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1.
A novel analytical method is presented for the determination of chlorophenols in water. This method involves pre-concentration by solid-phase microextraction (SPME) and an external desorption using a micellar medium as desorbing agent. Final analysis of the selected chlorophenols compounds was carried out by high-performance liquid chromatography (HPLC) with diode array detection (DAD). Optimum conditions for desorption, using the non-ionic surfactant polyoxyethylene 10 lauryl ether (POLE), such as surfactant concentration and time were studied. A satisfactory reproducibility for the extraction of target compounds, between 6 and 15%, was obtained, and detection limits were in the range of 1.1-5.9ngmL(-1). The developed method is evaluated and compared with the conventional one using organic solvent as a desorbing agent. The method was successfully applied to the determination of chlorophenols in water samples from different origin. This study has demonstrated that solid-phase microextraction with micellar desorption (SPME-MD) can be used as an alternative to conventional SPME method for the extraction of chlorophenols in water samples. 相似文献
2.
López Monzón A Vega Moreno D Torres Padrón ME Sosa Ferrera Z Santana Rodríguez JJ 《Analytical and bioanalytical chemistry》2007,387(6):1957-1963
Solid-phase microextraction (SPME) coupled with high-performance liquid chromatography (HPLC) with fluorescence detection
was optimized for extraction and determination of four benzimidazole fungicides (benomyl, carbendazim, thiabendazole, and
fuberidazole) in water. We studied extraction and desorption conditions, for example fiber type, extraction time, ionic strength,
extraction temperature, and desorption time to achieve the maximum efficiency in the extraction. Results indicate that SPME
using a Carboxen–polydimethylsiloxane 75 μm (CAR–PDMS) fiber is suitable for extraction of these types of compound. Final
analysis of benzimidazole fungicides was performed by HPLC with fluorescence detection. Recoveries ranged from 80.6 to 119.6
with RSDs below 9% and limits of detection between 0.03 and 1.30 ng mL−1 for the different analytes. The optimized procedure was applied successfully to the determination of benzimidazole fungicides
mixtures in environmental water samples (sea, sewage, and ground water). 相似文献
3.
Torres Padrón ME Mahugo Santana C Sosa Ferrera Z Santana Rodríguez JJ 《Journal of chromatographic science》2008,46(4):325-331
Eleven phenolic compounds considered by the Environmental Protection Agency to be priority pollutants are extracted and determined in different water samples. The method involves the extraction and clean-up step of target compounds by solid-phase microextraction and micellar desorption (SPME-MD) and a second step of determination by liquid chromatography with diode array detection. Different fibers and surfactants are evaluated for the analysis of these target analytes in water samples. In the optimum conditions for the SPME process, recoveries for the target compounds are between 80% and 109%; relative standard deviations are lower than 10%, and detection limits are in the range 0.3-3.5 ng/mL. The main advantages of this method are the combination of time and efficiency, safety, and an environmentally friendly process for sample extraction prior to instrumental determination. This demonstrates that SPME-MD can be used as an alternative to traditional methods for the extraction and determination of priority phenolic compounds in natural waters from different origins. 相似文献
4.
Summary A method for determination of trace amounts of the pesticides tebufenpyrad and oxadiazon, previous solid-phase microextraction
(SPME), was developed using gas chromatographymass spectrometry and selected ion monitoring (GC-MS; SIM). Both pesticides
were extracted with a fused silica fiber coated with 100 μm polydimethylsiloxane. The effects of pH ionic strength, sample
volume, extraction and desorption times as well as extraction temperature were studied. The linear concentration range of
application was 0.5–250 ng mL−1 for both compounds, with a detection limit of 0.06 ng mL−1 for tebufenpyrad and 0.02 ng mL−1 for oxadiazon. SPME-GC-MS analysis yielded good reproducibility (RSD between 7.5–10.1%). It was used to check the eventual
existence of tebufenpyrad and oxadiazon above this limit in water and soil samples from Granada (Spain) as well as in human
urine samples. The method validation was completed with spiked matrix samples. It can be applied as a monitoring tool for
water, soil and urine in the investigation of environmental and occupational exposure to tebufenpyrad and oxadiazon. 相似文献
5.
