共查询到20条相似文献,搜索用时 137 毫秒
1.
The purpose of this study was to establish a simple and sensitive analytical method for lysozyme using Plasmon Resonance Light-Scattering (PRLS) technique with Gold Nanoparticles (AuNPs) as the probe. Nanomolar level of lysozyme induced AuNPs aggregation with enhanced PRLS. For 1.4 nM citrate-capped AuNPs (13 nm in diameter), the linear range of the calibration curve was 15-50 nM with a detection limit of 13.1 nM for lysozyme. Six nanomolar lysozyme can produce an observable PRLS enhancement. Most potential interfering substances present in urine had a negligible effect on the determination. The interference from human serum albumin in the urinary sample can be reduced by precipitating the albumin with ethanol at pH 4.8-4.9. The 90.1-118.2% recovery was achieved for 8 individual lysozyme-spiked urinary samples. This simple and sensitive method for lysozyme does not require sample clean-up and AuNPs modification, thus provided an alternative for urinary lysozyme determination. 相似文献
2.
Ali Mirabi-semnakolaii Parandis Daneshgar Ali Akbar Moosavi-Movahedi Mehdi Rezayat Parviz Norouzi Ali Nemati Mohammad Farhadi 《Journal of Solid State Electrochemistry》2011,15(9):1953-1961
A novel voltammetric method for the determination of trifluralin is proposed based on a composit of carbon paste and copper
nanowire as a sensitive sensor. The presence of copper nanowire in the composite film enhance the conductivity and as a result
increased the electron transfer rate constant and so the current will increase. The composite exhibits a promising higher
electrocatalytic activity towards the oxidation of trifluralin in pH 4.0 aqueous solution. The reduction peak currents of
trifluralin increased remarkably and the reduction peak potential shifted positively at the nanostructuring electrode, compared
with that at a bare CPE which show the enhanced effect of nanowire. The support electrolyte to provide a more defined and
intense peak current for trifluraline determination was 0.05 mol L−1 phosphate buffer at pH 4.0. The fast Fourier transform square wave voltammetry was used as a new electrochemical technique
in flow injection system to abtain more sensitivity by application of discrete fast Fourier transform method by background
subtraction and two-dimensional integration of the electrode response over a selected potential range and time window, the
signal-to-noise ratio has significantly increased and made the sensivity to be higher than other methods. The effective parameters
such as frequency, amplitude, and pH were optimized to get the best sensitivity. As a result, the sensor showed a valuable
response in linear concentration range of 100–0.02 nmol L−1 with a (limit of detection) LOD of 0.008 nmol L−1 and (limit of quantification) LOQ of 0.15 nmol L−1 for trifluralin. A good recovery was obtained for assay spiked urine samples and a good quantification of trifluralin was
achieved in soil samples. 相似文献
3.
We developed a new simple and sensitive assay for lysozyme based on gold nanoparticle plasmon resonance light scattering (PRLS)
measurement and naked-eye detection using for the first time the lysozyme DNA aptamer as the recognition element. Lysozyme
DNA aptamer could stabilize gold nanoparticles (AuNPs) at high ionic strength. Introducing lysozyme to the system easily triggered
the aggregation of AuNPs, producing a red-to-blue color change of the solution, red-shifted plasmon absorption, and enhanced
plasmon resonance light scattering. The linear range was found to be 0.2∼4 nM for 0.7 nM AuNPs, 0.3∼6 nM for 1.4 nM AuNPs
and 0.6∼8 nM for 2.1 nM AuNPs. About 0.1 nM lysozyme can produce an observable enhancement of PRLS signal. For visual detection,
1 nM lysozyme can produce a very distinctive color change. Satisfactory recoveries were obtained for simulated saliva and
diluted urine samples, indicating that the method has potential for analyses of clinical samples. The simplicity and high
sensitivity that are consistent with the resources and needs of many laboratories makes this method a good choice for routine
analysis. 相似文献
4.
