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1.
Asensio-Ramos M D'Orazio G Hernandez-Borges J Rocco A Fanali S 《Analytical and bioanalytical chemistry》2011,400(4):1113-1123
In this work, the simultaneous separation of a group of 12 pesticides (carbaryl, fensulfothion, mecoprop, fenamiphos, haloxyfop,
diclofop, fipronil, profenofos, fonofos, disulfoton, nitrofen, and terbufos) by nano-liquid chromatography with UV detection
is described. For the analyses, a 100 μm internal diameter capillary column packed with silica modified with phenyl groups
was used. Experimental parameters, including the use of a trapping column for increasing the sensitivity, were optimized and
validated. A preliminary study of the applicability of a rapid and practical dispersive solid-phase extraction (DSPE) procedure
was developed for the extraction of some of these pesticides (carbaryl, fensulfothion, fenamiphos, fipronil, profenofos, fonofos,
disulfoton, nitrofen, and terbufos) from Milli-Q water samples using multi-walled carbon nanotubes (MWCNTs). The method was
validated through a recovery study at three different levels of concentration, obtaining limits of detection in the range
0.016–0.067 μg/L (below European Union maximum residue limits) for the majority of the pesticides. In this work, MWCNTs were
reused up to five times, representing an important reduction of the waste of stationary phase. Furthermore, DSPE permitted
a clear diminution of the total sample treatment time with respect to conventional SPE. 相似文献
2.
López-Blanco C Gómez-Alvarez S Rey-Garrote M Cancho-Grande B Simal-Gándara J 《Analytical and bioanalytical chemistry》2006,384(4):1002-1006
The European Union specificies that drinking water can contain pesticide residues at concentrations of up to 0.1 μg/L each
and 0.5 μg/L in total, and that 1–3 μg/L of pesticides can be present in surface water, but the general idea is to keep discharges,
emissions and losses of priority hazardous substances close to zero for synthetic substances. Therefore, in order to monitor
pesticide levels in water, analytical methods with low quantification limits are required. The method proposed here is based
on solid phase extraction (SPE) followed by gas chromatography with a nitrogen–phosphorous detector (GC-NPD). During method
development, six organophosphate pesticides (azinphos-ethyl, chlorfenvinphos, chlorpyriphos, ethoprophos, fenamiphos and malathion)
and two organonitrogen pesticides (alachlor and deltamethrin) were considered as target analytes. Elution conditions that
could influence the efficiency of the SPE were studied. The optimized methodology exhibited good linearity, with determination
coefficients of better than 0.996. The analytical recovery for the target analytes ranged from 70 to 100%, while the within-day
precision was 4.0–11.5 %. The data also showed that the nature of the aqueous matrice (ultrapure, surface or drinking water)
had no significant effect on the recovery. The quantification limits for the analytes were found to be 0.01–0.13 μg/L (except
for deltamethrin, which was 1.0 μg/L). The present methodology is easy, rapid and gives better sensitivity than solvent drop
microextraction for the determination of organonitrogen and organophosphate pesticides in drinking water at levels associated
with the legislation. 相似文献
3.
Separation and determination of flavonoids and other phenolic compounds in cranberry juice by high-performance liquid chromatography 总被引:5,自引:0,他引:5
A HPLC method was developed for the separation and determination of flavonoid and phenolic antioxidants in cranberry juices. Free flavonoid and phenolic compounds were fractionated into neutral and acidic groups by means of a solid-phase extraction method, followed by subsequent HPLC separations. Combined flavonoids and phenolics were hydrolyzed by acid before HPLC analysis. This developed method provides a fast and high resolution of individual flavonoid and phenolic compounds. In cranberry fruit, flavonoids and phenolic acids exist predominantly in combined forms, such as glycosides and esters. A total of 400 mg of total flavonoids and phenolic compounds/l of sample was found in a freshly squeezed cranberry juice, which was distributed as about 44% of phenolic acids and 56% of flavonoids. Benzoic acid was the major phenolic compound. Major flavonoids in the freshly squeezed cranberry juice were quercetin and myricetin. 相似文献
4.
