10−4 mol L−1 and the detection limits were as low as 10−7 mol L−1 (S/N = 3). This working electrode was successfully used to analyze eight kinds of hair dye sample with recoveries in the range
91.0–108.0% and RSDs less than 5.0%. These results demonstrated that capillary zone electrophoresis coupled with electrochemical
detection using a platinum working electrode as detector was convenient, highly sensitive, highly repeatable and could be
used in the rapid determination of practical samples.
Figure Electropherograms obtained from 10 mg mL−1 hair dye sample solutions at a platinum working electrode under optimum CZE–AD conditions: (a) natural black (I), (b) golden: (1) p-phenylenediamine, (2) m-phenylenediamine, (3) o-phenylenediamine, (4) resorcinol, and (5) catechol 相似文献
20.
An Cu(II)-imprinted interpenetrating polymer network (IPN) gel of epoxy-diethylenetriamine and methacrylic acid-acrylamide-N,N′-methylene-bis-(acrylamide) was synthesized by the ionic imprint polymer (IIP) technique. The first polymer network is formed by epoxy gelation
with diethylenetriamine. The other is formed by copper methacrylate co- polymerization with acrylamide and cross-linker N,N′-methylene-bis-(acrylamide). The adsorption–desorption characteristics of the IPN gel as a highly selective solid-phase extraction (SPE)
and preconcentration adsorbent for Cu2+ from aqueous solution were investigated. The experimental results show that trace Cu2+ ions can be quantitatively enriched at pH 5 with recovery >95%. The maximum static adsorption capacity of the ion-imprinted
functionalized gel adsorbent was 76 mg g−1. Comparing with non-imprinted IPN gel, the imprinted IPN gel has higher adsorption capacity and selectivity for Cu2+ by the static adsorption–desorption experiment. Simultaneously, the times of adsorption equilibration and complete desorption
were remarkably short. The precision (RSD) for 11 replicate adsorbent extractions of 20 ng mL−1 Cu2+ was 3.4%. The established procedure was applied to two real water samples with satisfactory results. The prepared ion-imprinted
IPN gel adsorbent was shown to be promising for solid-phase extraction coupled with atomic absorption spectrometry (AAS) for
the determination of trace copper in real samples. In addition, the coordination interaction of Cu2+ and functional groups of the IPN gel adsorbent was primarily discussed by FT-IR spectra. 相似文献