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1.
A simple flow injection on line separation and preconcentration system coupled to hydride generation atomic fluorescence spectrometry
(HG-AFS) was developed for ultra-trace cadmium determination in seawater. With the sample pH kept at 3.0, the preconcentration
of cadmium on the inner walls of the knotted reactor was carried out based on the retention of cadmium complex with 1-phenyl-3-methyl-4-benzoylpyrazol-5-one.
A 0.2 mol L−1 HCl was introduced to elute the retained analyte complex and merge with KBH4 solution for HG-AFS detection. Under the optimal experimental conditions, an enhancement factor of 12 was obtained with a
sample consumption of 12.0 mL. The limit of detection was 3.2 ng L−1 with a sample frequency of 24 h−1. The developed method was validated by the analysis of cadmium in certified reference materials, and was applied to the determination
of cadmium in four seawater samples with R.S.D. of around 10%.
Correspondence: Hong Wu, Department of Chemistry, Xuzhou Normal University, Xuzhou 221116, P.R. China 相似文献
2.
Development of a cloud point extraction and preconcentration method for silver prior to flame atomic absorption spectrometry 总被引:1,自引:0,他引:1
The possibility was investigated of using 2-mercaptobenzothiazole (MBT) for Ag(I) concentration by micellar extraction at
cloud point (CP) temperature and subsequent determination by flame atomic absorption spectrometry (FAAS). The method is based
on the complexation of Ag(I) with 2-mercaptobenzothiazole (MBT) in the presence of non-ionic micelles of Triton X-114. The
effect of experimental conditions such as pH, concentration of chelating agent and surfactant, equilibration temperature and
time on cloud point extraction was studied. Under the optimum conditions, the preconcentration of 10 mL of water sample in
the presence of 0.1% Triton X-114 and 2 × 10−4 mol L−1 2-mercaptobenzothiazole permitted the detection of 2.2 ng mL−1 silver. The calibration graph was linear in the range of 10–200 ng mL−1, and the recovery of more than 99% was achieved. The proposed method was used in FAAS determination of Ag(I) in water samples. 相似文献
3.
Silica gel was prepared by the sol–gel method, modified with nanometer-sized zirconium oxide, and this material was characterized
by X-ray diffraction. A micro-column packed with silica gel modified with nanometer zirconium oxide as sorbent has been developed
for the quantitative separation and preconcentration of trace amounts of chromium(III) prior to their determination by electrothermal
atomic absorption spectrometry. Total chromium was determined after the reduction of chromium(VI) to chromium(III) by 10%
(m/v) of aqueous ascorbic acid as reducing reagent. The adsorption capacity for chromium(III) was found to be 2.36 mg g−1. The detection limit for chromium(III) was 15 ng L−1 with an enrichment factor of 100. The relative standard deviation was 3.2% (n = 7, c = 2.0 ng mL−1). 相似文献
4.
N. Negreira I. Rodríguez E. Rubí R. Cela 《Analytical and bioanalytical chemistry》2010,398(2):995-1004
The performance of the dispersive liquid–liquid microextraction (DLLME) technique for the determination of eight UV filters
and a structurally related personal care species, benzyl salicylate (BzS), in environmental water samples is evaluated. After
extraction, analytes were determined by gas chromatography combined with mass spectrometry detection (GC-MS). Parameters potentially
affecting the performance of the sample preparation method (sample pH, ionic strength, type and volume of dispersant and extractant
solvents) were systematically investigated using both multi- and univariant optimization strategies. Under final working conditions,
analytes were extracted from 10 mL water samples by addition of 1 mL of acetone (dispersant) containing 60 μL of chlorobenzene
(extractant), without modifying either the pH or the ionic strength of the sample. Limits of quantification (LOQs) between
2 and 14 ng L−1, inter-day variability (evaluated with relative standard deviations, RSDs) from 9% to 14% and good linearity up to concentrations
of 10,000 ng L−1 were obtained. Moreover, the efficiency of the extraction was scarcely affected by the type of water sample. With the only
exception of 2-ethylhexyl-p-dimethylaminobenzoate (EHPABA), compounds were found in environmental water samples at concentrations between 6 ± 1 ng L−1 and 26 ± 2 ng mL−1. 相似文献
5.
