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1.
In this work, a new method for the determination in white wines of 12 pesticides widely used in vine cultivars (namely, carbendazim, pirimicarb, metalaxyl, pyrimethanil, procymidone, nuarimol, azoxystrobin, tebufenozide, fenarimol, benalaxyl, penconazole, and tetradifon) using solid-phase microextraction (SPME) and MEKC with diode-array detection (DAD) was developed. The MEKC buffer consisted of 100 mM sodium tetraborate and 30 mM SDS at pH 8.5 with 6% v/v 1-propanol. Reversed-electrode polarity stacking mode (REPSM) was applied as on-line preconcentration strategy. In order to carry out an effective and sensitive determination of these pesticides in wine samples, an off-line SPME procedure was optimized by means of an experimental design. After studying the extraction performance of different SPME coatings, PDMS/divinylbenzene (PDMS/DVB) fibers were found the most appropriate for the extraction of most of these pesticides. Carbendazim and metalaxyl could not be extracted from wine samples. Calibration curves for extracted standards and fortified white wines were studied in order to determine the presence of a matrix effect. The combination of both preconcentration procedures (SPME and REPSM) allowed the determination of ten of these pesticides in white wines at concentrations between 0.054 and 0.113 mg/L. (i.e., levels well below the maximum residue limits (MRLs) allowed for these compounds in wine grapes). Ten homemade wines were they analyzed with the optimized method demonstrating the usefulness of the proposed procedure.  相似文献   

2.
In this work, the analysis of a group of four fungicides (pyrimethanil, nuarimol, procymidone and cyprodinil) and one insecticide (pirimicarb) by micellar electrokinetic chromatography (MEKC) with UV detection using the on-line preconcentration strategy called reversed electrode polarity stacking mode (REPSM) is proposed. After optimisation, an adequate separation electrolyte for the separation and stacking of these pesticides was obtained which consisted of 100 mM borate, 60 mM sodium dodecyl sulphate (SDS), at pH 9.0 and 2% 2-propanol. The use of this running buffer together with the REPSM preconcentration method provided limits of detection (LODs) between 38.3 and 241 microg/L. In order to apply the developed methodology for the analysis of these pesticides in wine samples, several off-line preconcentration strategies (mainly, solid-phase extraction, SPE, and solid-phase microextraction, SPME) were tested. Although the use of a SPE procedure, optimized in this work for water samples, using Oasis HLB cartridges, provided mean recovery values between 79 and 100% for spiked water samples, it could not be applied to the extraction of these pesticides from wine samples due to high interference from the sample matrix. However, the use of a SPME procedure using polydimethylsiloxane/divynilbenzene (PDMS/DVB) fibers allowed the selective extraction of four of the five pesticides which could be perfectly determined. The final combination of the off-line SPME and on-line REPSM preconcentration strategies allowed obtaining LODs between 17.6 and 32.3 microg/L.  相似文献   

3.
In this work, a new multiresidue analytical method based on MEKC with UV detection combined with SPE as off-line preconcentration strategy, and reversed-electrode polarity stacking mode (REPSM) as on-line stacking procedure, has been developed for the monitoring of 12 pesticides (carbendazim, pirimicarb, metalaxyl, pyrimethanil, procymidone, nuarimol, azoxystrobin, tebufenozide, fenarimol, benalaxyl, penconazole, and tetradifon) that are currently being used in the Canary Islands (Spain). The optimized MEKC buffer, consisting of 100 mM sodium tetraborate and 30 mM SDS at pH 8.5 with 6% v/v 1-propanol, provided baseline resolution of the 12 pesticides in less than 20 min. The developed method was applied to the analysis of mineral, stagnant, and tap water samples. The proposed SPE-REPSM-MEKC-UV method showed high extraction efficiencies with detection limits (LODs) at the low ng/L level providing LOD values down to 64 ng/L for these real samples.  相似文献   

