Determination of metoserpate,buquinolate, and diclofenac in pork,eggs, and milk using liquid chromatography–tandem mass spectrometry

In this work, a method was developed for the simultaneous determination of residual metoserpate, buquinolate and diclofenac in pork, milk, and eggs. Samples were extracted with 0.1% formic acid in acetonitrile, defatted with n‐hexane, and filtered prior to analysis using liquid chromatography–tandem mass spectrometry. The analytes were separated on a C₁₈ column using 0.1% acetic acid and methanol as the mobile phase. The matrix‐matched calibration curves showed good linearity over a concentration range of 5–50 ng/g with coefficients of determination (R²) ≥0.991. The intra‐ and inter‐day accuracies (expressed as recovery percentage values) calculated using three spiking levels (5, 10, and 20 μg/kg) were 80–108.65 and 74.06–107.15%, respectively, and the precisions (expressed as relative standard deviation) were 2.86–13.67 and 0.05–11.74%, respectively, for the tested drugs determined in various matrices. The limits of quantification (1 and 2 μg/kg) were below the uniform residual level (0.01 mg/kg) set for compounds that have no specific maximum residue limit (MRL). The developed method was tested using market samples and none of the target analytes was detected in any of the samples. The validated method proved to be practicable for detection of the tested analytes in pork, milk, and eggs.     

Ultra‐fast liquid chromatography with tandem mass spectrometry determination of ochratoxin A in traditional Chinese medicines based on vortex‐assisted solid–liquid microextraction and aptamer‐affinity column clean‐up

A rapid, selective, and sensitive ultra‐fast liquid chromatography with tandem mass spectrometry method was developed for the determination of ochratoxin A in traditional Chinese medicines based on vortex‐assisted solid–liquid microextraction and aptamer‐affinity column clean‐up. Through optimizing the sample pretreatment procedures and chromatographic conditions, good linearity (r² ≥ 0.9993), low limit of detection (0.5–0.8 μg/kg), and satisfactory recovery (83.54–94.44%) expressed the good reliability and applicability of the established method in various traditional Chinese medicines. Moreover, the aptamer‐affinity column, prepared in‐house, showed an excellent feasibility owing to its specific identification of ochratoxin A in various kinds of selected traditional Chinese medicines. The maximum adsorption amount and applicability value were 188.96 ± 10.56 ng and 72.3%, respectively. The matrix effects were effectively eliminated, especially for m/z 404.2→358.0 of ochratoxin A. The application of the developed method for screening the natural contamination levels of ochratoxin A in 25 random traditional Chinese medicines on the market in China indicated that only eight samples were contaminated with low levels below the legal limit (5.0 μg/kg) set by the European Union. This study provided a preferred choice for the rapid and accurate monitoring of ochratoxin A in complex matrices.     

Liquid chromatography with tandem mass spectrometry method for the determination of nicotine and minor tobacco alkaloids in electronic cigarette refill liquids and second‐hand generated aerosol

A liquid chromatography with tandem mass spectrometry method for the simultaneous quantification of nicotine and seven minor tobacco alkaloids in both refill liquids for electronic cigarettes and their generated aerosol was developed and validated. The limit of detection and limit of quantification values were 0.3–20.0 and 1.0–31.8 ng/mL, respectively. Within‐laboratory reproducibility was 8.2–14.2% at limit of quantification values and 4.8–12.7% at other concentration levels. Interday recovery was 75.8–116.4%. The method was applied to evaluate the compliance of commercial liquids (n = 95) with their labels and to assess levels of minor alkaloids. Levels of nicotine and its corresponding compounds were also evaluated in generated aerosol. About 47% of samples showed differences above ±10 % of the stated nicotine concentration. About 78% of the “zero nicotine” liquids showed traces in the range of 1.3 ± 0.1–254.0 ± 14.6 μg/mL. Nicotine‐N ′‐oxides, myosmine, and anatabine were the most common minor alkaloids in liquids containing nicotine. Nicotine and N ′‐oxides were detected in all air samples when aerosol was generated from liquids containing nicotine. Nicotine average emissions from electronic cigarette (2.7 ± 0.9 μg/m³) were significantly lower (p < 0.01, t‐test) with respect to conventional cigarette (30.2 ± 1.5 μg/m³).     