D. Leyva J. Estévez A. Montero I. Pupo 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(3):699-705
A sensitive and non chromatographic analytical procedure for the separation of inorganic selenium species in natural water
has been performed. A combination of APDC coprecipitation and determination by an absolute thin layer Energy dispersive X-ray
fluorescence spectrometry method was used. The influence of various analytical parameters such as element concentration, oxidation
states and pH on the recoveries of Se (IV) was examined. The presence of organic matter and bicarbonate anions, typical components
in Cuban groundwater samples, was also tested. Negligible matrix effects were observed. At pH 4 a 100% recovery was found
for Se (IV). The coprecipitation recovery of the oxidized selenium species (Se (VI)) was null for the selected concentration
range (5–100 μg L−1). When the Se (VI) was reduced by heating the solution with 4 mol L−1 HCl, quantitative recovery was also obtained. The determination of total selenium was conducted by the application of the
oxidation–reduction process and the analytical procedure for Se (IV). Se (VI) content was calculated as the difference between
total selenium and Se (IV). The detection limit was 0.13 μg L−1. The relative standard deviation was lower than 3.5% for 5 μg L−1 of Se (IV). The trueness of the method was verified by using standardized hydride generation-atomic absorption spectrometry
technique. The results obtained using the EDXRF technique were in good agreement with the ones determined by HG-AAS. The proposed
method was applied to the determination of Se (IV) in surface water and groundwater samples. 相似文献
5.
Qiong He Tian Gan Dongyun Zheng ShengShui Hu 《Journal of Solid State Electrochemistry》2010,14(6):1057-1064
Simple and sensitive electrochemical method for the determination of nitrite, based on a nano-alumina-modified glassy carbon
electrode (GCE), is described. Nitrite yields a well-defined oxidation peak whose potential is 0.74 V at the nano-alumina-coated
GCE in 0.1 mol L−1 phosphate buffer (pH 5.0). Compared with bare GCE, the nano-alumina-modified GCE has evident catalytic effect towards the
oxidation of nitrite, and its peak current can be significantly enhanced. Some of the experimental parameters were optimized
for the determination of nitrite. The oxidation peak current was proportional to nitrite concentration in the range of 5.0 × 10−8–1.1 × 10−3 mol L−1, and a detection limit of 1.0 × 10−8 mol L−1 was obtained. This method has been successfully used to the determination of nitrite in sausage sample. Furthermore, results
obtained by the method have been compared with spectrophotometric method. 相似文献
6.
A novel rapid and sensitive analytical method, enhanced chemiluminescence with flow-injection sampling, is described for determination
of ciprofloxacin. The method is based on the chemiluminescence reaction of the potassium permanganate–sodium thiosulfate–ciprofloxacin
system. An enhanced chemiluminescence reaction was developed, and optimum conditions for CL emission were investigated. The
chemiluminescence intensity was linearly dependent on ciprofloxacin concentration in the range 1.0×10−8–1.0×10−5 g mL−1. The detection limit was 4×10−9 g mL−1. The relative standard deviation was 1.8% for eleven measurements of 2.0×10−7 g mL−1 ciprofloxacin standard solution. The new method enables simple, sensitive, and rapid determination of ciprofloxacin and has
been successfully used for determination of ciprofloxacin in biological fluids and in ciprofloxacin hydrochloride tablet and
injection. 相似文献
7.