A simple, rapid, and sensitive method using in-tube solid-phase microextraction (in-tube SPME) based on poly(methacrylic acid–ethylene
glycol dimethacrylate) (MAA–EGDMA) monolith coupled to HPLC with fluorescence and UV detection was developed for the determination
of five fluoroquinolones (FQs). Ofloxacin (OFL), norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (ENRO), and sarafloxacin
(SARA) can be enriched and determined in the spiked eggs and albumins. CIP/ENRO in eggs and albumins of ENRO-treated hens
were also studied using the proposed method. Only homogenization, dilution, and centrifugation were required before the sample
was supplied to the in-tube microextraction, and no organic solvents were consumed in the procedures. Under the optimized
extraction conditions, good extraction efficiency for the five FQs was obtained with no matrix interference in the process
of extraction and the subsequent chromatographic separation. The detection limits (S/N=3) were found to be 0.1–2.6 ng g−1 and 0.2–2.4 ng g−1 in whole egg and egg albumin, respectively. Good linearity could be achieved over the range 2–500 ng mL−1 for the five FQs with regression coefficients above 0.9995 in both whole egg and albumin. The reproducibility of the method
was evaluated at three concentration levels, with the resulting relative standard deviations (RSDs) less than 7%. The method
was successfully applied to the analysis of ENRO and its primary metabolite CIP in the eggs and albumins of ENRO-treated hens. 相似文献
6.
Prieto A Zuloaga O Usobiaga A Etxebarria N Fernández LA 《Analytical and bioanalytical chemistry》2008,390(2):739-748
A method for the determination of polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyls (PBBs) in water samples
is proposed. The method involving stir bar sorptive extraction (SBSE) and thermal desorption followed by gas chromatography
coupled with mass spectrometry was optimised using statistical design of experiments. In the first place, the influence of
different polydimethylsiloxane stir bars was studied. A Plackett–Burman design was chosen to estimate the influence of five
factors on the efficiency of the SBSE process: desorption time (5–10 min), desorption temperature (250–300 °C), desorption
flow (50–100 mL min−1), cryofocusing temperature (-130 to 40 °C) and vent pressure (0–12.8 psi). Afterwards, two central composite designs were
used to find the optimal process settings that were applied to the optimisation of both desorption and extraction efficiency.
In the case of the desorption parameters, long desorption times (10 min) and desorption flows lower than 70 mL min-1 yielded the best signals for the majority of compounds. However, different behaviour among the analytes was observed for
the vent pressure and we decided to fix it at an intermediate value (7 psi). In the case of extraction parameters, the sample
volume and the addition of NaCl did not have a significant effect, while the addition of methanol yielded better extraction
responses. Remarkable recovery (82–106%) and repeatability (less than 18%) were attained. Furthermore, excellent regression
coefficients (r
2 = 0.991–0.999) and low detection limits (1.1–6.0 ng L−1) were also achieved for the congeners studied. The proposed method was applied to the analyses of PBDEs and PBBs in waters
from the Basque Country, Spain. 相似文献
7.
Benito-Peña E Martins S Orellana G Moreno-Bondi MC 《Analytical and bioanalytical chemistry》2009,393(1):235-245
A novel water-compatible molecularly imprinted polymer (MIP), prepared with enrofloxacin (ENR) as the template, has been optimised
for the selective extraction of fluoroquinolone antibiotics in aqueous media. The results of a morphological characterisation
and selectivity tests of the polymer material for ENR and related derivatives are reported. High affinity for the piperazine-based
fluoroquinolones marbofloxacin, ciprofloxacin, norfloxacin and ofloxacin was observed, whereas no retention was found for
nonrelated antibiotics. Various parameters affecting the extraction efficiency of the polymer have been optimised to achieve
selective extraction of the antibiotics from real samples and to reduce nonspecific interactions. These findings resulted
in a MISPE/HPLC-FLD method allowing direct extraction of the analytes from aqueous samples with a selective wash using just
50% (v/v) organic solvent. The method showed excellent recoveries and precision when buffered urine samples fortified at five
concentration levels (25–250 ng mL−1 each) of marbofloxacin, ciprofloxacin, norfloxacin, enrofloxacin and sarafloxacin were tested (53–88%, RSD 1–10%, n = 3). Moreover, the biological matrix of the aqueous samples did not influence the preconcentration efficiency of the fluoroquinolones
on the MIP cartridges; no significant differences were observed between the recovery rates of the antibiotics in buffer and
urine samples. The detection limits of the whole process range between 1.9 and 34 ng mL–1 when 5-mL urine samples are processed. The developed method has been successfully applied to preconcentration of norfloxacin
in urine samples of a medicated patient, demonstrating the ability of the novel MIP for selective extraction of fluoroquinolones
in urine samples. 相似文献
8.