Comparison of air‐agitated liquid–liquid microextraction and ultrasound‐assisted emulsification microextraction for polycyclic aromatic hydrocarbons determination in hookah water

In this work, two disperser‐free microextraction methods, namely, air‐agitated liquid–liquid microextraction and ultrasound‐assisted emulsification microextraction are compared for the determination of a number of polycyclic aromatic hydrocarbons in aqueous samples, followed by gas chromatography with flame ionization detection. The effects of various experimental parameters upon the extraction efficiencies of both methods are investigated. Under the optimal conditions, the enrichment factors and limits of detection were found to be in the ranges of 327–773 and 0.015–0.05 ng/mL for air‐agitated liquid–liquid microextraction and 406–670 and 0.015–0.05 ng/mL for ultrasound‐assisted emulsification microextraction, respectively. The linear dynamic ranges and extraction recoveries were obtained to be in the range of 0.05–120 ng/mL (R² ≥ 0.995) and 33–77% for air‐agitated liquid–liquid microextraction and 0.05–110 ng/mL (R² ≥ 0.994) and 41–67% for ultrasound‐assisted emulsification microextraction, respectively. To investigate this common view among some people that smoking hookah is healthy due to the passage of smoke through the hookah water, samples of both the hookah water and hookah smoke were analyzed.     

Development and validation of an analytical method for determination of endocrine disruptor, 2,4-D, in paddy field water

The acidic herbicides are an important class of chemical compounds that are used to control a variety of weeds that threaten many crops. Owing to their low microbial activity levels, the acidic herbicides exhibit a residual activity remaining for periods of up to several months in soils and water. The principal objective of this study was to develop an analytical method based on liquid–liquid and solid‐phase extraction followed by HPLC, for the determination of 2,4‐D in paddy field water. The residues were verified via tandem mass spectrometry (MS/MS) in negative‐ion electrospray ionization (ESI) mode. Linearity was good over a concentration range of 1–100 µg/L with a correlation coefficient (r²) of 0.999. The mean recovery rates of triplicate results ranged from 85.2 to 90.85%. The limits of detection and quantitation were 0.4 and 1.0 µg/L, respectively. The method proposed herein was applied to field samples acquired from Hampyung and Sunchang counties, Republic of Korea. The analyte was detected at a concentration range of 6.8–12.8 and 3.55–24.0 µg/L, respectively. Copyright © 2010 John Wiley & Sons, Ltd.     

Preparation of dummy‐imprinted polymers by Pickering emulsion polymerization for the selective determination of seven bisphenols from sediment samples

The dummy molecularly imprinted polymers were prepared by Pickering emulsion polymerization. 4,4′‐(1‐Phenylethylidene) bisphenol was selected as the dummy template to avoid the leakage of the target bisphenols. The microsphere particles were characterized by scanning electron microscopy and nitrogen adsorption–desorption measurements, demonstrating that the regular‐shaped and medium‐sized particles (40–70 μm) were obtained with a specific surface area of 355.759 m²/g and a total pore volume of 0.561 cm³/g. The molecular imprinting properties of the particles were evaluated by static adsorption and chromatographic evaluation experiments. The association constant and maximum adsorption amount of bisphenol A were 0.115 mmol/L and 3.327 μmol/g using Scatchard analysis. The microsphere particles were then used as a solid‐phase extraction sorbent for selective extraction of seven bisphenols. The method of dummy molecularly imprinted solid‐phase extraction coupled with high‐performance liquid chromatography and diode array detection was successfully established for the extraction and determination of seven bisphenols from environmental sediment samples with method detection limits of 0.6–1.1 ng/g. Good recoveries (75.5–105.2%) for sediment samples at two spiking levels (500 and 250 ng/g) and reproducibility (RSDs < 7.7%, n = 3) were obtained.     

Determination of five sulfonylurea herbicides in environmental waters and soil by ultra high performance liquid chromatography with tandem mass spectrometry after extraction using graphene

A fast and novel analytical method was developed for the determination of trace levels of sulfonylurea herbicides in water and soil samples. Graphene was used as a sorbent for extraction, and ultra high performance liquid chromatography with tandem mass spectrometry was used for quantification. Five sulfonylurea herbicides were preconcentrated from water samples using a graphene‐loaded packed cartridge, while extraction from soil samples was performed in a single step using graphene‐supported matrix solid‐phase dispersion. Under the optimized conditions, the calibration plots were linear in the range between 5 and 1000 ng/L for water samples, and between 1 and 200 ng/g for soil samples. All correlation coefficients (R) were >0.99. The limits of detection for water and soil samples were 0.28–0.53 ng/L and 0.08–0.26 ng/g, respectively. This method was successfully applied to the analysis of spiked samples of environmental water and soil, with recoveries ranging from 84.2–109.3 and 86.12–103.2%, respectively, all with relative standard deviations of <10%.     