M. Jesús García-Galán Marta Villagrasa M. Silvia Díaz-Cruz Damià Barceló 《Analytical and bioanalytical chemistry》2010,397(3):1325-1334
Robust instrumental analytical chemistry and the subsequent development of improved analytical methodologies and extraction
procedures have enabled the detection at environmental levels of new emerging contaminants, for example pharmaceuticals. The
objective of this study was to explore the potential of liquid chromatography–tandem quadrupole-linear ion trap (LC–QqLIT
MS) for quantitative determination of nine sulfonamides (SAs) and one acetylated metabolite in surface water from the Llobregat
River and one of its main tributaries, the Anoia River, in Catalonia (Spain). A total of 21 samples were taken in three sampling
campaigns. Recoveries ranging from 26% to 123% were calculated for the SAs studied, and method limits of detection (MLODs)
achieved were in the range 0.05–0.2 ng L−1. Through the different campaigns, concentrations ranged from 0.74 ng L−1 (sulfamethizole) to 2,482 ng L−1 (sulfamethazine) in the Llobregat River, and from 0.27 ng L−1 (sulfamethizole) to 168 ng L−1 (sulfamethoxazole) in the Anoia River. Sulfamethoxazole and sulfapyridine were the two SAs most frequently detected (80%
and 71% respectively). N
4-acetylsulfamethazine was detected in both rivers, but with different frequencies (4% of the samples from the Anoia River
and 43% of those from the Llobregat River). Information-dependent acquisition (IDA) experiments were also developed in order
to obtain enhanced product-ion spectra in surface water samples. 相似文献
8.
M N Matos Reyes M L Cervera M de la Guardia 《Analytical and bioanalytical chemistry》2009,394(6):1557-1562
A sensitive and simple analytical method has been developed for determination of Sb(III), Sb(V), Se(IV), Se(VI), Te(IV), Te(VI),
and Bi(III) in garlic samples by using hydride-generation–atomic-fluorescence spectrometry (HG–AFS). The method is based on
a single extraction of the inorganic species by sonication at room temperature with 1 mol L−1 H2SO4 and washing of the solid phase with 0.1% (w/v) EDTA, followed by measurement of the corresponding hydrides generated under two different experimental conditions directly
and after a pre-reduction step. The limit of detection of the method was 0.7 ng g−1 for Sb(III), 1.0 ng g−1 for Sb(V), 1.3 ng g−1 for Se(IV), 1.0 ng g−1 for Se(VI), 1.1 ng g−1 for Te(IV), 0.5 ng g−1 for Te(VI), and 0.9 ng g−1 for Bi(III), in all cases expressed in terms of sample dry weight. 相似文献
9.
Fernando Maya José Manuel Estela Víctor Cerdà 《Analytical and bioanalytical chemistry》2009,394(6):1577-1583
In this work, the hyphenation of the multisyringe flow injection analysis technique with a 100-cm-long pathlength liquid core
waveguide has been accomplished. The Cl−/Hg(SCN)2/Fe3+ reaction system for the spectrophotometric determination of chloride (Cl−) in waters was used as chemical model. As a result, this classic analytical methodology has been improved, minimizing dramatically
the consumption of reagents, in particular, that of the highly biotoxic chemical Hg(SCN)2. The proposed method features a linear dynamic range composed of two steps between (1) 0.2–2 and (2) 2–8 mg Cl− L−1, thus extended applicability due to on-line sample dilution (up to 400 mg Cl− L−1). It also presents improved limits of detection and quantification of 0.06 and 0.20 mg Cl− L−1, respectively. The coefficient of variation and the injection throughput were 1.3% (n = 10, 2 mg Cl− L−1) and 21 h−1. Furthermore, a very low consumption of reagents per Cl− determination of 0.2 μg Hg(II) and 28 μg Fe3+ has been achieved. The method was successfully applied to the determination of Cl− in different types of water samples. Finally, the proposed system is critically compared from a green analytical chemistry
point of view against other flow systems for the same purpose. 相似文献
10.
