共查询到20条相似文献,搜索用时 31 毫秒
1.
A simple and sensitive method based on capillary electrophoresis (CE) with chemiluminescence (CL) detection has been developed for the determination of uric acid (UA). The sensitive detection was based on the enhancement effect of UA on the CL reaction between luminol and potassium ferricyanide (K3[Fe(CN)6]) in alkaline solution. A laboratory-built reaction flow cell and a photon counter were deployed for the CL detection. Experimental conditions for CL detection were studied in detail to achieve a maximum assay sensitivity. Optimal conditions were found to be 1.0 × 10−4 M luminol added to the CE running buffer and 1.0 × 10−4 M K3[Fe(CN)6] in 0.2 M NaOH solution introduced postcolumn. The proposed CE-CL assay showed good repeatability (relative standard deviation [RSD] = 3.5%, n = 11) and a detection limit of 3.5 × 10−7 M UA (signal/noise ratio [S/N] = 3). A linear calibration curve ranging from 6.0 × 10−7 to 3.0 × 10−5 M UA was obtained. The method was evaluated by quantifying UA in human urine and serum samples with satisfactory assay results. 相似文献
2.
Suqin Han Huili Wang 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(28):2901-2904
A novel capillary electrophoresis (CE) with chemiluminescence (CL) detection method for the determination of mitoxantrone (MTX) has been developed, which based on the CL reaction of potassium ferricyanide with luminol in sodium hydroxide medium sensitized by MTX. Under optimum analytical conditions, MTX is determined over the range of 7.0 × 10−8–1.0 × 10−6 M with a detection limit of 1.0 × 10−8 M. The relative standard deviation (RSD) was 3.7%, 2.6% and 3.0% for 7.0 × 10−8, 5.0 × 10−7 and 1.0 × 10−6 M MTX (n = 11), respectively. In laboratory-built CE–CL apparatus, the proposed method has been applied to determination of MTX in commercial drug and spiked in human urine and plasma with satisfactory results. 相似文献
3.
A microchip electrophoresis (MCE) method with chemiluminescence (CL) detection was developed for the determination of carnosine-related peptides, including carnosine, homocarnosine, and anserine, in biological samples. A simple integrated MCE-CL system was built to perform the assays. The highly sensitive CL detection was achieved by means of the CL reaction between hydrogen peroxide and N-(4-aminobutyl)-N-ethylisoluminol-tagged peptides in the presence of adenine as a CL enhancer and Co2+ as a catalyst. Experimental conditions for analyte labeling, MCE separation, and CL detection were studied. MCE separation of the above-mentioned three peptides took less than 120 s. Detection limits (signal/noise ratio [S/N] = 3) of 3.0 × 10−8, 2.8 × 10−8, and 3.4 × 10−8 M were obtained for carnosine, anserine, and homocarnosine, respectively. The current MCE-CL method was applied for the determination of carnosine, anserine, and homocarnosine in human cerebrospinal fluid (CSF) and canine plasma. Homocarnosine was detected at the micromolar (μM) level in the CSF samples analyzed, whereas the levels of carnosine and anserine in these samples were below the detection limit of the assay. Interestingly, both carnosine and anserine were detected in the canine plasma samples, whereas homocarnosine was not. 相似文献
4.
This article describes the employment of a novel p-phenol derivative, 4-(1,2,4-triazol-1-yl)phenol (TRP), as a highly potent signal enhancer of the luminol-hydrogen peroxide (H2O2)-horseradish peroxidase (HRP) chemiluminescence (CL) system. The CL reaction conditions were optimized, and the enhancement characteristics of TRP were compared with those of p-iodophenol (PIP). TRP produced a strong enhancement of the CL with the effect of prolonging the light emission. The developed system was then applied to the determination of H2O2 with immobilized HRP using magnetic beads as a solid support. The linear range for H2O2 was 2.0 × 10−6 to 1.0 × 10−3 M. The detection limit for H2O2 was 2.0 × 10−6 M. The proposed sensor was applied successfully to the determination of H2O2 in rainwater. 相似文献
5.