A. Martín-Esteban P. Fernández C. Cámara G. N. Kramer E. A. Maier 《Fresenius' Journal of Analytical Chemistry》1999,363(7):632-640
The preparation of a certified reference material of polar pesticides in freeze-dried water is described. The pesticides
selected were atrazine, simazine, carbaryl, propanil, linuron, fenamiphos and permethrin which were added to 6000 litres of
tap water at 50–80 μg · L–1 (200–320 μg · L–1 for permethrin) level in presence of NaCl (2.5 g · L–1) prior lyophilization. After the freeze-drying process the residue was rehomogenized, filled into amber glass bottles and
stored at –20 °C, +4 °C and +20 °C. All pesticides were determined by HPLC/diode array detector, except permethrin which was
determined by GC/ECD. The results obtained for atrazine, simazine, carbaryl, propanil, linuron and fenamiphos showed no within-
or between-bottle inhomogeneity, however the material was non-homogeneous for permethrin and therefore this was withdrawn
from further studies. With respect to the stability for over one year, all pesticides were stable at –20 °C. At +4 °C all
pesticides were stable for at least 9 months and at +20 °C the stability was demonstrated only during the first month of storage.
The content (mass fractions) of atrazine, simazine, carbaryl, propanil and linuron in freeze-dried water (CRM 606) was certified
by an interlaboratory testing and a certification campaign.
Received: 7 September 1998 / Revised: 13 November 1998 / Accepted: 21 November 1998 相似文献
5.
Atmospheric pressure glow discharge desorption mass spectrometry for rapid screening of pesticides in food 总被引:1,自引:0,他引:1
Jecklin MC Gamez G Touboul D Zenobi R 《Rapid communications in mass spectrometry : RCM》2008,22(18):2791-2798
Flowing afterglow atmospheric pressure glow discharge tandem mass spectrometry (APGD-MS/MS) is used for the analysis of trace amounts of pesticides in fruit juices and on fruit peel. The APGD source was rebuilt after Andrade et al. (Andrade et al., Anal. Chem. 2008; 80: 2646-2653; 2654-2663) and mounted onto a hybrid quadrupole time-of-flight mass spectrometer. Apple, cranberry, grape and orange juices as well as fruit peel and salad leafs were spiked with aqueous solutions containing trace amounts of the pesticides alachlor, atrazine, carbendazim, carbofuran, dinoseb, isoproturon, metolachlor, metolcarb, propoxur and simazine. Best limits of determination (LODs) of pesticides in the fruit juices were achieved for metolcarb (1 microg/L in apple juice), carbofuran and dinoseb (2 microg/L in apple juice); for the analysis of apple skin best LODs were 10 pg/cm(2) of atrazine, metolcarb and propoxur which corresponds to an estimated concentration of 0.01 microg/kg apple, taking into account the surface area and the weight of the apple. The measured LODs were within or below the allowed maximum residue levels (MRLs) decreed by the European Union (1-500 microg/kg for pesticides in fruit juice and 0.01-5 microg/kg for apple skin). No sample pretreatment (extraction, pre-concentration, chromatographic separation) was necessary to analyze these pesticides by direct desorption/ionization using APGD-MS and to identify them using MS/MS. This makes APGD-MS a powerful high-throughput tool for the investigation of very low amounts of pesticides in fruit juices and on fruit peel/vegetable skin. Copyright (c) 2008 John Wiley & Sons, Ltd. 相似文献
6.
R. Jeannot H. Sabik L. Amalric E. Sauvard S. Proulx B. Rondeau 《Chromatographia》2001,54(3-4):236-240
Summary A method has been developed for determination of twenty-four polar pesticides—nine organophosphorus pesticides, thirteen organonitrogen
compounds, and two triazine degradation products—in surface water. It entails extraction of the target pesticides from 1-L
water samples by solid-phase extraction (SPE), then gas chromatography (GC) with large-volume (40 μL) injection. Filtered
surface water, from the St Lawrence River in Canada and the River Loire and its tributaries in France, was extracted on cartridges
filled with 500 mg Carbopack B (120–400 mesh). Analysis was performed by gas chromatography with a thermionic specific detector
(GC-TSD) and a mass spectrometric (MS) detector. Overall percentage recoveries were satisfactory (>70%) for all target pesticides,
with precision below 10%. Detection limits were between 0.5 and 4 ng L−1. 相似文献
7.