A compact miniaturized continuous flow system for the determination of urea content in milk 总被引:1,自引:0,他引:1
Willian Toito Suarez Osmundo Dantas Pessoa-Neto Vagner Bezerra dos Santos Ana Rita de Araujo Nogueira Ronaldo Censi Faria Orlando Fatibello-Filho Mar Puyol Julián Alonso 《Analytical and bioanalytical chemistry》2010,398(3):1525-1533
A multicommutation-based flow system with photometric detection was developed, employing an analytical microsystem constructed
with low temperature co-fired ceramics (LTCC) technology, a solid-phase reactor containing particles of Canavalia ensiformis DC (urease source) immobilized with glutaraldehyde, and a mini-photometer coupled directly to the microsystem which monolithically
integrates a continuous flow cell. The determination of urea in milk was based on the hydrolysis of urea in the solid-phase
reactor and the ammonium ions produced were monitored using the Berthelot reaction. The analytical curve was linear in the
urea concentration range from 1.0 × 10−4 to 5.0 × 10−3 mol L−1 with a limit of detection of 8.0 × 10−6 mol L−1. The relative standard deviation (RSD) for a 2.0 × 10−3 mol L−1 urea solution was lower than 0.4% (n = 10) and the sample throughput was 13 h−1. To check the reproducibility of the flow system, calibration curves were obtained with freshly prepared solutions on different
days and the RSD obtained was 4.7% (n = 6). Accuracy was assessed by comparing the results of the proposed method with those from the official procedure and the
data are in close agreement, at a 95% confidence level. 相似文献
11.
We report a sensitive and convenient voltammetric method for the direct determination of 10-hydroxycamptothecin (HCPT). At
a multi-wall carbon nanotube (MWNT)-modified electrode, HCPT yields a very sensitive and well-shaped oxidation peak, which
can be used as analytical signal for HCPT determination. Compared with the poor electrochemical signal at the unmodified GCE,
the electrochemical response of HCPT at the MWNT-modified GCE was greatly improved, as confirmed by the significant peak current
enhancement. This result indicates that the MWNT-modified GCE has great potential in the sensitive determination of HCPT.
Based on this, a very sensitive and simple electrochemical method was proposed for HCPT determination after all the experimental
parameters were optimized. The newly-proposed method possesses very low detection limit (2 × 10−9 mol L−1) and wider linear range (from 1 × 10−8 to 4 × 10−6 mol L−1). Rapid and simple sample analysis is another advantage. Finally, this method was successfully demonstrated using HCPT drugs. 相似文献
12.
Boroujerdi AF Lee PA DiTullio GR Janech MG Vied SB Bearden DW 《Analytical and bioanalytical chemistry》2012,403(3):777-784
In-line solid-phase extraction–capillary electrophoresis coupled with mass spectrometric detection (SPE–CE–MS) has been used
for determination of 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), codeine (COD), hydrocodeine (HCOD), and 6-acetylmorphine
(6AM) in urine. The preconcentration system consists of a small capillary filled with Oasis HLB sorbent and inserted into
the inlet section of the electrophoresis capillary. The SPE–CE–MS experimental conditions were optimized as follows: the sample
(adjusted to pH 6.0) was loaded at 930 mbar for 60 min, elution was performed with methanol at 50 mbar for 35 s, 60 mmol L−1 ammonium acetate at pH 3.8 was used as running buffer, the separation voltage was 30 kV, and the sheath liquid at a flow
rate of 5.0 μL min−1 was isopropanol–water 50:50 (v/v) containing 0.5% acetic acid. Analysis of urine samples spiked with the four drugs and diluted 1:1 (v/v) was studied in the linear range 0.08–10 ng mL−1. Detection limits (LODs) (S/N = 3) were between 0.013 and 0.210 ng mL−1. Repeatability (expressed as relative standard deviation) was below 7.2%. The method developed enables simple and effective
determination of these drugs of abuse in urine samples at the levels encountered in toxicology and doping. 相似文献
13.