The catalytic activity of gold nanoparticles (AuNPs) on a luminol–H2O2 chemiluminescence (CL) system is found to be greatly enhanced after its crosslinking aggregation induced by immunoreaction. Based on this observation, a one-step homogeneous non-stripping CL metalloimmunoassay was designed. In the presence of corresponding antigen (Ag), the immunoreaction caused the aggregation of antibody (Ab)-modified AuNPs, and these crosslinking aggregated AuNPs could catalyze luminol–H2O2 CL reaction to produce a much stronger CL signal than dispersed Ab-modified AuNPs. The assay, including immunoreaction and detection, can be accomplished in homogeneous solution. In the assay, no tedious and strict stripping of metal nanoparticles, difficult synthesis of labels, multiple steps of immunoreactions and washings, and complicated magnetic separation process were required. The detection limit of human immunoglobulin G (IgG, 3σ) was estimated to be as low as 3.2 × 10−11 g ml−1. The sensitivity was increased by two orders of magnitude over that of other AuNP-based CL immunoassay. The current CL metalloimmunoassay offers the advantages of being simple, cheap, rapid, and sensitive. 相似文献
6.
A novel chemiluminescence (CL) method was developed for the determination of 10‐hydroxycamptothecin(HCPT) based on the CL reaction between [Ag(HIO6)2]5? and luminol in alkaline solution. CL emission of Ag(III) complex–luminol in alkaline medium was very different from that in acidic medium. A possible mechanism of enhanced CL emission was suggested. The enhanced effect of HCPT on CL emission of the [Ag(HIO6)2]5?–luminol system was found. The enhanced degree of CL emission was proportional to HCPT concentration. The effect of the reaction conditions on CL emission was examined. Under optimal conditions, the limit of detection was 6.5 × 10?9 g mL?1. The proposed method was applied for the determination of HCPT in real samples with the recoveries of 93.2–109% with the RSD of 1.7–3.3%. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
7.
A square-wave cathodic stripping voltammetry method for alanine determination as its phenylthiohydantoin (PTH-alanine) derivative is developed. To this end, all the chemical and instrumental variables affecting the determination of PTH-alanine are optimized. From studies of the mechanisms governing the electrochemical response of PTH-alanine, it was concluded that it is an electrochemically irreversible system with a diffusive-adsorptive reduction phenomenon. Under optimal conditions, the variation of analytical signal (Ip) with PTH-alanine concentration is linear in the 2.4 × 10−8 − 4.8 × 10−7 M range, with a LOD of 1.2 × 10−8 M and a LOQ of 4.2 × 10−8 M, a RSD (%) less than 11%, and a Er (%) less than 10%. The optimized method was applied to the determination of PTH-alanine obtained from a synthetic protein after Edman reaction and the results were corroborated by high-performance liquid chromatography with UV detection. 相似文献
8.
Large catalase based bioelectrode for biosensor application 总被引:1,自引:0,他引:1
A large catalase (CAT) (Mr ~ 90 kDa), immobilized on multiwalled carbon nanotubes—Nafion® (MWCNT-NF) matrix and encapsulated with polyethylenimine (PEI) on glassy carbon electrode (GCE), showed a pair of nearly reversible cyclic voltammetric peaks for Fe(III)/Fe(II) couple with formal potential of about −0.45 V (vs. Ag/AgCl electrode at pH 7.5). PEI significantly reduced the charge transfer resistance and stabilized the bioelectrode through electrostatic interaction. The electron transfer rate constant and surface coverage of the immobilized CAT were 1.05 ± 0.2 s−1 and 2.1 × 10−10 mol cm−2, respectively. Studies on electrocatalytic activity and kinetics of GCE/MWCNT-NF/CAT/PEI for hydrogen peroxide (H2O2) showed the apparent Michaelis-Menten constant of 3 mM, linear response in the range of 10 μM to 5 mM, response time of ~ 2 s for steady state current, and detection limit of ~ 1 μM. A high operational and storage stability was also demonstrated for the bioelectrode. Hence, the direct electrochemistry of the large catalase and its potential biosensor application have been established through this investigation. 相似文献
9.