Jibrin Sabo Suleiman Bin Hu Xuli Pu Chaozhang Huang Zucheng Jiang 《Mikrochimica acta》2007,159(3-4):379-385
A new method is proposed using a microcolumn (20 mm × 2.0 mm) packed with nanometer-sized zirconia as solid-phase extractor
for the separation/preconcentration of Mn, Cu, Cr, Zn, Ni and Co prior to their determination by inductively coupled plasma
optical emission spectrometer (ICP-OES) in environmental samples. The factors affecting the separation and preconcentration
of analytes such as pH, sample flow rate and volume, eluent concentration and volume were determined, interfering ions were
studied, and the optimal experimental conditions were established. The adsorption capacity of nanometer-sized ZrO2 for Mn, Cu, Cr, Zn, Ni and Co was found to be 1.3, 1.3, 1.7, 2.0, 3.9 and 1.5 mg g−1, respectively. The detection limits of the method were 12, 58, 24, 2, 7 and 36 ng L−1, respectively, with a preconcentration factor of 25. The precision of this method was 1.7% (Mn), 2.9% (Cu), 5.9% (Mn), 3.8%
(Mn), 6.2% (Mn) and 4.3% (Mn) with 9 determinations of 10 ng mL−1 of target analytes, respectively. The method was successfully applied to the determination of trace metals in lake water,
dried fish samples, certified reference materials of human hair and milk, and provided satisfactory results. 相似文献
6.
Akhmad Sabarudin Osamu Noguchi Mitsuko Oshima Keiro Higuchi Shoji Motomizu 《Mikrochimica acta》2007,159(3-4):341-348
Chitosan resin functionalized with 3,4-dihydroxy benzoic acid (CCTS-DHBA resin) was used as a packing material for flow injection
(FI) on-line mini-column preconcentration in combination with inductively coupled plasma-atomic emission spectrometry (ICP-AES)
for the determination of trace elements such as silver, bismuth, copper, gallium, indium, molybdenum, nickel, uranium, and
vanadium in environmental waters. A 5-mL aliquot of sample (pH 5.5) was introduced to the minicolumn for the adsorption/preconcentration
of the metal ions, and the collected analytes on the mini-column were eluted with 2 M HNO3, and the eluates was subsequently transported via direct injection to the nebulizer of ICP-AES for quantification. The parameters
affecting on the sensitivity, such as sample pH, sample flow rate, eluent concentration, and eluent flow rate, were carefully
examined. Alkali and alkaline earth metal ions commonly existing in river water and seawater did not affect the analysis of
metals. Under the optimum conditions, the method allowed the determination of metal ions with detection limits of 0.08 ng mL−1 (Ag), 0.9 ng mL−1 (Bi), 0.07 ng mL−1 (Cu), 0.9 ng mL−1 (Ga), 0.9 ng mL−1 (In), 0.08 ng mL−1 (Mo), 0.09 ng mL−1 (Ni), 0.9 ng mL−1 (U), and 0.08 ng mL−1 (V). By using 5 mL of sample solution, the enrichment factor and collection efficiency were 8–12 fold and 96–102%, respectively,
whereas the sample throughput was 7 samples/hour. The method was validated by determining metal ions in certified reference
material of river water (SLRS-4) and nearshore seawater (CASS-4), and its applicability was further demonstrated to river
water and seawater samples. 相似文献
7.
Erdal Kendüzler Özcan Yalçınkaya Sıtkı Baytak Ali Rehber Türker 《Mikrochimica acta》2008,160(4):389-395
The preconcentration of chromium(III) by solid phase extraction and its determination from aqueous solutions by flame atomic
absorption spectrometry (FAAS) is investigated by applying an experimental design. The optimization of the preconcentration
variables such as pH of the sample solution, flow rate of the sample solution and concentration of elution solution was carried
out using 23 full factorial design. The most important parameter affecting the preconcentration of chromium is the concentration of eluent.
In the established experimental conditions, chromium can be determined with a relative standard deviation of 2.0% (N = 7) for a chromium concentration of 100 μg L−1. The detection limit for chromium was 1 μg L−1 (N = 20). The adsorption capacity of Amberlyst 36 is found to be 90.9 mg g−1 for chromium. Effect of other ions on the procedure was also evaluated. The method was validated by the analysis of certified
reference materials (tea leaves GBW 07605 and fish tissue IAEA-407). The method was applied to the determination of chromium
in waste water, dam water, carrot, parsley and lettuce.