Based on polyethylene glycol modified single-walled carbon nanotubes, a novel sol–gel fiber coating was prepared and applied
to the headspace microextraction of chlorinated organic carriers (COCs) in textiles by gas chromatography-electron capture
detection. The preparation of polyethylene glycol modified single-walled carbon nanotubes and the sol–gel fiber coating process
was stated and confirmed by infrared spectra, Raman spectroscopy, and scanning electron microscopy. Several parameters affecting
headspace microextraction, including extraction temperature, extraction time, salting-out effect, and desorption time, were
optimized by detecting 11 COCs in simulative sweat samples. Compared with the commercial solid-phase microextraction fibers,
the sol–gel polyethylene glycol modified single-walled carbon nanotubes fiber showed higher extraction efficiency, better
thermal stability, and longer life span. The method detection limits for COCs were in the range from 0.02 to 7.5 ng L−1 (S/N = 3). The linearity of the developed method varied from 0.001 to 50 μg L−1 for all analytes, with coefficients of correlation greater than 0.974. The developed method was successfully applied to the
analysis of trace COCs in textiles, the recoveries of the analytes indicated that the developed method was considerably useful
for the determination of COCs in ecological textile samples. 相似文献
9.
C. Giachetti 《Chromatographia》1998,48(5-6):443-449
Summary Low amounts of triethanolamine, collected in ORBO 53 tubes during air sampling, required the development of a very sensitive
method for determination. After desorption and silylation reaction with trimethylsilyl imidazole/trimethyl chlorosilane, the
derivative was analyzed by gas chromatography-mass spectrometry on an Ultra 2 silica capillary column in single ion monitoring
mode (retention time: about 6 min). The method has a detection limit of 1–2 pg with a desorption efficiency of about 81%.
Linearity of response was ascertained in the ranges 10–100 ng and 100–1000 ng. Short-term method validation was carried out
by intra- and inter-day assays on three amounts for each reference calibration curve. All results satisfied the pre-defined
acceptance criteria. In general, the whole procedure was easily performed and was appropriate for our needs. Breakthrough
volume was appropriate for our needs. Breakthrough volume was determined on authentic samples and was about 40–60 L, using
a flow rate of 1 L·min−1. The amounts of triethanolamine found in the samples ranged from 150 to 250 ng (about 2.5–4.2 μg·m−3). 相似文献
10.
A rapid and reliable method based on micellar electrokinetic capillary chromatography has been developed for the determination
of dexamethasone in cosmetics. Effects of buffer composition, concentration and pH, the detection wavelength, separation voltage,
and injection time were systematically investigated. The optimum conditions were: 30 mM borax buffer containing 20 mM sodium
dodecyl sulfate at pH 9.0, detection at 254 nm, injection time 10 s at a height of 10 cm, and a separation voltage of 15 kV.
Under these conditions, the analysis of dexamethasone in cosmetics was carried out within 6 min. The method was validated
for stability, precision, linearity and accuracy. Excellent linearity was obtained in the range of 50–1,000 μg mL−1, and acceptable precision, in intra-day and inter-day analysis, was also obtained with relative standard deviation in the
range of 0.19–0.86 and 2.50–4.90% for migration time and peak area ratio, respectively. The method was used to analyse eight
cosmetic samples purchased locally. 相似文献
11.
M. Gil-Agustí M. E. Capella-Peiró A. Martinavarro-Domínguez J. Esteve-Romero 《Chromatographia》2003,57(1-2):51-57
Summary A procedure has been developed for the determination, in <12 min, of several stimulants (amphetamine, ephedrine, methoxyphenamine,
phenylephrine and phenylpropanolamine) in spiked urine samples after direct injection, using a hybrid micellar mobile phase
of 0.15 M sodium dodecyl sulfate and 3% pentanol at pH 7, on a C18 column with UV detection. Recoveries were 94–102% and limits of detection 4.5 ng·mL−1 for methoxyphenamine and 0.39 μg·mL−1 for amphetamine, similar to those obtained for aqueous solutions. Linearity reached 0.99 and intermediate precision was <8.4
and 5.3, for the two different concentrations tested. 相似文献
12.