4.
高效液相色谱-串联质谱法检测红葡萄酒中功效成分   总被引:1,自引:0,他引:1  
冯峰  程甲  粟有志  张峰  赵丹 《色谱》2017,35(2):178-184
建立了高效液相色谱-串联质谱法快速测定葡萄酒中白藜芦醇、黄酮类、多酚类功效成分的分析方法。葡萄酒样品直接稀释后进样,用C18柱进行分离,以乙腈-0.1%(体积分数)甲酸水溶液为流动相进行梯度洗脱,通过多反应监测(MRM)模式进行检测。13种功效成分在各自线性范围内呈良好的线性关系,相关系数均大于0.99。除表没食子儿茶素、没食子儿茶素、儿茶素没食子酸酯、花旗松素的检出限为1.0、1.0、3.0、3.0μg/L外,其他9种化合物的检出限均小于1.0μg/L。回收率为80.9%~112.3%,相对标准偏差小于10%。该方法快速、准确、灵敏度高,适用于葡萄酒中功效成分的快速分析。对实际样品的检测表明,所测葡萄酒样品中均含有儿茶素、表儿茶素、表没食子儿茶素、没食子儿茶素、表儿茶素没食子酸酯/儿茶素没食子酸酯、白藜芦醇、大豆黄素等功效成分,不同品种葡萄酒中这些功效成分含量差异显著。  相似文献   

5.
The applicability of an ionic liquid‐based cationic surfactant 1‐dodecyl‐3‐methyl‐imidazolium tetrafluoroborate (C12MImBF4) as pseudostationary phase in MEKC has been evaluated for the analysis of 11 carbamate pesticides (promecarb, carbofuran, metolcarb, fenobucarb, aldicarb, propoxur, asulam, benomyl, carbendazim, ethiofencarb, isoprocarb) in juice samples. Under optimum conditions (separation buffer, 35 mM NaHCO3 and 20 mM C12MImBF4, pH 9.0; capillary temperature 25°C; voltage –22 kV) the analysis was carried out in less than 12 min, using hydrodynamic injection (50 mbar for 7.5 s) and detection at 200 nm. For the extraction of these CRBs from juice samples, a dispersive liquid–liquid microextraction (DLLME) procedure has been proposed, by optimization of variables affecting the efficiency of the extraction. Following this treatment, sample throughput was approximately 12 samples per hour, obtaining a preconcentration factor of 20. Matrix‐matched calibration curves were established using tomato juice as representative matrix (from 5 to 250 μg/L for CBZ, BY, PX, CF, FEN, ETH, ISP, and 25–250 μg/L for ASL, ALD, PRC, MTL), obtaining quantification limits ranging from 1 to 18 μg/L and recoveries from 70 to 96%, with RSDs lower than 9%.  相似文献   

6.
The analysis of a group of seven pesticides (i.e. six fungicides: pyrimethanil, procymidone, nuarimol, fenarimol, benalaxyl and penconazole and one insecticide: pirimicarb) in tomato samples by micellar electrokinetic chromatography is investigated. For this purpose, reversed electrode polarity stacking mode and solid-phase microextraction (SPME) have been used as on-line and off-line preconcentration procedures, respectively. Tomato samples were first homogenized and extracted with acetone. After suitable evaporation and reconstitution of the extract in water, a SPME procedure using poly(dimethylsiloxane)/divinylbenzene fibers was used. Due to the strong influence of the sample matrix in the extraction, a matrix matched calibration of spiked tomato samples was developed. The method was found to be linear between 0.5 and 2.5 mg/kg. Limits of detection achieved are below the maximum residue limits established by the European Union and Spain legislation as well as by the Codex Alimentarius (except for penconazole). The potential of the method was demonstrated by analyzing 12 tomato samples (of ecological and non-ecological production) taken from regional cultivars. No residues of the selected pesticides were detected in any of the samples.  相似文献   