Determination of Organophosphorus P sticides in Water, Vegetables and Grain by Automated SPE and MEKC

A sensitive method for the multi-residue analysis of organophosphorus pesticides in environmental samples has been developed. It involves an automated solid phase extraction procedure using a Gilson ASPEC XLi and capillary electrophoresis analysis with UV detection. Acephate, methamidophos, dichlorvos, dicrotophos and malathion could be separated by micellar electrokinetic capillary chromatography using an electrophoretic electrolyte containing 20 mM phosphate buffer (pH 7.5) and 75 mM sodium dodecyl sulphate. A linear relationship between concentration and peak area was obtained within the range 0.2–450 g mL^?1 with correlation coefficients greater than 0.996 and detection limits between 7 and 150 ng mL^?1. Intra- and inter-day precision values of about 0.8–2.3% RSD (n=11) and 0.9–3.0% RSD (n=15), respectively were obtained. When the preconcentration step was used, an enrichment factor of 250 was easily achieved in the analysis of water samples, making it possible to determinate pesticide residues at concentration levels as low as 0.04 ng mL^?1. In analyses of vegetables and grains, the sensitivity levels were about 0.03 μg^?1.     

A novel fast method for aqueous derivatization of THC,OH‐THC and THC‐COOH in human whole blood and urine samples for routine forensic analyses

A novel aqueous in situ derivatization procedure with propyl chloroformate (PCF) for the simultaneous, quantitative analysis of Δ⁹‐tetrahydrocannabinol (THC), 11‐hydroxy‐Δ⁹‐tetrahydrocannabinol (OH‐THC) and 11‐nor‐Δ⁹‐tetrahydrocannabinol‐carboxylic acid (THC‐COOH) in human blood and urine is proposed. Unlike current methods based on the silylating agent [N,O‐bis(trimethylsilyl)trifluoroacetamide] added in an anhydrous environment, this new proposed method allows the addition of the derivatizing agent (propyl chloroformate, PCF) directly to the deproteinized blood and recovery of the derivatives by liquid–liquid extraction. This novel method can be also used for hydrolyzed urine samples. It is faster than the traditional method involving a derivatization with trimethyloxonium tetrafluoroborate. The analytes are separated, detected and quantified by gas chromatography–mass spectrometry in selected ion monitoring mode (SIM). The method was validated in terms of selectivity, capacity of identification, limits of detection (LOD) and quantification (LOQ), carryover, linearity, intra‐assay precision, inter‐assay precision and accuracy. The LOD and LOQ in hydrolyzed urine were 0.5 and 1.3 ng/mL for THC and 1.2 and 2.6 ng/mL for THC‐COOH, respectively. In blood, the LOD and LOQ were 0.2 and 0.5 ng/mL for THC, 0.2 and 0.6 ng/mL for OH‐THC, and 0.9 and 2.4 ng/mL for THC‐COOH, respectively. This method was applied to 35 urine samples and 50 blood samples resulting to be equivalent to the previously used ones with the advantage of a simpler method and faster sample processing time. We believe that this method will be a more convenient option for the routine analysis of cannabinoids in toxicological and forensic laboratories.     

Facile LC‐UV methods for simultaneous monitoring of ciprofloxacin and rosuvastatin in API,formulations and human serum