Correspondence: Ali Rehber Türker, Department of Chemistry, Faculty of Science and Arts, Gazi University, TR-06500 Ankara,
Turkey 相似文献
8.
In weakly acidic buffer medium, vitamin B1 (VB1) interacts with gold nanoparticles to form a binding product, which resulted in a significant enhancement of resonance Rayleigh
scattering (RRS) intensity and the appearance of a new RRS spectrum. The maximum RRS peak was at 368 nm, and there are three
smaller scattering peaks that were at 284 nm, 440 nm and 495 nm, respectively. The enhanced RRS intensity (ΔI) was directly proportional to the concentration of VB1 in the range of 0–2.8 × 10−7 mol L−1. The method had high sensitivity and its detection limit (3σ) was 0.9 ng mL−1. The optimum conditions and the influencing factors have been investigated. The method had good selectivity, which could
be observed from the influence of coexisting substances. A sensitive, simple and fast RRS method for the determination of
VB1 with gold nanoparticle probe has been developed. In addition, the reasons for RRS enhancement were discussed. 相似文献
9.
A novel method for the determination of five sulfonylurea herbicides in soil was developed by a dispersive solid-phase extraction
(DSPE) clean-up followed by dispersive liquid–liquid microextraction (DLLME), prior to sweeping micellar electrokinetic chromatography
(MEKC). In the DSPE-DLLME, 10 g of soil sample was first extracted with 10 mL of acetonitrile containing 5% formic acid (pH 3.0).
The extract was then cleaned-up by a DSPE with C18 as sorbent. A 1 mL aliquot of the resulting extract was then added into a centrifuge tube containing 5 mL of water adjusted
to pH 2.0 and 60.0 μL chlorobenzene (as extraction solvent) for DLLME procedure. Then, the organic sample extraction solution
was evaporated to dryness, and reconstituted with 20.0 μL of 1.0 mmol L−1 Na2HPO4 (pH 10.0) for sweeping-MEKC analysis after DLLME. Under optimized conditions, the method provided as high as 3,000- to 5,000-fold
enrichments factors. The linearity of the method was in the range of 3.3–200 ng g−1 for chlorimuron ethyl and bensulfuron methyl, and in the range of 1.7–200 ng g−1 for tribenuron methyl, chlorsulfuron and metsulfuron methyl, with the correlation coefficients (r) ranging from 0.9965 to 0.9983, respectively. The limits of detection (LODs) ranged from 0.5 to 1.0 ng g−1. The intraday relative standard deviations (RSDs, n = 5) were below 5.3% and interday RSDs (n = 15) within 6.8%. The recoveries of the method for the five sulfonylureas from soil samples at spiking levels of 5.0, 20.0,
and 100.0 ng g−1 were 76.0–93.5%, respectively. The developed method has been successfully applied to the analysis of the target sulfonylurea
herbicide residues in soil samples with a satisfactory result. 相似文献
10.
CdTe quantum dots (QDs) were modified with thioglycolic acid (TGA) and synthesized in aqueous medium. The optimum fluorescence
intensity was found to be at pH 6.24 with a CdTe QDs concentration of 4.96 × 10−7 mol L−1. The quenched fluorescence intensity of CdTe QDs is linearly proportional to V(V) concentration from 10 to 200 ng mL−1 with correlation coefficient R = 0.9985. The limit of detection for V(V) was 2.07 ng mL−1. The proposed method was successfully applied to the analysis of trace amounts of V(V) in water samples with recovery of
96.5–101.8%, and the results were in good agreement with those of electrothermal atomic absorption spectrometry. 相似文献
11.
Bagheri H Aghakhani A Akbari M Ayazi Z 《Analytical and bioanalytical chemistry》2011,400(10):3607-3613
A micro-solid phase extraction technique was developed using a novel polypyrrole-polyamide nanofiber sheet, fabricated by
electrospinning method. The applicability of the new nanofiber sheet was examined as an extracting medium to isolate malathion
as a model pesticide from aqueous samples. Solvent desorption was subsequently performed in a microvial, and an aliquot of
extractant was injected into gas chromatography–mass spectrometry. Various parameters affecting the electrospinning process
including monomer concentration, polyamide content, applied voltage, and electrospinning time were examined. After fabricating
the most suitable preparation conditions, influential parameters on the extraction and desorption processes were optimized.