Multiresidue determination of pesticides in juice by solid-phase extraction and gas chromatography-mass spectrometry 总被引:1,自引:0,他引:1
A multiresidue method based on solid-phase extraction was developed for the simultaneous determination of 50 pesticides in commercial juices. The extraction procedure was carried out in C18 columns preconditioned with acetonitrile and water. The subsequent elution of pesticides was performed with a mixture of hexane-ethyl acetate (1:1, v/v) prior to the determination by gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode (GC-MS-SIM), using one target and two qualifier ions. Standards were prepared spiking blank juice samples to counteract the observed matrix effect. Average recoveries for all the pesticides studied were higher than 91% with relative standard deviations lower than 9% in the concentration range of 0.02-0.1 μg/mL and the detection limits achieved ranged from 0.1 to 4.6 μg/L. The proposed method was applied to the analysis of these compounds in commercial juices and diazinon, ethion and procymidone were the pesticides encountered, although the levels found were very low. 相似文献
8.
Summary The stability of freeze-dried water samples spiked with eight agrochemicals (atrazine, simazine, linuron, carbaryl, propanil, fenitrothion, parathion and fenamiphos) were examined to evaluate their suitability as candidate reference materials for their determination in water samples. In addition, two different extraction procedures, liquid-liquid and supercritical fluid extraction, were compared for the isolation and trace enrichment of target analytes from freeze-dried water samples. Final analytical determinations were by gas chromatography-nitrogen phosphorus detection and electronic impact mass spectrometry, and by liquid chromatography-diode array detection. The whole methodology developed in this paper permitted the determination of pesticides spiked in water at levels varying from 0.03 to 6.9 g L–1. 相似文献
9.
E. W. J. Hooijschuur Ch. E. Kientz J. Dijksman U. A. Th. Brinkman 《Chromatographia》2001,54(5-6):295-301
Summary The potential of microcolumn liquid chromatography (μlC) and capillary electrophoresis (CE) with on-line, flame photometric
detection (FPD) in the P-selective mode has been studied for determination of polar P-containing pesticides, glyphosate and
its main metabolite, aminomethylphosphonic acid (AMPA), ethephon, fosetyl-aluminium and acephate. Acephate was determined
by reversed-phase μLLC-FPD using large-volume injections with peak compression, the other compounds were determined by μLC-FPD
and CE-FPD using simple, large-volume injection procedures to obtain limits of detection of 7.5-500 ng·mL−1 and 1.0 μ·mL−1, respectively. The methods showed acceptable repeatability and robustness and were successfully applied for rapid and selective
determination of pesticides in fruit, vegetable and water samples. 相似文献
10.
Tahereh Harsij Sani Mohammadreza Hadjmohammadi Mohammad Hossein Fatemi 《Journal of separation science》2020,43(7):1224-1231
Extraction and determination of three flavonoids (morin, quercetin, and kaempferol) were performed by dispersive magnetic solid phase extraction based on mixed hemi/ad‐micelles and high‐performance liquid chromatography with UV detection. The Fe3O4/SiO2 nanoparticles were synthesized and characterized by X‐ray diffraction, FTIR, scanning electron microscopy, and thermogravimetric analysis. Fe3O4/SiO2 nanoparticles coated with mixed hemi/ad‐micelles cetyltrimethyl ammonium bromide was applied as a sorbent and used for extraction of flavonoids. Effective parameters on the extraction recovery such as amount of magnetic nano particles, volume of cetyltrimethyl ammonium bromide solution with specific concentration, pH of sample solution, adsorption equilibrium time, volume of desorption solvent, and desorption times were evaluated and optimized using fractional factorial design and central composite design. Under the optimum condition limit of detection and linearity were 0.83, 2.7–500.0 for morin, 0.18, 0.7–500.0 for quercetin and, 0.37, 1.3–500.0 µg/L for kaempferol. The extraction recovery with relative standard deviation were 97.88, 1.94 for morin, 95.77, 0.80 for quercetin, and 93.35, 1.45 for kaempferol. The proposed method was applied for simultaneous extraction and determination of flavonoids in several fruit juices and vegetable samples. 相似文献
11.