A novel flow injection analysis‐direct chemiluminescence (FI‐CL) method has been developed for determination of trace amounts of dopamine (DA) based on the enhancing effect of DA on the CL reaction of luminol with an Ag(III) complex in alkaline solution. Under optimum conditions, CL intensities are proportional to the concentration of DA in the range of 1.0 × 10?10 to 4.0 × 10?8 mol L?1. The detection limit is 3.0 × 10?11 mol L?1 for DA (3s), with a relative standard deviation (n = 13) of 2.3% for 1.0 × 10?8 mol L?1 DA. This method has also been applied for the determination of DA in commercial pharmaceutical injection samples. On the basis of the CL spectra and the results of the free‐radical trapping experiment of this work, a reaction mechanism for this CL reaction is proposed and discussed. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
10.
Jie Wang 《Analytical biochemistry》2010,396(2):304-208
In this work, we fabricated a sensitivity chronocoulometric DNA sensor (CDS) based on gold nanoparticles (AuNPs)/poly(l-lysine) complex film modified glassy carbon electrode. Hexaammineruthenium(III) chloride ([Ru(NH3)6]3+) was used as the electroactive indicator. The assembled process was investigated by cyclic voltammetry (CV) and chronocoulometry (CC). CC is used to monitor the DNA hybridization event by measurement of electrostatic binding [Ru(NH3)6]3+. Under the optimal conditions, the signal of [Ru(NH3)6]3+ was linear with the logarithm of the concentration of the complementary oligonucleotides from 1.0 × 10−13 to 1.0 × 10−11 M, and the detection limit is 3.5 × 10−14 M. 相似文献
11.
Ultrasensitive DNA sensor based on gold nanoparticles/reduced graphene oxide/glassy carbon electrode
Ali Benvidi Afsaneh Dehghani Firouzabadi Seyed Mohammad Moshtaghiun Mohammad Mazloum-Ardakani Marzieh Dehghan Tezerjani 《Analytical biochemistry》2015
We have designed a simple and novel electrochemical biosensor based on glassy carbon electrode (GCE) for DNA detection. GCE was modified with reduced graphene oxide (RGO) and gold nanoparticles (AuNPs) by the electrochemical method, which is helpful for immobilization of thiolated bioreceptors. The electrode modification processes were characterized by scanning electron microscopy (SEM) and electrochemical methods. Then a single-stranded DNA (ssDNA) probe for BRCA1 5382 insC mutation detection was immobilized on the modified electrode for a specific time. The experimental conditions, such as probe immobilization time and target DNA (complementary DNA) hybridization time and temperature with probe DNA, were optimized using electrochemical methods. The electrochemical response for DNA hybridization and synthesis was measured using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) methods. The calibration graph contains two linear ranges; the first part is in the range of 3.0 × 10−20 to 1.0 × 10−12 M, and the second segment part is in the range of 1.0 × 10−12 to 1.0 × 10−7 M. The biosensor showed excellent selectivity for the detection of the complementary sequences from noncomplementary sequences, so it can be used for detection of breast cancer. 相似文献
12.
A polymerized film of 3,5-dihydroxy benzoic acid (DBA) was prepared on the surface of a glassy carbon electrode (GCE) in neutral solution by cyclic voltammetry (CV). The poly(DBA) film-coated GCE exhibited excellent electrocatalytic activity toward the oxidation of dopamine (DA). A linear range of 1.0 × 10−7 to 1.0 × 10−4 M and a detection limit of 6.0 × 10−8 M were observed in pH 7.4 phosphate buffer solutions. Moreover, the interference of ascorbic acid (AA) was effectively eliminated. This work provides a simple and easy approach to selective detection of DA in the presence of AA. 相似文献
13.