Chunxia Wu Huimin Liu Weihua Liu Qiuhua Wu Chun Wang Zhi Wang 《Analytical and bioanalytical chemistry》2010,397(6):2543-2549
A simple dispersive liquid–liquid microextraction based on solidification of floating organic droplet coupled with high-performance
liquid chromatography–diode array detection was developed for the determination of five organophosphorus pesticides (OPs)
in water samples. In this method, the extraction solvent used is of low density, low toxicity, and proper melting point near
room temperature. The extractant droplet could be collected easily by solidifying it in the lower temperature. Some important
experimental parameters that affect the extraction efficiencies were optimized. Under the optimum conditions, the calibration
curve was linear in the concentration range from 1 to 200 ng mL−1 for the five OPs (triazophos, parathion, diazinon, phoxim, and parathion-methyl), with the correlation coefficients (r) varying from 0.9991 to 0.9998. High enrichment factors were achieved ranging from 215 to 557. The limits of detection were
in the range between 0.1 and 0.3 ng mL−1. The recoveries of the target analytes from water samples at spiking levels of 5.0 and 50.0 ng mL−1 were 82.2–98.8% and 83.6–104.0%, respectively. The relative standard deviations fell in the range of 4.4% to 6.3%. The method
was suitable for the determination of the OPs in real water samples. 相似文献
13.
Ankita Shukla Sunil Kumar Sanghi V. Sorna Gowri Vishal Kumar Baderia Sushma Lamba Deepesh Kumar Singh 《Journal of Analytical Chemistry》2011,66(3):296-300
A simple and rapid method has been developed for the determination of biogenic amines in lake water using micellar electrokinetic
chromatography with fluorescence detection. Separation of fluorescamine derivatized biogenic amines was accomplished by using
borate buffer of pH 9.5 containing 40 mM of sodium dodecyl sulphate. The method has been optimized with respect to fluorescamine
concentration, reaction pH, reaction time, separation voltage and injection time. Detection was performed by using UG-11 excitation
filter and 495 nm emission filter. The proposed method for histamine, tyramine and dopamine allowed their separation within
2 min with detection limits in nM range. The interday and intraday reproducibility of peak areas were less than 6.5%. Recovery
of spiked samples was 95.76–116.31%. 相似文献
14.
Zhao RS Diao CP Wang X Jiang T Yuan JP 《Analytical and bioanalytical chemistry》2008,391(8):2915-2921
This paper describes a novel, simple and environmentally friendly method for rapid determination of the amide herbicides metoalchlor,
acetochlor, and butachlor. It is based on dispersive liquid-liquid microextraction and gas chromatography–mass spectrometry.
Factors that may influence the enrichment efficiency, such as type and volume of extraction solvent, type and volume of dispersive
solvent, extraction time, and content of NaCl, were investigated and optimized in detail. Under the optimum conditions, the
limits of detection of metoalchlor, acetochlor, and butachlor were 0.02, 0.04, and 0.003 μg L−1, respectively. The experimental results indicated that there was linearity over the range 0.1–50 μg L−1 and good reproducibility with relative standard deviations over the range 1.6–3.0% (n = 5). The proposed method has been applied for the analysis of real-world water samples, and satisfactory results were achieved.
Average recoveries of spiked herbicides were in the range 80.3–108.8%. All of these indicated that the developed method would
be an efficient method for simultaneous determination of the three herbicides in environmental water samples. 相似文献
15.
Sandra Babić Dragana Mutavdžić Pavlović Danijela Ašperger Martina Periša Mirta Zrnčić Alka J. M. Horvat Marija Kaštelan-Macan 《Analytical and bioanalytical chemistry》2010,398(3):1185-1194
An analytical method for multi-class pharmaceuticals determination in wastewater has been developed and validated. Target
compounds were: sulfonamides (sulfadiazine, sulfaguanidine, sulfamethazine, sulfamethoxazole), fluoroquinolones (ciprofloxacin,
enrofloxacin, norfloxacin), diaminopyrimidine (trimethoprim), anaesthetic (procaine), anthelmintic (praziquantel and febantel),
and macrolide (roxithromycin). The method involves pre-concentration and clean-up by solid-phase extraction (SPE) using Strata-X
extraction cartridges at pH 4.0. Target analytes were identified and quantitatively determined by liquid chromatography–tandem
mass spectrometry using multiple reaction monitoring (MRM). Recoveries were higher than 50% with relative standard deviation
(RSD) below 18.3% for three concentrations. Only for sulfaguanidine was low recovery obtained. Matrix effect was evaluated
using matrix-matched standards. The method detection limit (MDL) was between 0.5 and 5 ng L−1 in spiked water samples. The precision of the method, calculated as relative standard deviation, ranged from 0.5 to 2.0%
and from 1.4 to 8.3 for intra-day and inter-day analysis, respectively. The described analytical method was used for determination
of pharmaceuticals in effluent wastewaters from the pharmaceutical industry. 相似文献
16.