Dolores Barranco Martínez María Martínez Galera Piedad Parrilla Vázquez M. Dolores Gil García 《Chromatographia》2007,66(7-8):533-538
Liquid chromatography with electrospray mass spectrometry (LC–ESI-MS) instrumentation equipped with a single quadrupole mass
filter has been used to determine several benzoylphenylurea insecticides (diflubenzuron, triflumuron, hexaflumuron, lufenuron
and flufenoxuron). Chromatographic and MS parameters were optimised to obtain the best sensitivity and selectivity for all
pesticides. Solid-phase extraction (SPE) using C18 cartridges was applied for preconcentration of pesticide trace levels in river water samples. Recoveries of benzoylphenylurea
pesticides from spiked river water (0.01 and 0.025 μg L−1) were between 73 and 110% and detection limits were between 3.5 and 7.5 ng L−1. The applicability of the method to the determination of benzoylphenylurea insecticides in spiked cucumber, green beans,
tomatoes and aubergines was evaluated. Samples were extracted into dichloromethane without any clean-up step. The limits of
detection ranged from 1.0 to 3.2 ng mL−1 (0.68 and 2.13 μg kg−1 in the vegetable samples). Mean recoveries ranged from 79 to 114% at spiking levels of 0.01 and 0.03 mg kg−1. The method was applied to determine traces of benzoylphenylureas in both river water and vegetable samples with precision
values lower than 10%. Interferences due to the matrix effect were overcome using matrix-matched standards. 相似文献
12.
Nicoleta Simona Vedeanu Dana Alina Magdas Laura Bolojan Grigore Damian 《Chemical Papers》2012,66(6):612-616
Antioxidant status of foods, plant, or fruit products is generally characterized by means of spectroscopic methods. Methods
like HPLC, UV-VIS, or MS spectroscopy are used to understand the chemical and physical properties of different samples, and
also EPR spectroscopy seems to be a valuable tool to characterize antioxidant activity of juice beverages. In this technique,
certain antioxidants present in fruit juices interact with free radicals interrupting the chain reaction that can possibly
damage essential molecules. Recording the EPR signal decay caused by the reaction with a natural or artificial reducing agent,
it is possible to draw conclusions about the antioxidant capability of materials. IRMS is a powerful tool to distinguish between
an authentic fruit juice and a juice obtained by concentrate dilution. This technique allows also the detection of commercial
C4 cane or corn derived sugar syrups in C3 fruit juices. In the present study, four commercial fruit juices were investigated using stable isotope measurements (oxygen,
hydrogen, and carbon) and EPR measurements in order to check the correct labeling in the Romanian markets and to compare antioxidant
activity of the studied juices and the reference. It was proven that the number of paramagnetic species decreases in time
with different reaction rates and this was correlated with the antioxidant activity of the studied juices. Stable isotope
ratio measurements have demonstrated that the fruit juices studied were reconstructed from concentrates with tap water, according
to their label. 相似文献
13.
Summary Two procedures, based on large-volume injection with a programmed-temperature vaporizer (PTV), have been developed for the
determination of several triazine and organophosphorus pesticides. The use of PTV for injection in gas chromatography (GC)
has enabled the introduction of up to 200 μL sample extract into the GC, thus increasing the sensitivity of the method. PTV
injection has been combined off-line with two different microextraction procedures—liquid-liquid partition and solid-phase
extraction.
A simple and rapid off-line liquid-liquid microextraction procedure (5 mL water/1 mL methyltert-butyl ether) was applied to surface water samples spiked at levels between 0.01 and 5μg L−1. Recoveries of the overall procedure were >80% and the precision was better than 15%. Detection limits were <30 ngL−1 from 200-μL injections in GC-NPD analysis of triazines and GC-FPD analysis of organophosphorus pesticides. Off-line automated
solid-phase extraction with C18 cartridges has been applied to water samples (50 mL) spiked at 0.01, 0.1 and 1 μg L−1. The overall procedure was satisfactory (recoveries >80% and coefficients of variation <12%) and the limits of detection
ranged from 1 to 9 ng L−1.
Finally, several surface water samples were anlysed, and triazine herbicides were detected at concentrations of approx. 0.1–0.2
μg L−1. The results were similar to those obtained by conventional solvent extraction then GC-MSD after splitless injection of 2
μL. 相似文献
14.