On the basis of flow injection analysis technology, a simple, accurate, and sensitive method has been developed for the determination
of volatile phenols in environmental water samples by using CdTe/ZnSe nanocrystals as a fluorescent probe. The influences
of coexisting metal ions and volatile phenol substitutes were also investigated. The method developed for analysis of volatile
phenols displayed very good linearity in the range from 1.0 × 10−8 to 4.0 × 10−7 g L−1, with a correlation coefficient greater than 0.995 and a detection limit down to 2.7 × 10−9 g L−1 (signal-to-noise ratio 3). The proposed method was successfully applied to determine the content of volatile phenols in environmental
water samples, and the quantitative recoveries were 93.4–106.1%. A possible reaction mechanism for the quenching of fluorescence
is discussed using UV–vis absorption spectra, fluorescence spectra, and time-resolved luminescence spectra of volatile phenols
obtained by titrating a CdTe/ZnSe nanocrystal aqueous solution and zeta potential data. 相似文献
14.
M. H. Sorouraddin M. Iranifam A. Imani-Nabiyyi 《Central European Journal of Chemistry》2009,7(1):143-147
A simple and selective method for penicillin V potassium (PVK) determination by chemiluminescence (CL) was developed. Oxidation
of PVK by alkaline hydrogen peroxide produces CL, which is greatly enhanced by N, N-dimethyl formamide (DMF) and N-cetyl-N,N,N-trimethylammonium
bromide (CTMAB). Optimum conditions were established using luminometry. There is a linear relationship between the chemiluminescent
peak height and the amount of PVK within the range 0.5–129.5 mg L−1, with a detection limit of 0.2 mg L−1. The coefficient of variation was 1.2% for 40 mg L−1 PVK solution (n = 7). The method is very simple, has high sensitivity and good selectivity, and is usable for process control.
It was successfully utilized for the determination of PVK in pharmaceuticals and spiked human urine.
相似文献
15.
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
16.
Ainara Barriola José I. Miranda Miren Ostra Carlos Ubide 《Analytical and bioanalytical chemistry》2010,398(2):1085-1094
The use of proton nuclear magnetic resonance (1H-NMR) for the quantification of additives in an electrolytic Zn bath is reported. A simple and quick method is described
that does not need any prior sample preparation. Contrary to other analytical methods, the three additives in the bath, benzylidene
acetone (BDA), benzoic acid (BA) and poly(ethylene glycol) (PE400), can be quantified. Two calibration methods were tried:
integration of NMR signals with the use of an internal standard and partial least squares (PLS) regression applied to the
characteristic NMR peaks. Both methods are compared and the univariate method was preferred because of simplicity, accuracy
and precision. The following limits of detection were found: 0.30 g L−1 BA, 0.08 g L−1 BDA and 0.7 g L−1 PE400 with dynamic ranges of at least 1.0–6.0, 0.1–0.6 and 3.0–18.0 g L−1 respectively. Those concentration ranges are suitable to follow the concentration of additives in the bath in real time.
1H-NMR spectra provide evidence for the BDA degradation pattern. 相似文献
17.
Jamshid L. Manzoori Hossein Abdolmohammad-Zadeh Mohammad Amjadi 《Mikrochimica acta》2007,159(1-2):71-78
A simple and sensitive cloud point extraction method has been developed for the preconcentration of ultra-trace amounts of
gold as a prior step to its determination by electrothermal atomic absorption spectrometry. It is based on the extraction
of gold in hydrochloric acid medium using the non-ionic surfactant polyethyleneglycolmono-p-nonylphenylether (PONPE 7.5) without adding a chelating agent. The preconcentration of a 50 mL sample solution was thus enhanced
by a factor of 200. The resulting calibration graph was linear in the range of 10–200 ng L−1 with a correlation coefficient of 0.9993. The limit of detection (3s) obtained under optimal conditions was 2.0 ng L−1. The relative standard deviation for 10 replicate determinations at a 100 ng L−1 Au level was 3.6%. The method was applied to the ultra-trace determination of gold in water and copper samples. 相似文献
18.