Shu-Chen Kan Wei-Feng Chang Min-Chi Lan Chia-Chi Lin Wei-Shiang Lai Chwen-Jen Shieh Kuang-Pin Hsiung Yung-Chuan Liu 《Analytical biochemistry》2015
In this study, a dry assay of l-lactate via the enzymatic chromatographic test (ECT) was developed. An l-lactate dehydrogenase plus a nicotinamide adenine dinucleotide (NADH) regeneration reaction were applied simultaneously. Various tetrazolium salts were screened to reveal visible color intensities capable of determining the lactate concentrations in the sample. The optimal analysis conditions were as follows. The diaphorase (0.5 μl, 2−6 U/μl) was immobilized in the test line of the ECT strip. Nitrotetrazolium blue chloride (5 μl, 12 mM), l-lactate dehydrogenase (1 μl, 0.25 U/μl), and NAD+ (2 μl, 1.5 × 10−5 M) were added into the mobile phase (100 μl) composed of 0.1% (w/w) Tween 20 in 10 mM phosphate buffer (pH 9.0), and the process was left to run for 10 min. This detection had a linear range of 0.039 to 5 mM with a detection limit of 0.047 mM. This quantitative analysis process for l-lactate was easy to operate with good stability and was proper for the point-of-care testing applications. 相似文献
14.
15.
The complex formation of curium(III) with adenosine 5′-triphosphate (ATP) was determined by time-resolved laser-induced fluorescence spectroscopy (TRLFS). The interaction between soluble species of curium(III) with ATP was studied at trace Cm(III) concentrations (3 × 10−7 M). The concentrations of ATP were varied between 6.0 × 10−7 and 1.5 × 10−4 M in the pH range of 1.5-7.0 using 0.154 M NaCl as background electrolyte.Three Cm-ATP species, MpHqLr, could be identified from the fluorescence emission spectra: (i) CmH2ATP+ with a peak maximum at 598.6 nm, (ii) CmHATP with a peak maximum at 600.3 nm, and (iii) CmATP− with a peak maximum at 601.0 nm. The formation constants of these complexes were calculated from TRLFS measurements to be log β121 = 16.86 ± 0.09, log β111 = 13.23 ± 0.10, and log β101 = 8.19 ± 0.16. The hydrated Cm-ATP species showed fluorescence lifetimes between 88 and 96 μs; whereas the CmATP− complex has a significantly longer fluorescence lifetime of 187 ± 7 μs. 相似文献
16.
Basab Bijayi Dhar 《Inorganica chimica acta》2009,362(1):185-188
Titanium(II) solutions, prepared by dissolving titanium metal in triflic acid+HF, react readily with chelated complexes of Ag(III), nickel(IV) and copper(III). Reactions with excess Ti(II) yield Ti(III) and are strongly catalyzed by added Ti(IV), but stoichiometry is unaffected. Rapid reactions of Ti(II) with nonchelated oxidants, VO2+, and do not exhibit catalysis by Ti(IV). Reductions by Ti(III) are unaffected by Ti(IV). The Ag(III)-Ti(II) reaction, as catalyzed by Ti(IV), is subject to kinetic saturation with an association quotient 4 × 102 M−1 for the Ti(IV)-activated species. It is proposed that the catalyzed reductions of the Ag(III) and Ni(IV) oxidants are initiated by 1e− steps, but that the initially formed cation pairs undergo geminate follow-up reactions to give the observed stable products. 相似文献
17.
A novel chemiluminescence (CL) method was developed for the determination of cefazolin sodium based on the CL reaction between the [Cu(HIO6)2]5‐Cu(III) complex and luminol in alkaline solution. Results showed that CL emission of Cu(III) complex–luminol in alkaline medium was significantly different from that in acidic medium. A possible mechanism of the enhanced effect of cefazolin on CL emission of the [Cu(HIO6)2]5‐‐ luminol system was proposed. The effect of the reaction conditions on CL emissions was examined. Under optimized conditions, a good linear relationship was obtained between CL intensity and concentrations of cefazolin sodium in the range of 2.0 x 10‐8 to 2.0 x 10‐6 g/mL with a correlation coefficient of R2 = 0.9978. The limit of detection was 4.58 x 10‐9 g/mL. The proposed method was applied for the determination of cefazolin sodium in real samples with recoveries of 82.0‐109% with an RSD of 0.7‐2.1%. The proposed method was successfully used for the determination of cefazolin sodium in injectable powder preparations and human urine with satisfactory results. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
18.