The developed method proved to be rather convenient and offers sufficient sensitivity and good reproducibility. The limit
of detection (S/N = 3) and limit of quantification (S/N = 10) of the method under optimized conditions were 50 and 100 ng L−1, respectively. The relative standard deviation at concentration level of 1 ng mL−1 was 2% (n = 3). The calibration curve of analyte showed linearity in the range of 0.1–1 ng mL−1 (R
2 = 0.9975). The developed method was successfully applied to tap and Zayanderood river water samples, while the relative recovery
percentages of 98% and 96% were obtained, respectively. The whole procedure showed to be conveniently applicable and quite
easy to be manipulated. 相似文献
12.
Reddithota J. Krupadam Bhagyashree Bhagat Muntazir S. Khan 《Analytical and bioanalytical chemistry》2010,397(7):3097-3106
A method based on solid--phase extraction with a molecularly imprinted polymer (MIP) has been developed to determine five
probable human carcinogenic polycyclic aromatic hydrocarbons (PAHs) in ambient air dust by gas chromatography-mass spectrometry
(GC-MS). Molecularly imprinted poly(vinylpyridine-co-ethylene glycol dimethacrylate) was chosen as solid-phase extraction
(SPE) material for PAHs. The conditions affecting extraction efficiency, for example surface properties, concentration of
PAHs, and equilibration times were evaluated and optimized. Under optimum conditions, pre-concentration factors for MIP-SPE
ranged between 80 and 93 for 10 mL ambient air dust leachate. PAHs recoveries from MIP-SPE after extraction from air dust
were between 85% and 97% and calibration graphs of the PAHs showed a good linearity between 10 and 1000 ng L−1 (r = 0.99). The extraction efficiency of MIP for PAHs was compared with that of commercially available SPE materials—powdered
activated carbon (PAC) and polystyrene-divinylbenzene resin (XAD)—and it was shown that the extraction capacity of the MIP
was better than that of the other two SPE materials. Organic matter in air dust had no effect on MIP extraction, which produced
a clean extract for GC-MS analysis. The detection limit of the method proposed in this article is 0.15 ng L−1 for benzo[a]pyrene, which is a marker molecule of air pollution. The method has been applied to the determination of probable carcinogenic
PAHs in air dust of industrial zones and satisfactory results were obtained. 相似文献
13.
In this paper, 4-hydroxy-1-naphthalthiorhodanine (HNTR) was synthesized, and a new method for the simultaneous determination
of palladium, platinum and rhodium ions as metal-HNTR chelates was developed using rapid column high-performance liquid chromatography
combined with on-line enrichment. The palladium, platinum and rhodium ions were pre-column derivatized with HNTR to form colored
chelates. The Pb-HNTR, Pt-HNTR and Rh-HNTR chelates could be absorbed onto the front of the enrichment column when they were
injected into the injector and sent to the enrichment column [ZORBAX Stable Bound, 4.6 × 10 mm, 1.8 μm] with a buffer solution
of 0.05 mol L−1 sodium acetate-acetic acid (pH 4.0) as mobile phase. After enrichment, and by switching the six-ports switching valve, the
retained chelates were back-flushed by mobile phase and traveling towards the analytical column. Separation of these chelates
on the analytical column [ZORBAX Stable Bound, 4.6 × 50 mm, 1.8 μm] was satisfactory with 68% acetonitrile (containing 0.05 mol L−1 of pH 4.0 sodium acetate-acetic acid buffer salt and 0.1% of tritonX-100) as mobile phase. Palladium, platinum and rhodium
were separated completely within 2 min. The detection limits (S/N = 3) of palladium, platinum and rhodium are 1.2 ng L−1, 1.5 ng L−1 and 1.8 ng L−1, respectively. This method was applied to the determination of palladium, platinum and rhodium in water, urine and soil samples
with good results. 相似文献
14.
Jun Yue Bai Liang Wang Hong Jing Wang Peng Fei Huang Yu Qing Zhao Sheng Di Fan 《Mikrochimica acta》2006,156(3-4):321-326
The electrochemical behavior of epinephrine (EP) at a mercaptoacetic acid (MAA) self-assembled monolayer modified gold electrode
was studied. The MAA/Au electrode is demonstrated to promote the electrochemical response of epinephrine by cyclic voltammetry.