A rapid, sensitive and environmentally friendly method for the analysis of 14 anilines in water samples by dispersive liquid–liquid
microextraction based on solidification of floating organic drop (DLLME-SFO) prior to gas chromatography–mass spectrometry
(GC-MS) was developed and optimized. In the proposed method, cyclohexane was used as the extraction solvent as its toxicity
was much lower than that of the solvent usually used in dispersive liquid–liquid microextraction (DLLME). In the optimized
conditions, the method exhibited good analytical performance. Based on a signal-to-noise ratio of 3, limits of detection for
anilines were in the range of 0.07 to 0.29 μg L−1, and the linear range was 0.5–200 μg L−1 with regression coefficients (r
2) higher than 0.9977. It was efficient for qualitative and quantitative analysis of anilines in water samples. The relative
standard deviations varied from 2.9 to 8.6 % depending on different compounds indicating good precision. Tap water and river
water were selected for evaluating the application to real water samples. The relative recoveries of anilines for the two
real samples spiked with 10 μg L−1 anilines were in the scope of 78.2–114.6 % and 77.3–115.6 %, respectively. 相似文献
19.
Zacarías León Alberto Chisvert Isuha Tarazona Amparo Salvador 《Analytical and bioanalytical chemistry》2010,398(2):831-843
2-Hydroxy-4-methoxybenzophenone (HMB), which is one of the most commonly used UV filters in sunscreen cosmetics to protect
skin from the deleterious effects of the sun, can be percutaneously absorbed, further metabolized, and finally excreted or
bioaccumulated. An analytical method for the sensitive determination of HMB and its three metabolites in both human urine
and semen is developed. The presented analytical method is based on a solid-phase extraction (SPE) procedure to clean-up and
preconcentrate the target analytes from the urine and semen samples followed by liquid chromatography–tandem mass spectrometry
(LC-MS/MS) detection. The methodology was fully validated and the standard addition calibration method was used to quantify
the target analytes in order to correct the matrix effects observed. Considering this approach, the accuracy of the method
was evaluated and the recoveries ranged from 98% to 115% and from 86% to 111% in urine and semen samples, respectively, depending
on the analyte. For urine samples, the limits of detection ranged between 0.027 and 0.103 ng mL−1 and the repeatability of the method, expressed as relative standard deviation, was in the range of 7.2–9.2%, depending on
the analyte. In the case of semen samples, the limits of detection ranged between 1 and 3 ng mL−1 whereas the repeatability was in the range of 2.2–6.4%, depending on the analyte. The described SPE-LC-MS/MS method was satisfactorily
applied to both urine and semen samples from a male volunteer who applied a sunscreen cosmetic product containing HMB. HMB
and its metabolites were found and quantified in the low ng mL−1 range in both urine and semen samples, although at a different extent. 相似文献
20.
The combination of bar adsorptive micro-extraction using activated carbon (AC) and polystyrene–divinylbenzene copolymer (PS-DVB)
sorbent phases, followed by liquid desorption and large-volume injection gas chromatography coupled to mass spectrometry,
under selected ion monitoring mode acquisition, was developed for the first time to monitor pharmaceutical and personal care
products (PPCPs) in environmental water matrices. Assays performed on 25 mL water samples spiked (100 ng L−1) with caffeine, gemfibrozil, triclosan, propranolol, carbamazepine and diazepam, selected as model compounds, yielded recoveries
ranging from 74% to 99% under optimised experimental conditions (equilibrium time, 16 h (1,000 rpm); matrix characteristics:
pH 5, 5% NaCl for AC phase; LD: methanol/acetonitrile (1:1), 45 min). The analytical performance showed good precision (RSD < 18%),
convenient detection limits (5–20 ng L−1) and excellent linear dynamic range (20–800 ng L−1) with remarkable determination coefficients (r
2 > 0.99), where the PS-DVB sorbent phase showed a much better efficiency. By using the standard addition methodology, the
application of the present analytical approach on tap, ground, sea, estuary and wastewater samples allowed very good performance
at the trace level. The proposed method proved to be a suitable sorption-based micro-extraction alternative for the analysis
of priority pollutants with medium-polar to polar characteristics, showing to be easy to implement, reliable, sensitive and
requiring a low sample volume to monitor PPCPs in water matrices. 相似文献