Trace determination of sulfonylurea herbicides in water and grape samples by capillary zone electrophoresis using large volume sample stacking 总被引:1,自引:0,他引:1
Carolina Quesada-Molina Monsalud del Olmo-Iruela Ana M. García-Campaña 《Analytical and bioanalytical chemistry》2010,397(6):2593-2601
A sensitive and reliable method using capillary zone electrophoresis with UV-diode array detection has been developed and
validated for trace determination of residues of sulfonylurea herbicides in environmental water samples and grapes from different
origins. The analytes included are triasulfuron, rimsulfuron, flazasulfuron, metsulfuron-methyl, and chlorsulfuron. Optimum
separation has been achieved on a 48.5-cm × 50-μm (effective length 40 cm) bubble cell capillary using 90 mM ammonium acetate
buffer, pH 4.8, by applying a voltage of 20 kV at 25 °C and using p-aminobenzoic acid as the internal standard. In order to
increase sensitivity, large volume sample stacking with polarity switching has been applied as on-line preconcentration methodology.
For water samples, a solid-phase extraction (SPE) procedure based on the use of Oasis HLB cartridges was applied for off-line
preconcentration and cleanup. For grape samples, the SPE procedure was achieved with C18 sorbent, after extraction of the compounds with MeOH:H2O (1:1) by sonication. The limits of detection for the studied compounds were between 0.04 and 0.12 μg/L for water samples
and 0.97 and 8.30 μg/kg in the case of grape samples, lower in all cases than the maximum residue limits permitted by the
EU for this kind of food. The developed methodology has demonstrated its suitability for the monitoring of these residues
in environmental water and grape samples with high sensitivity, precision, and satisfactory recoveries. 相似文献
15.
A method involving simultaneous extraction and sample clean-up procedure: hollow fiber sorptive microextraction, coupled with
gas chromatography–mass spectrometric detection for quantification of seven organochlorine pesticides in Radix et Rhizoma
Rhei is described. SiO2 hollow fiber with porous structure was synthesized for the first time. The internal diameter of SiO2 hollow fiber is 380 μm and average wall thickness is 100 μm. Aggregated SiO2 particles deposited on the surface of the hollow fiber in a regular array lead to porous structure. SiO2 hollow fiber was applied to the determination of organochlorine pesticides in Radix et Rhizoma Rhei to avoid sample clean-up
and minimize the matrix effects. Extraction solvent, extraction temperature and equilibration time were optimized. Fiber to
fiber repeatability over the concentration ranges were less than 10%. Recoveries were satisfactory (between 63% and 115%)
for most of organochlorine pesticides at spiking levels. Furthermore, the proposed method was also applied to determine seven
organochlorine pesticides in 43 commercial Radix et Rhizoma Rhei samples, in which the selected pesticides were found in eight
samples. The results have been further confirmed by solvent extraction methods according to China Pharmacopoeia (2005). 相似文献
16.
A new analytical method for the simultaneous determination of 90 pesticides in fruit juices by ultra performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) has been developed and validated. Extraction was performed with acetonitrile, applying QuEChERS methodology, and the extracts were analyzed without any further clean-up step, providing better results than solid phase extraction (SPE) procedure. Before chromatographic step, extracts were diluted with water (1:1) in order to obtain good peak shapes. Several chromatographic conditions were evaluated in order to achieve a fast separation in Multiple Reaction Monitoring (MRM) mode, obtaining a run time of only 11 min. Matrix effect was studied for different types of fruit juices (peach, orange, pineapple, apple and multifruit), indicating that multifruit juice can be selected as representative matrix for routine analysis of these food commodities. Pesticides were quantified using matrix-matched calibration with recoveries between 70.4 and 108.5% and relative standard deviation lower than 20%. Limits of quantification were lower than 5 microg L(-1) in all the cases. The developed procedure was applied to commercial fruit juices, detecting carbendazim, cyprodinil and thiabendazol in a few samples. 相似文献
17.
Torres Padrón ME Sosa Ferrera Z Santana Rodríguez JJ 《Analytical and bioanalytical chemistry》2006,386(2):332-340
A solid-phase microextraction (SPME) procedure using two commercial fibers coupled with high-performance liquid chromatography
(HPLC) is presented for the extraction and determination of organochlorine pesticides in water samples. We have evaluated
the extraction efficiency of this kind of compound using two different fibers: 60-μm polydimethylsiloxane–divinylbenzene (PDMS-DVB)
and Carbowax/TPR-100 (CW/TPR). Parameters involved in the extraction and desorption procedures (e.g. extraction time, ionic
strength, extraction temperature, desorption and soaking time) were studied and optimized to achieve the maximum efficiency.