7.
The current work presents analytical procedures for simultaneous determination of tarabine PFS and adriblastina by micellar electrokinetic chromatography (MEKC) and liquid chromatography (LC). For MEKC analysis, separations and identifications were accomplished using uncoated fused-silica capillary with hydrodynamic injections in the presence of 50mM borate/phophate pH 8.7 and 100mM SDS. The migration times of tarabine PFS and adriblastina were found to be 2.70 and 6.40min, respectively. Calibration curves were established for 10-300ng/mL (r=0.998) tarabine PFS and for 8-120microg/mL (r=0.999) adriblastina. For LC analysis, separations were performed on teicoplanin stationary phase with reversed mobile phase containing methanol:buffer pH 4.05 (20:80%, v/v) at 285nm. The retention times of tarabine PFS and adriblastina were 5.18 and 7.20min, respectively. Calibration curves were established for 3-90microg/mL (r=0.998) tarabine PFS and for 10-120microg/mL (r=0.999) adriblastina. Both MEKC and LC methods were applied for the simultaneous determination of analytes in urine samples.  相似文献   

8.
The likely presence in wine of residues of the active ingredient and its degradation products, besides the byproducts and excipients of the commercial formulation, has been investigated for four pesticides. Formulations containing chlorpyriphos-methyl, methiocarb, dicofol, and cyproconazol were added to must, which was subjected to a usual vinification. The wines elaborated from must spiked with the formulation of chlorpyriphos-methyl contained two pyridinol compounds in addition to excipients such as alkylbenzenes, naphthalene, and methylnaphthalenes. Methiocarb was hydrolyzed to yield the corresponding phenol, and various unidentified compounds related to cyproconazol were observed in wine. The residues of the dicofol-containing formulation resulted to be dechlorination products; impurities from its commercial formulation were also detected in must and wine extracts. White wines contained higher amounts of residues than red wines. The residues were detected after an SPE followed by GC/EIMS in the scan mode. The concentrations of the active ingredients were determined by a matrix-matched calibration to avoid quantitative errors arising from the matrix.  相似文献   

9.
Detection of pesticide residues in food samples is important for safeguarding food quality and safety. Conventional approaches for detection of pesticides in food samples typically involve labour‐intensive and time‐consuming sample pretreatment and chromatographic separation. In this study, solid phase micro‐extraction fibres were used to rapidly extract and enrich pesticides in honey, a popular agricultural product with complex matrix, and then directly coupled with electrospray ionization mass spectrometry for qualitative and quantitative analysis. Three pesticides, ie, atrazine, benalaxyl, and pirimicarb, were investigated using the technique and their analytical performances were evaluated. The limits of detection and limits of quantitation of all the three pesticides could fulfil the cut‐off values of the international standard. Linear calibration curves were constructed with good R2 coefficients, and the accuracy and precision were in acceptable ranges for all the pesticides. The analysis time is much reduced, with only minimum sample preparation and no chromatographic separation involved. The technique is simple and easy to set up, and can be extended for analysis of other analytes and sample systems.  相似文献   

10.
A RP-HPLC method with photodiode array detection (DAD) was developed to separate, identify and quantify simultaneously the most representative phenolic compounds present in Madeira and Canary Islands wines. The optimized chromatographic method was carefully validated in terms of linearity, precision, accuracy and sensitivity. A high repeatability and a good stability of phenolics retention times (< 3%) were obtained, as well as relative peak area. Also high recoveries were achieved, over 80.3%. Polyphenols calibration curves showed a good linearity (r(2) >0.994) within test ranges. Detection limits ranged between 0.03 and 11.5 microg/mL for the different polyphenols. A good repeatability was obtained, with intra-day variations less than 7.9%. The described method was successfully applied to quantify several polyphenols in 26 samples of different kinds of wine (red, rosé and white wines) from Madeira and Canary Islands. Gallic acid was by far the most predominant acid. It represents more than 65% of all phenolics, followed by p-coumaric and caffeic acids. The major flavonoid found in Madeira wines was trans-resveratrol. In some wines, (-)-epicatechin was also found in highest amount. Canary wines were shown to be rich in gallic, caffeic and p-coumaric acids and quercetin.  相似文献   