An efficient, selective and cost‐effective liquid chromatographic assay was developed and validated for the simultaneous quantification of ciprofloxacin and rosuvastatin in Active Pharmaceutical Ingredients (API), pharmaceutical formulations and in human serum. The chromatographic system consisted of mobile phase methanol–water, 90:10 v/v at pH 3.0 adjusted with o‐phosphoric acid, pumped at 1.0 mL/min through a prepacked Purospher Star C18 (5 µm, 25 × 0.46 cm) column and effluent was monitored at the isosbestic point (255 nm) as well as at the λ_max of individual drugs (243 and 271 nm). The method was validated over a linear concentration range of 0.25–15 µg/mL for ciprofloxacin and 0.33–20 µg/mL for rosuvastatin (r² ≥ 0.999). The ranges of reliable response (limits of detection and quantitation) for ciprofloxacin were 3–15 and 9–45 ng/mL and 17–29 and 52–88 ng/mL, respectively, for rosuvastatin in all API, pharmaceutical formulations and human serum. Analytical recovery from human serum was >98% and relative standard deviation (RSD) was <2. The accuracies were 97.13–102.55 and 97.41–101.31% and precisions in RSD were 0.04–1.90 and 0.02–1.23% for ciprofloxacin and rosuvastatin, respectively. No matrix interferences, ion suppression/enhancement and carry‐over were detected. The total assay run time was less than 5 min. In another study, for optimum performance the detector was programmed for multiwavelength scanning at the absorption maxima of each component. Consequently, the linearity range was improved and limit of detection and quantitation values were down to 1–4 and 4–12 ng/mL for ciprofloxacin and 3–5 and 9–15 ng/mL for rosuvastatin, respectively. The validation parameters fitted ICH guidelines through the isosbestic and individual λ_max approach. The small sample volume and simplicity of preparation make this method suitable for use in human serum samples, pharmaceutical formulations, quality control, drug–drug interaction studies, clinical laboratories, drug research centers and forensic medical centers. Copyright © 2014 John Wiley & Sons, Ltd.     

Determination of trace triclosan in environmental water by microporous bamboo‐activated charcoal solid‐phase extraction combined with HPLC‐ESI‐MS

A sensitive and efficient analytical method for triclosan (TCS) determination in water, which involves enrichment with bamboo‐activated charcoal and detection with HPLC‐ESI‐MS, was developed. The influence of several operational parameters, including the eluant and its volume, the flow rate, the volume andacidity of the sample, and the amount of bamboo‐activated charcoal, were investigated and optimized. Under the optimum conditions, linearity of the method was observed in the range of 0.02–20 μg/L, with correlation coefficients (r²) >0.9990. The limit of detection was 0.002 μg/L based on the ratio of chromatographic signal to baseline noise (S/N = 3). The spiked recoveries of TCS in real water samples were achieved in the range of 97.6–112.5%. The proposed method was applied to analyze TCS in real aqueous samples. All the surface water samples collected in Xiaoqing River had detectable levels of TCS with concentrations of 42–197 ng/L.     

Analysis of polybrominated diphenyl ethers in sewage sludge by matrix solid‐phase dispersion and isotope dilution GC–MS

A method for the determination of 14 polybrominated diphenyl ethers (PBDEs) in sludge from wastewater treatment plants is presented. PBDEs were extracted by matrix solid‐phase dispersion assisted by sonication and determined by isotope dilution gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode, using labelled ¹³C‐PBDEs as internal standards. The limits of detection and quantification for the tri‐ to hepta‐BDEs were in the range of 0.05 to 0.5 ng/g dry weight and 0.15 to 1.8 ng/g dry weight, respectively, and 1.6 ng/g dry weight and 5.6 ng/g dry weight for deca‐BDE‐209. The proposed analytical method was applied to determine PBDE levels in sewage sludge samples collected from 19 water treatment plants located in the province of Madrid (Spain). In all of the examined samples, BDE‐100 and BDE‐154 were the main compounds found with a mean concentration of 3.9 and 2.0 ng/g, respectively. PBDEs were detected in all of the samples, and their total concentrations not considering BDE‐209 were between 3.9 and 23.0 ng/g dry weight. The dominant PBDE congener in sewage sludge was BDE‐209, which constituted 38.7 to 97.3% of the total, and showed concentration levels ranging from 8.1 to 717.2 ng/g dry weight.     

Liquid‐phase microextraction based on two immiscible organic solvents followed by gas chromatography with mass spectrometry as an efficient method for the preconcentration and determination of cocaine,ketamine, and lidocaine in human urine samples

A new type of liquid‐phase microextraction based on two immiscible organic solvents was optimized and validated for the quantification of lidocaine, ketamine, and cocaine in human urine samples. A hollow‐fiber based microextraction technique followed by gas chromatography coupled with mass spectrometry detection was used to reduce matrix interferences and improve limits of detection. The analytes were extracted from aqueous sample with pH 11.0, into a thin layer of organic solvent (n‐dodecane) sustained in the pores of a hollow fiber, and then into a second organic acceptor (acetonitrile) located inside the lumen of the hollow fiber. With the application of optimized values, good linearity was obtained in the range of 1–500 μg/L for lidocaine and ketamine and 2–500 μg/L for cocaine with the determination coefficient values (r²) >0.9943. The preconcentration factors and limits of detection (S/N > 3) were 250–350 and 0.01–0.05 μg/L, respectively. Intra and interassay precision values were <7.3 and 9.3%, respectively. The method was successfully applied for the determination and quantification of target analytes in human urine samples.     