Saori Itoi Mika TeraoHiroyuki Murota Ichiro Katayama 《Biochemical and biophysical research communications》2013
The endogenous glucocorticoid, cortisol, is released from the adrenal gland in response to various stress stimuli. Extra-adrenal cortisol production has recently been reported to occur in various tissues. Skin is known to synthesize cortisol through a de novo pathway and through an activating enzyme. The enzyme that catalyzes the intracellular conversion of hormonally-inactive cortisone into active cortisol is 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1). We recently reported that 11β-HSD1 is expressed in normal human epidermal keratinocytes (NHEKs) and negatively regulates proliferation of NHEKs. In this study, we investigated the role of 11β-HSD1 in skin inflammation. Expression of 11β-HSD1 was induced by UV-B irradiation and in response to the pro-inflammatory cytokines, IL-1β and TNFα. Increased cortisol concentrations in culture media also increased in response to these stimuli. To investigate the function of increased 11β-HSD1 in response to pro-inflammatory cytokines, we knocked down 11β-HSD1 by transfecting siRNA. Production of IL-6 and IL-8 in response to IL-1β or TNFα stimulation was attenuated in NHEKs transfected with si11β-HSD1 compared with control cells. In addition, IL-1β-induced IL-6 production was enhanced in cultures containing 1 × 10−13 M cortisol, whereas 1 × 10−5 M cortisol attenuated production of IL-6. Thus, cortisol showed immunostimulatory and immunosuppressive activities depending on its concentration. Our results indicate that 11β-HSD1 expression is increased by various stimuli. Thus, regulation of cytosolic cortisol concentrations by 11β-HSD1 appears to modulate expression of inflammatory cytokines in NHEKs. 相似文献
19.
A molecularly imprinted polymers (MIPs) microsensor was presented as a carbon fiber microelectrode (CFME) coating for specifically recognizing xanthine (Xan). The polymeric film was obtained based on the imprinted procedure of electropolymerization of pyrrole in the presence of the template molecule Xan by cyclic voltammetry, and template was removed by magnetic stirring. Under the optimum conditions, a satisfactory molecularly binding selectivity of Xan was obtained from the MIPs microsensor with an imprinting factor (IF) of 6.63 and a linear response to concentration in certain ranges. The ranges are from 4.0 × 10−6 to 6.0 × 10−5 M and from 8.0 × 10−5 to 2.0 × 10−3 M with a detection limit of 2.5 × 10−7 M. Meanwhile, good stability (relative standard deviation [RSD] = 3.2%, n = 10) and reproducibility (RSD = 2.0%, n = 10) were observed, and recoveries ranging from 96.9 to 102.5% were calculated when applied to Xan determination in real blood serum samples. 相似文献
20.
A simple electrochemical sensor for sensitive and selective DNA detection was constructed based on gold nanorods (Au NRs) decorated graphene oxide (GO) sheets. The high-quality Au NRs–GO nanocomposite was synthesized via the electrostatic self-assembly technique, which is considered a potential sensing platform. Differential pulse voltammetry was used to monitor the DNA hybridization event using methylene blue as an electrochemical indicator. Under optimal conditions, the peak currents of methylene blue were linear with the logarithm of the concentrations of complementary DNA from 1.0 × 10−9 to 1.0 × 10−14 M with a detection limit of 3.5 × 10−15 M (signal/noise = 3). Moreover, the prepared electrochemical sensor can effectively distinguish complementary DNA sequences in the presence of a large amount of single-base mismatched DNA (1000:1), indicating that the biosensor has high selectivity. 相似文献