11.
The determination of pesticides in food products is an essential issue to guarantee food safety and minimise health risks of consumers. A protocol based on membrane-assisted solvent extraction and liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) that allows the determination of 18 pesticides in red wine at minimum labour effort for sample preparation was developed and validated. Ten millilitres of wine were extracted using 100 μL of toluene filled in a non-porous polyethylene membrane bag which is immersed in the wine sample. After 150 min extraction under stirring, an aliquot of the extraction solution is analysed using HPLC-MS/MS. The limits of quantification ranged from 3 ng/L for Pirimicarb to 1.33 μg/L for Imidacloprid. Quantification by matrix-matched calibration provided relative standard deviations ≤16 % for most of the target pesticides. The linearity of calibration was given over three to four orders of magnitude, which enables the reliable measurement of a broad range of pesticide concentrations, and for each target pesticide, the sensitivity of the protocol meets the maximum residue levels set by legislations at least for wine grapes. Good agreement of results was found when the new method was compared with a standard liquid-liquid extraction protocol. In five wine samples analysed, Carbendazim and Metalaxyl were determined at micrograms per litre concentrations, even in some of the organic wines. Tebuconazol and Cyprodinitril were determined at lower abundance and concentration, followed by Spiroxamin and Diuron.  相似文献   

12.
Quantitative high-performance liquid chromatographic (HPLC) and micellar electrokinetic chromatographic (MEKC) methods have been developed for the determination of four structurally related potential manufacturing impurities, including morphine, of the opiate derivative pholcodine. Pholcodine and the four impurities were separated by MEKC in less than 14 min using a 70 cm x 75 microm I.D. uncoated fused-silica capillary (25 kV at 30 degrees C) and a running buffer consisting of 10% acetonitrile (v/v) in 20 mM borate-phosphate buffer pH 8.0 containing 40 mM sodium dodecyl sulphate (SDS). The MEKC method was compared to a HPLC method using a 5 microm Luna phenyl-hexyl column (150 x 4.6 mm I.D.) eluted with a mobile phase consisting of a mixture of 10% (v/v) acetonitrile, 7% (v/v) tetrahydrofuran in 20 mM phosphate buffer pH 8.0. Both methods were fully validated and a comparison was made regarding selectivity, linearity, precision, robustness and limits of detection and quantitation. The presence of the impurities in different samples of pholcodine drug substance was investigated using both methods.  相似文献   

13.
Amino acids were derivatised with 4-fluoro-7-nitrobenzo-2,1,3-oxadiazol (NBD-F), separated by micellar electrokinetic chromatography (MEKC), and detected by argon-ion (488 nm) laser-induced fluorescence. The optimised MEKC background electrolyte conditions were: 40 mM sodium cholate, 5 mM beta-cyclodextrin in 20 mM aqueous borate buffer, pH 9.1, with 7% v/v acetonitrile. Using these conditions, 19 amino acids were separated within 17 min. The limits of detection were in the range of 7.6-42.2 pmol/mL and limits of quantitation from 0.05-0.14 nmol/mL. The method was systematically validated for injection volume error, migration time variation, calibration linearity, accuracy, precision, and recovery. Nanolitre volume samples of phloem sap of individual sieve element cells from the plant Arabidopsis thaliana and honeydew from the aphid Myzus persicae were directly analysed with this method. Quantitative amino acid concentrations in these two biological matrices were profiled for the first time. This method is particularly important because it allows the complete profile of the amino acids obtained from individual phloem elements, allowing cell to cell and plant to plant variation to be quantified, which to date has not been possible with Arabidopsis thaliana.  相似文献   

14.
An analytical method devoted to organotin compounds (OTC) determination in brandy and wine was developed. It is based on solid-phase microextraction (SPME) of ethylated organotins. The following operating factors were examined: SPME mode/nature of fibre coating, sample volume/dilution, and sampling time. The optimisation work led to dilute the sample in an aqueous buffer (1/11, v/v ratio) in order to satisfactorily decrease the matrix effects due to competitive sorption of non-OTC species onto/into fibre coating. The optimised operating conditions consist of polydimethylsiloxane (PDMS) coated fibre used in headspace mode for 30 min. In wines, the limits of detection (LOD) and quantification (LOQ) ranged from 1 to 40 and 3 to 80 ng(Sn)L(-1) respectively, according to the species. The analytical validation was made by evaluating the accuracy of OTC determination in spiked samples with various concentrations over the whole calibration range, i.e. from LOQ to 1000 ng(Sn)L(-1). Recovery was around 80-110% and precision (relative standard deviation, RSD) was between 12% and 25%. Despite the presence of two chromatographic peaks corresponding to sulphur compounds during brandy analysis, the selectivity of the method is adequate. The analysis confirmed the analytical performances and applicability of the method to wine and brandy samples. The obtained results emphasise the contamination of brandy and wine by organotins, the storage in plastic container seeming to be confirmed as the main OTC source.  相似文献   