Rapid determination of residual pesticides in tobacco by the quick,easy, cheap,effective, rugged,and safe sample pretreatment method coupled with LC–MS

A quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample pretreatment method coupled with LC–MS was developed for the determination of 11 pesticides in tobacco. Sample pretreatment parameters and instrumental parameters of LC–MS were investigated, and the optimal conditions were selected. Under the optimized conditions, the 11 pesticides were detected simultaneously with a good linear relationship (r² = 0.9993–0.9999) and high precisions (less than 5% of the RSD of peak areas). The LODs were in the range of 0.1–5.0 μg/L. Compared with SPE clean‐up, QuEChERS greatly simplified the sample pretreatment with simple solvent extraction system. After QuEChERS pretreatment, no serious matrix effects were observed. Used for the analysis of real samples, metalaxyl was found in cigarette and tobacco samples at 63.47 and 132.27 ng/g, respectively. The recoveries for 11 pesticides were in the range of 70.03–118.69%, and RSDs were less than 10%. The proposed method is simple, low cost, and has good reproducibility.     

Effect of background derivatization on the signal enhancement of pesticide residues extracted from edible oils

The effect of background derivatization on the signal enhancement of pesticide residues extracted from edible oil samples was studied by GC with negative chemical ionization MS. The analytes were extracted by a solvent extraction process, and the extract was subjected to rapid low‐temperature fat precipitation. The residual fatty acids were silylated by derivatization with N,O‐bis(trimethylsilyl)trifluoroacetamide. The chromatograms obtained from the derivatized samples showed higher signal intensity and lower detection levels when compared to the direct analysis without derivatization. The sensitivity levels of the method are either better or comparable to that of previously reported methodologies. The LODs of the analyzed organochlorine, organophosphorus, and synthetic pyrethroid residues in sunflower, rice bran, and ground oil samples were in the range of 0.02–0.5 ng/g, and the LOQs were in the range of 0.1–2 ng/g. The intraday and interday accuracies were in the range of 81–116% with RSDs less than 14%. The recoveries obtained were in the range of 53–89% with the RSD values less than 13% for all the studied pesticide residues.     

Primary secondary amine as a sorbent material in dispersive solid‐phase extraction clean‐up for the determination of indicator polychlorinated biphenyls in environmental water samples by gas chromatography with electron capture detection

A simple, rapid, and novel method has been developed and validated for determination of seven indicator polychlorinated biphenyls in water samples by gas chromatography with electron capture detection. 1 L of water samples containing 30 g of anhydrous sodium sulfate was first liquid–liquid extracted with an automated Jipad‐6XB vertical oscillator using n‐hexane/dichloromethane (1:1, v/v). The concentrated extract was cleaned up by dispersive solid‐phase extraction with 100 mg of primary secondary amine as sorbent material. The linearity of this method ranged from 1.25 to 100 μg/L, with regression coefficients ranging between 0.9994 and 0.9999. The limits of detection were in the ng/L level, ranging between 0.2 and 0.3 ng/L. The recoveries of seven spiked polychlorinated biphenyls with external calibration method at different concentration levels in tap water, lake water, and sea water were in the ranges of 85–112, 76–116, and 72–108%, respectively, and with relative standard deviations of 3.3–4.5, 3.4–5.6, and 3.1–4.8% (n =  5), respectively. The performance of the proposed method was compared with traditional liquid–liquid extraction and solid‐phase extraction clean‐up methods, and comparable efficiencies were obtained. It is concluded that this method can be successfully applied for the determination of polychlorinated biphenyls in different water samples.     

Solid‐phase extraction coupled with ultra high performance liquid chromatography and electrospray tandem mass spectrometry for the highly sensitive determination of five iodinated X‐ray contrast media in environmental water samples

A highly sensitive method based on solid‐phase extraction and ultra high performance liquid chromatography with electrospray tandem mass spectrometry has been developed for simultaneous determination of five iodinated X‐ray contrast media in environmental water samples. Various solid‐phase extraction cartridges have been evaluated and a combination of LiChrolute EN and ENVI‐Carb solid phase extraction cartridges was selected for sample enrichment. The method was comprehensively validated on ground water, tap water, surface water, drinking water, and waste water by the conventional procedures: linearity, method detection limits, accuracy and precision, matrix effects. Good linearity (R² > 0.999), low detection limits (0.4–8.1 ng/L), satisfactory recoveries (55.1–109.5%) and precision (0.8–10.0% for intra‐day precisions and 0.6–16.5% for inter‐day precisions) were obtained for all the target compounds. Iopamidol, iohexol, and diatrizoate in some matrices were affected by matrix effects, which were slightly eased by using the isotope‐labeled internal standard. The developed method was successfully applied for real samples collected in Shanghai, China, with detected concentrations up to 2200 ± 200 and 9000 ± 1000 ng/L for iohexol and iopamidol, respectively.     