Results indicate that both PDMS-DVB and CW/TPR fibers are suitable for the extraction of this type of compound, and a simple
calibration curve method based on simple aqueous standards can be used. All the correlation coefficients were better than
0.9950, and the RSDs ranged from 7% to 13% for 60-μm PDMS-DVB fiber and from 3% to 10% for CW/TPR fiber. Optimized procedures
were applied to the determination of a mixture of six organochlorine pesticides in environmental liquid samples (sea, sewage
and ground waters), employing HPLC with UV-diode array detector. 相似文献
18.
Summary Gas chromatography of polychlorinated biphenyls and chlorinated pesticides in water samples has been performed after adsorption
from a 50–250 mL sample on to a cartridge containing 100 mg cyanopropyl-bonded porous silica. The PCBs are desorbed with 500
μL ethyl acetate, which is concentrated and analysed by gas chromatography with electron-capture detection (GC-ECD).
The average recovery of 1 ppb PCB congeners at from distilled water and from Marta river water is ≥95% (standard deviation
≤2.5). The average recovery of 20 ppb Aroclor 1260 from Marta river water was ≥91% (standard deviation ≤3.5).
In the separation of the PCBs from the chlorinated pesticides only aldrin, heptachlor and 4,4′-DDD are adsorbed with the PCBs
by the CN Sep-Pak cartridge. The method proposed is rapid, simple and reproducible. 相似文献
19.
Ramešová S Sokolová R Degano I Bulíčková J Zabka J Gál M 《Analytical and bioanalytical chemistry》2012,402(2):975-982
The natural flavonoid compounds quercetin (3,3′,4′,5,7-pentahydroxyflavone) and luteolin (3′,4′,5,7-tetrahydroxyflavone) are
important bioactive compounds with antioxidative, anti-allergic, and anti-inflammatory properties. However, both are unstable
when exposed to atmospheric oxygen, which causes degradation and complicates their analytical determinations. The oxidative
change of these flavonoids was observed and followed by UV–visible spectrophotometry, both in aqueous and ethanolic solutions.
The distribution of the degradation products in aqueous media was monitored by LC–MS and LC–DAD analysis. The amounts of oxidative
reaction products increase with the exposure time. The oxidative degradation reduces the pharmacological efficiency of these
antioxidants and renders analytical determination inaccurate. The oxidative changes in flavonoid test solutions can explain
the inconsistent dissociation constants reported in the literature. Dissociation constants of quercetin and luteolin were
determined both by alkalimetric titration and by UV–visible spectrophotometry under deaerated conditions. The values pK
1 = 5.87 ± 0.14 and pK
2 = 8.48 ± 0.09 for quercetin, and pK
1 = 5.99 ± 0.32 and pK
2 = 8.40 ± 0.42 for luteolin were found. 相似文献
20.
Influence of extraction methods on stability of flavonoids 总被引:1,自引:0,他引:1
Biesaga M 《Journal of chromatography. A》2011,1218(18):2505-2512
The LC-MS/MS was applied for the determination of flavonoids' stability under four types of solvent extraction methods (reflux heating, sonication, maceration and microwave) from maize samples. The 11 flavonoids belong to different groups: flavonols (kaempferol, myricetin, rhamnetin, quercetin, rutin), flavanones (naringenin, naringin, hesperedin), flavones (apigenin, luteolin), isoflavones (genistein) were studied. The effect of the degradation of flavonoids depended on extraction mode and chemical structure. The smallest decomposition was observed by heated reflux extraction procedure within 30 min in water bath and by microwave assisted extraction under 160 W during 1 min. The decomposition for flavonoids depends on number of substituents in flavonoid molecule. The most unstable compound (recovery below 50%) in tested condition was myricetin. The higher number of hydroxyl groups promote degradation of flavonoids, whereas sugar moiety and methoxyl groups protect flavonoids of degradation during microwave and ultrasonic assisted extraction. 相似文献