15.
In this work, NACE with UV detection is combined with SPE using multi-walled carbon nanotubes (MWCNT) as stationary phase to determine a group of seven pesticides (pirimicarb, pyrifenox, penconazol, carbendazim, cyromazine, pyrimethanil and cyprodinil) in mineral water samples using ametryn as internal standard. The optimized BGE, consisting of a mixture of MeOH and ACN (1:2 v/v) with 90 mM SDS and 20.5 mM HClO(4), was satisfactory to get a good resolution of the seven compounds in less than 13 min. On-line preconcentration was carried out by electrokinetic injection of the sample dissolved in 78:22 v/v MeOH/ACN, 1.11 mM HClO(4). Repeatability was studied for the same day (n=4), for nine different days (n=36) and for four different capillaries. RSD values were appropriate in all cases, i.e. in the range 4.3-9.4% between different capillaries. MWCNT of 10-15 nm od, 2-6 nm id and 0.1-10 mum length were used as SPE materials for the preconcentration of these pesticides from water samples. SPE parameters influencing the enrichment were optimized and the most favorable conditions were as follows: the amount of stationary phase, eluent, sample pH and sample volume were 40 mg MWCNT, 10 mL ACN and 10 mL dichloromethane containing 5% v/v formic acid, pH 8.0, and 750 mL, respectively. Mean recovery values ranged between 53 and 94% for Milli-Q water and between 47 and 93% for mineral waters (RSD values were in the range 2-16%). The method allowed the determination of these pesticides at concentrations below the maximum residue limits established by the European Union legislation (LOD in the range 27-58 ng/L). When the cost, amount and type of the carbon nanotubes used in this work are compared with those carbon nanotubes previously used in the literature it is clear that the proposed materials can be used as economical stationary phases, even cheaper than conventional SPE cartridges.  相似文献   

16.
In this paper, we propose a comparative study to check the matrix effect on the extraction of three chlorophenols, 2,4,6-trichlorophenol (TCP), 2,3,4,6-tetrachlorophenol and pentachlorophenol, direct precursors of 2,4,6-trichloroanisole, in synthetic and commercial wines (white and red wines). A rapid, simple and sensitive methodology based on solid-phase microextraction (SPME) and GC with electron capture detection (GC-ECD) and mass spectrometric detection (GC-MS) was developed and the variables affecting the extraction process (temperature, time and salt content) were examined employing a factorial design at two levels. Since GC-ECD does not allow the clear identification of target analytes in white wine, owing to overlapped interferences, GC-MS/MS was used for subsequent examinations. Calibration curves were constructed in synthetic, white and red wine. Significant differences between the slopes of synthetic and red wine, with the exception of TCP, were observed. Analytical parameters were evaluated and satisfactory results were obtained, showing the usefulness of the headspace SPME (HS-SPME) method for determining chlorophenolic compounds in wines.  相似文献   

17.
A rapid pioneering method has been developed to simultaneously determine residues of three pesticides (thiamethoxam, clothianidin, and metazachlor) in soil by ultrahigh performance liquid chromatography coupled to a mass spectrometry detector (quadrupole time‐of‐flight). An efficient extraction procedure (90–105% average analyte recoveries) has also been proposed, involving solid–liquid extraction by a mixture of water and methanol (60:40, v/v), centrifugation, and concentration. A chromatographic analysis of the compounds was achieved in 5.5 min by means of a core–shell technology based column (Kinetex® EVO C18, 50 × 2.1 mm, 1.7 μm, 100 Å). The mobile phase (0.3 mL/min, gradient elution mode) consisted of 0.1% v/v formic acid in water and 0.1% v/v formic acid in acetonitrile. The method was fully validated in terms of selectivity, detection and quantification limits, matrix effect, linearity, trueness, and precision. Low limits of detection and quantification were obtained, ranging from 0.2 to 3.0 μg/kg, which are similar to those published in previous studies, while the absence of a significant matrix effect allowed quantification of the pesticides with standard calibration curves. The proposed method was applied for an analysis of pesticides in several soil samples from experimental fields dedicated to oilseed rape cultivars.  相似文献   