The possible reaction mechanism is also discussed. The diffusion coefficient D of EP is 6.85 × 10−6 cm2 s−1. In 0.1 mol L−1 phosphate buffer (pH 7.20), a sensitive oxidation peak was observed at 0.177 V, and the peak current is proportional to the
concentration of EP in the range of 1.0 × 10−5–2.0 × 10−4 mol L−1 and 1.0 × 10−7–1.0 × 10−6 mol L−1. The detection limit is 5 × 10−8 mol L−1. The modified electrode is highly stable and can be applied to the determination of EP in practical injection samples. The
method is simple, quick, sensitive and accurate. 相似文献
15.
A novel molecularly imprinted polymer solid-phase extraction (MISPE) with flow-injection chemiluminescence (CL) was developed
for the determination of pazufloxacin mesilate (PZFX). The molecularly imprinted polymer (MIP) was synthesized by using PZFX
as the imprinting molecule. A glass tube packed the particles of the MIP was employed as MISPE micro-column, which was connected
into the sampling loop of the eight-way injection valve for on-line selective preconcentration and extraction of PZFX. The
eluent of acetonitrile:acetic acid (9:1, v:v) was used as carrier for eluting the adsorbed PZFX to react with the mixture
of cerium(IV) and sodium sulfite in the flow cell to produce strong CL. The relative intensity of CL was linear to PZFX concentration
in the range from 2.5 × 10−9 to 2.5 × 10−7 g mL−1. The limit of detection was 7 × 10−10 g mL−1 (3 σ) and the relative standard deviation for 5 × 10−8 g mL−1of PZFX solution was 3.7% (n = 7). This method has been applied to the determination of PZFX in human urine. 相似文献
16.
A flow injection system was developed for on-line sorbent extraction preconcentration and flame atomic absorption spectrometric
determination of cadmium in natural water samples. The non-charged cadmium complex with diethyl-dithiophosphate (DDPA) was
formed on-line in 0.1 mol L−1 HNO3 and retained on the hydrophobic poly-chlorotrifluoroethylene (PCTFE) sorbent material. The adsorbed complex was eluted with
isobutyl methylketone (IBMK) and injected directly into the nebulizer via a flow compensation unit. All major chemical and
flow parameters affecting the complex formation adsorption and elution as well as interference were studied and optimized.
By processing 2.4 mL of sample, the enhancement factor was 39 and the sampling frequency was 50 h−1. For 30 s preconcentration time the detection limit was 0.3 μg L−1 and the relative standard deviation at 5.0 μg L−1 Cd concentration level was 2.9%. The calibration curve was linear in the range 0.8–40.0 μg L−1. The accuracy of the method was estimated by analyzing a certified reference material NIST-CRM 1643d (Trace elements in water).
Good recoveries were obtained for spiked natural-water and waste-water samples.
Correspondence: Aristidis N. Anthemidis, Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University,
GR-Thessaloniki 54124, Greece 相似文献
17.
Viñas P López-García I Bravo-Bravo M Briceño M Hernández-Córdoba M 《Analytical and bioanalytical chemistry》2012,403(4):1059-1066
A miniaturized dispersive liquid–liquid microextraction (DLLME) procedure coupled to liquid chromatography (LC) with fluorimetric
detection was evaluated for the preconcentration and determination of thiamine (vitamin B1). Derivatization was carried out by chemical oxidation of thiamine with 5 × 10−5 M ferricyanide at pH 13 to form fluorescent thiochrome. For DLLME, 0.5 mL of acetonitrile (dispersing solvent) containing
90 μL of tetrachloroethane (extraction solvent) was rapidly injected into 10 mL of sample solution containing the derivatized
thiochrome and 24% (w/v) sodium chloride, thereby forming a cloudy solution. Phase separation was carried out by centrifugation, and a volume of
20 μL of the sedimented phase was submitted to LC. The mobile phase was a mixture of a 90% (v/v) 10 mM KH2PO4 (pH 7) solution and 10% (v/v) acetonitrile at 1 mL min−1. An amide-based stationary phase involving a ligand with amide groups and the endcapping of trimethylsilyl was used. Specificity,
linearity, precision, recovery, and sensitivity were satisfactory. Calibration graph was carried out by the standard additions
method and was linear between 1 and 10 ng mL−1. The detection limit was 0.09 ng mL−1. The selectivity of the method was judged from the absence of interfering peaks at the thiamine elution time for blank chromatograms
of unspiked samples. A relative standard deviation of 3.2% was obtained for a standard solution containing thiamine at 5 ng mL−1. The esters thiamine monophosphate and thiamine pyrophosphate can also be determined by submitting the sample to successive
acid and enzymatic treatments. The method was applied to the determination of thiamine in different foods such as beer, brewer’s
yeast, honey, and baby foods including infant formulas, fermented milk, cereals, and purees. For the analysis of solid samples,
a previous extraction step was applied based on an acid hydrolysis with trichloroacetic acid. The reliability of the procedure
was checked by analyzing a certified reference material, pig’s liver (CRM 487). The value obtained was 8.76 ± 0.2 μg g−1 thiamine, which is in excellent agreement with the certified value, 8.6 ± 1.1 μg g−1. 相似文献
18.