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
17.
Ru-Song Zhao Xia Wang Jing Sun Shan-Shan Wang Jin-Peng Yuan Xi-Kui Wang 《Analytical and bioanalytical chemistry》2010,397(4):1627-1633
A novel and environmentally friendly microextraction method, termed ionic liquid dispersive liquid-phase microextraction (IL-DLPME),
has been developed for rapid enrichment of triclosan and triclocarban before analysis by high-performance liquid phase chromatography–electrospray
tandem mass spectrometry (HPLC–ESI-MS–MS). Instead of using toxic organic solvents, an ionic liquid was used as a green extraction
solvent. This also avoided the instability of the suspending drop in single-drop liquid-phase microextraction, and the heating
and cooling step in temperature-controlled ionic liquid dispersive liquid phase microextraction. Factors that may affect the
enrichment efficiency, for example volume of ionic liquid, type and volume of dispersive solvent, pH, extraction time, and
NaCl content were investigated in detail and optimized. Under optimum conditions, linearity of the method was observed over
the range 0.2–12 μg L−1 for triclocarban and 1–60 μg L−1 for triclosan with correlation coefficients ranging from 0.9980 to 0.9990, respectively. The sensitivity of the proposed
method was found to be excellent, with limits of detection in the range 0.040–0.58 μg L−1 and precision in the range 7.0–8.8% (RSD, n = 5). This method has been successfully used to analyze real environmental water samples and satisfactory results were achieved.
Average recoveries of spiked compounds were in the range 70.0–103.5%. All these results indicated that the developed method
would be a green method for rapid determination of triclosan and triclocarban at trace levels in environmental water samples. 相似文献
18.
A rapid method for the extraction and determination of 90Sr in natural water, plant and sediment samples was developed using extraction chromatography and dynamic reaction cell ICP–MS,
with O2 as a reaction gas. While isobaric interference from the stable isotope 90Zr was efficiently removed by this method, interferences produced from in-cell reactions with Fe+ and Ni+ required suppression by tuneable bandpass, and in sediments, additional chromatographic separation. Method detection limits
were 0.1 pg g−1 (0.5 Bq g−1), 0.04 pg g−1(0.2 Bq g−1), and 3 pg L−1 (5 Bq L−1) for sediments, plant and water samples, respectively, and 90Sr concentrations determined by ICP–MS were in good agreement with activities determined by Cerenkov counting and with certified
reference values. While mass spectrometric determination does not rival detection limits achievable by radiometric counting,
radiometric determination of 90Sr, a pure beta-emitter, is hindered by long analysis times (several weeks); the comparatively fast analysis achieved via
ICP–MS enables same-day preparation and analysis of samples, making this an important technique for the environmental monitoring
of areas contaminated by radioactivity. 相似文献
19.
Chen KY Yang TC Chang SY 《Journal of the American Society for Mass Spectrometry》2012,23(6):1157-1160
A novel method for the determination of macrolide antibiotics using dispersive liquid–liquid microextraction coupled to surface-assisted
laser desorption/ionization mass spectrometric detection was developed. Acetone and dichloromethane were used as the disperser
solvent and extraction solvent, respectively. A mixture of extraction solvent and disperser solvent were rapidly injected
into a 1.0 mL aqueous sample to form a cloudy solution. After the extraction, macrolide antibiotics were detected using surface-assisted
laser desorption/ionization mass spectrometry (SALDI/MS) with colloidal silver as the matrix. Under optimum conditions, the
limits of detection (LODs) at a signal-to-noise ratio of 3 were 2, 3, 3, and 2 nM for erythromycin (ERY), spiramycin (SPI),
tilmicosin (TILM), and tylosin (TYL), respectively. This developed method was successfully applied to the determination of
macrolide antibiotics in human urine samples. 相似文献
20.
Summary A gas chromatographic method for the determination of residues of Fosfomycin in chicken muscle samples has been developed.
Muscle samples were homogenised with TRIS buffer, containing phenylphosphonic acid (as internal standard) and Fosfomycin using
a tissue homogenizer. Afterwards, the samples were ultrafiltered and the ultrafiltrate was evaporated to dryness. A silylation
reagent for derivatization was used in order to reconstitute the residue. The linear concentration range of application was
10–150 μgg−1, with a detection and quantitation limit of 3.11 and 10 μgg−1, respectively. The method was efficient with a mean recovery of 87.83% from spiked muscle. The results obtained show that
gas chromatography is a useful method for the determination of Fosfomycin residues in chicken muscle samples. 相似文献