18.
In this study, we described a high‐sensitive on‐line preconcentration method for cypromazine (CYP) and melamine (MEL) analysis using cation‐selective exhaustive injection (CSEI) combined with sweeping‐MEKC. The optimum conditions of on‐line concentration and separation were discussed. The BGE contained 100 mM SDS, 50 mM phosphoric acid (pH=2.0) and 15% acetonitrile (v/v). The sample was injected at 10 kV for 600 s, separated at ?20 kV, and detected at 210 nm. The sensitivity enhancements were 6222 for CYP and 9179 for MEL. The linear dynamic ranges were 0.4?25 ng/mL for CYP (r=0.9995) and 0.2?12 ng/mL for MEL (r=0.9991). The LODs (signal‐to‐noise ratio, 3) were 43.7 and 23.4 pg/mL for CYP and MEL, respectively. The proposed method was applied to analyze CYP and MEL in dairy products pretreated using off‐line SPE to minimize the influence of the matrix. The recoveries of CYP and MEL were satisfactory (ca. 74–83%). The experimental results suggest that the CSEI‐sweeping‐MEKC method is feasible for the application to simultaneously detect trace levels of CYP and its metabolite MEL in real milk samples.  相似文献   

19.
Analytical methodology was developed and validated for the determination of spiroxamine residues in grapes, must, and wine by gas chromatography/ion trap-mass spectrometry (GC/IT-MS). Two extraction procedures were used: the first involved grapes, must, and wine extraction with alkaline cyclohexane-dichloromethane (9 + 1, v/v) solution, and the second grape extraction with acetone, dichloromethane, and petroleum ether. In both procedures, the extract was centrifuged, evaporated to dryness, and reconstituted in cyclohexane or 2,2,4-trimethylpentane-toluene (9 + 1, v/v), respectively. Spiroxamine diastereomers A and B were determined by GC/IT-MS, and a matrix effect was observed in the case of grapes but not in must and wine. Recovery of spiroxamine from fortified samples at 0.02 to 5.0 mg/kg ranged from 78-102% for grapes and must, with relative standard deviation (RSD) <13%; for red and white wines, recoveries ranged from 90 to 101% with RSD <9%. The limit of quantification was 0.02 mg/kg for grapes, must, and wine or 0.10 mg/kg for grapes, depending on the extraction procedure used.  相似文献   

20.
《Analytical letters》2012,45(16):3080-3094
Abstract

An accurate method based on the use of reversed‐phase high performance liquid chromatography coupled with diode‐array detection was devised for the determination of five synthetic food colorants added to alcoholic beverages with natural colors. A C18 stationary phase was used and the mobile phase contained methanol and 40 mM ammonium acetate buffer solution. The synthetic food colorants were detected at their corresponding individual characteristic maxima of absorbance wavelength. Successful separation was achieved within 11 min for all the analytes using an optimized gradient elution, column temperature, buffer concentration and flow rate. Accurate sample quantification was feasible using matrix‐matched calibration curves. The method was successfully validated by determination of linearity ranges, the limits of quantification and detection, precision and recovery for all colorants tested. The proposed and validated method was used to analyze some alcoholic beverage samples, consisting of eight red wines, six coolers, four aromatized spirits, five bitters, three cocktails and four liquors from different Chinese manufacturers. The results showed the bitters and red wines did not have synthetic colorants, but colorants were found in all the samples of other kinds of alcoholic beverages. No analyzed sample exceeded the limit established by Chinese legislation.  相似文献   

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