Samuel Melaku Ilse Gelaude Frank Vanhaecke Luc Moens Richard Dams 《Mikrochimica acta》2003,142(1-2):7-12
Microwave digestion reduction-aeration and pyrolysis combined with cold vapour atomic absorption and cold vapour atomic fluorescence
are compared for the determination of total mercury in several biological and environmental matrices. The biological samples
were digested in a mixture of HNO3/H2O2, the environmental samples in a mixture of HNO3/HClO4. After reduction with SnCl2, the mercury was collected by two-stage gold amalgamation. After microwave digestion reduction-aeration, detection limits
of 1.4 ng g−1 and 0.6 ng g−1 were obtained for cold vapour atomic absorption spectrometry (CVAAS) and cold vapour atomic fluorescence spectrometry (CVAFS),
respectively, for 250 mg of environmental samples. For biological samples (500 mg) the detection limits were 0.7 ng g−1 (CVAAS) and 0.4 ng g−1 (CVAFS). After pyrolysis, detection limits of 3.5 ng g−1 and 1.6 ng g−1 for CVAAS and CVAFS, respectively, were obtained for a 10 mg sample. Pyrolysis can only be applied when the organic content
of the sample is not too high. Accurate results were obtained for 8 certified reference materials of both environmental and
biological origin. In addition, a real sludge sample was analysed.
Author for correspondence. E-mail: richard.dams@rug.ac.be
Received September 18, 2002; accepted December 3, 2002
Published online May 5, 2003 相似文献
19.
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
20.
Vega D Agüí L González-Cortés A Yáñez-Sedeño P Pingarrón JM 《Analytical and bioanalytical chemistry》2007,389(3):951-958
The voltammetric behaviour and amperometric detection of tetracycline (TC) antibiotics at multi-wall carbon nanotube modified
glassy carbon electrodes (MWCNT-GCE) are reported. Cyclic voltammograms of TCs showed enhanced oxidation responses at the
MWCNT-GCE with respect to the bare GCE, attributable to the increased active electrode surface area. Hydrodynamic voltammograms
obtained by flow-injection with amperometric detection at the MWCNT-GCE led us to select a potential value E
det = +1.20 V. The repeatability of the amperometric responses was much better than that achieved with bare GCE (RSD ranged from
7 to 12%), with RSD values for i
p of around 3%, thus demonstrating the antifouling capability of MWCNT modified electrodes. An HPLC method with amperometric
electrochemical detection (ED) at the MWCNT-GCE was developed for tetracycline, oxytetracycline (OTC), chlortetracycline and
doxycycline (DC). A mobile phase consisting of 18:82 acetonitrile/0.05 mol L−1 phosphate buffer of pH 2.5 was selected. The limits of detection ranged from 0.09 μmol L−1 for OTC to 0.44 μmol L−1 for DC. The possibility to carry out multiresidue analysis is demonstrated. The HPLC-ED/MWCNT-GCE method was applied to the
analysis of fish farm pool water and underground well water samples spiked with the four TCs at 2.0 × 10−7 mol L−1. Solid-phase extraction was accomplished for the preconcentration of the analytes and clean-up of the samples. Recoveries
ranged from 87 ± 6 to 99 ± 3%. Under preconcentration conditions, limits of detection in the water samples were between 0.50
and 3.10 ng mL−1. 相似文献