Phenyl‐functionalized silica‐coated magnetic nanoparticles for the extraction of chlorobenzenes,and their determination by GC‐electron capture detection

We have prepared a solid phase for the extraction of chlorobenzenes (CBs) by coating magnetic (Fe₃O₄) nanoparticles with silica via a sol‐gel process using a mixture of tetraethoxysilane and triethoxyphenylsilane. The nanoparticles were characterized by SEM, energy‐dispersive spectroscopy, and X‐ray diffractometry. The nanoparticles were used for the extraction of 1,4‐dichlorobenzene (1,4‐DCB), 1,2,3‐trichlorobenzene (1,2,3‐TCB), 1,2,4‐trichlorobenzene (1,2,4‐TCB), and 1,2,3,4‐tetrachlorobenzene (1,2,3,4‐TeCB) from water, followed by their determination by GC‐electron capture detection. Under optimal conditions, enrichment factors ranging from 220 to 360 were obtained. All determination coefficients (r²) are >0.99, and linear response is found in range 0.025–1.5 μg/L (at the lower end), and 6–120 μg/L (at the higher end). Detection limits are 6, 10, 11, and 500 ng/L for 1,2,3,4‐TeCB, 1,2,4‐TCB, 1,2,3‐TCB, and 1,4‐DCB, respectively. All RSDs are <6% (for n = 5). The method was successfully applied to the determination of CBs in environmental water samples.     

Development and validation of a multiresidue method for determination of 37 pesticides in soil using GC-NPD

In this study, a multiresidue analytical method for the detection of 37 pesticides in a soil matrix was developed and validated. The soil sample was fortified with a known quantity of pesticides at two different concentration levels (0.1 and 0.01 µg/g) and the analytes were extracted via a liquid–solid extraction method. The pesticides were separated on an HP5 capillary column and were analyzed with a gas chromatograph coupled to a nitrogen–phosphorous detector (GC‐NPD). Method validation was accomplished with good linearity (r² = 0.994–0.999) within a considerable range of concentrations. Satisfactory recoveries (70.5–110.4%) were obtained with 32 pesticides at both spiking concentration levels, whereas five pesticides—dimepiperate, buprofezin, prometryn, pirimicarb, and fludioxonil—were recovered at relatively low levels (43.6–61.8%). The applicability of the method was demonstrated by analyzing field samples collected from 24 different sites around Yeongsan and Sumjin rivers in the Republic of Korea. No residues of the selected pesticides were detected in any of the samples. The developed method could be employed as a simple and cost‐effective method for the routine detection and analysis of 37 pesticides in soil samples. Copyright © 2010 John Wiley & Sons, Ltd.     

Polyethylene glycol grafted flower‐like cupric nano oxide for the hollow‐fiber solid‐phase microextraction of hexaconazole,penconazole, and diniconazole in vegetable samples

A simple, rapid, highly efficient, and reliable sample preparation method has been developed for the extraction and analysis of triazole pesticides from cucumber, lettuce, bell pepper, cabbage, and tomato samples. This new sorbent in the hollow‐fiber solid‐phase microextraction method is based on the synthesis of polyethylene glycol‐polyethylene glycol grafted flower‐like cupric oxide nanoparticles using sol–gel technology. Afterward, the analytes were analyzed by high‐performance liquid chromatography with ultraviolet detection. The main parameters that affect microextraction efficiency were evaluated and optimized. This method has afforded good linearity ranges (0.5–50 000 ng/mL for hexaconazol, 0.012–50 000 ng/mL for penconazol, and 0.02–50 000 ng/mL for diniconazol), adequate precision (2.9–6.17%, n = 3), batch‐to‐batch reproducibility (4.33–8.12%), and low instrumental LODs between 0.003 and 0.097 ng/mL (n = 8). Recoveries and enrichment factors were 85.46–97.47 and 751–1312%, respectively.