Study on a Molecularly Imprinted Solid-Phase Extraction Coupled to Capillary Electrophoresis Method for the Determination of Trace Trichlorfon in Vegetables

How to determine the pesticide residues in vegetable is an urgent problem. In this study, we reported a new method of solid-phase extraction coupled to capillary electrophoresis (SPE–CE) based on a molecularly imprinted polymer (MIP) for determination of trace trichlorfon. The electrophoretic conditions and factors which affected the molecularly imprinted solid-phase extraction were optimized. Under optimal conditions, the linear ranges of the calibration graph were 0.1 μg/L to 10 mg/L. The limit of detection (LOD) and method quantitation limit (MQL) were 4.9 and 16.2 μg/kg, respectively. With a flow rate of 2.5 mL/min for 50 mL loading, an enrichment factor of 160 was obtained. The relative standard deviation (RSD) for five replicate extractions of 0.01 mg/L trichlorfon standard solution was 4.5 %. The blank cucumber, lettuce, and radish samples spiked with trichlorfon at three levels were extracted and determined by this presented method with recoveries ranging from 77.6 to 93.2 %. Moreover, this proposed methodology was successfully applied to the quantitative detection of the trichlorfon residues in the leek samples, and the results were in good agreement with that obtained by the gas chromatography method.     

Molecularly Imprinted Polymer as Sorbent for Solid-Phase Extraction Coupling to Gas Chromatography for the Simultaneous Determination of Trichlorfon and Monocrotophos Residues in Vegetables

In this study, a molecularly imprinted polymer (MIP) was prepared using the mixture of trichlorfon and monocrotophos as the mixed template. The imprinted polymer was characterized and exhibited good recognition ability and fast adsorption–desorption dynamic toward the trichlorfon and monocrotophos. Using this imprinted polymer as sorbent, a new method of molecularly imprinted solid-phase extraction coupled to gas chromatography for the simultaneous determination of two organophosphate pesticides residues was developed. Under optimal condition, the linear range was 0.005–10.0 mg/l. At a loading flow rate of 2.0 ml/min for loading 100 ml, the detection limits were 0.28 μg/l for trichlorfon and 0.090 μg/l for monocrotophos, the peak area precision (RSD) for five replicates was 4.23–4.50 %. The blank rape samples spiked with two organophosphate pesticides at 0.05 and 0.1 mg/l levels were determined by this method with recoveries ranging from 89.41 % to 95.12 %. Moreover, this method was successfully applied to the quantitative detection of the trichlorfon and monocrotophos residues in leek samples.     

Molecularly Imprinted Solid-Phase Extraction Coupled with High-Performance Liquid Chromatography for the Determination of Trace Trichlorfon and Monocrotophos Residues in Fruits

In this study, a novel molecularly imprinted polymer (MIL@MIP) that could selectively recognize the trichlorfon and monocrotophos was synthesized using metal-organic framework MIL-101 as support material. The prepared MIL@MIP was characterized by Fourier transform infrared, thermogravimetric analysis, scanning electron microscope, static adsorption, kinetic adsorption, and competitive adsorption analyses. Using this material as sorbent, a new method of molecularly imprinted solid-phase extraction coupled with high performance liquid chromatography for simultaneous determination of trichlorfon and monocrotophos was established. Under optimal conditions, the limit of detection (LOD) of this method for trichlorfon and monocrotophos detection was 0.011 and 0.015 mg/kg, respectively. The relative standard deviation (RSD) for five replicates of 0.05 mg/L trichlorfon and monocrotophos mixed solutions was within the range of 1.8 to 3.7 %. Apple and pear samples spiked with the two kinds of organophosphate pesticides were extracted and determined by using this method with good recoveries ranging from 86.5 to 91.7 %. Moreover, this method was successfully applied for the detection of the two organophosphate pesticides in strawberry samples.     

Application of Fast Gas Chromatography–Mass Spectrometry in Combination with the QuEChERS Method for the Determination of Pesticide Residues in Fruits and Vegetables

A fast gas chromatography–mass spectrometry method has been developed for multiresidue determination of up to 56 pesticides in fruits and vegetables in a chromatographic run time of <10 min, using a single quadrupole mass spectrometer operating in selected ion monitoring mode. The well-known acetate-buffering version of the QuEChERS method has been used for sample preparation. Programmable temperature vaporizer injection of 3 μL allowed reaching limits of detection between 0.15 and 15 μg/kg for most compounds in the sample matrices tested. The applicability of the method has been evaluated in apple, orange, carrot, and tomato. Recoveries at three fortification levels (0.01, 0.1 and 0.5 mg/kg) ranged from 70 to 120 % for most compounds, with relative standard deviations below 20 % in all cases. The developed method has been applied to fruit and vegetable samples from different Spanish provinces.     

Ultrasound-Assisted Extraction Followed by Solid-Phase Extraction Followed by Dispersive Liquid–Liquid Microextraction for the Sensitive Determination of Diazinon and Chlorpyrifos in Rice

Selectivity of solid-phase extraction (SPE) was combined with the concentration power of dispersive liquid–liquid microextraction (DLLME) to obtain a sensitive, low solvent consumption method for high-performance liquid chromatography determination of diazinon and chlorpyrifos in rice. In this method, rice samples were extracted by ultrasound-assisted extraction followed by SPE. Then, the SPE eluent was used as a disperser solvent in the next dispersive liquid-liquid microextraction step for further purification and enrichment of diazinon and chlorpyrifos. Under the optimal conditions, the linear range was from 5.0 to 250 μg kg^?1 for diazinon and from 2.5 to 250 μg kg^?1 for chlorpyrifos. Limits of detection of diazinon and chlorpyrifos were 1.5 and 0.7 μg kg^?1, respectively. Limits of quantitation of diazinon and chlorpyrifos were 5.5 and 3.0 μg kg^?1, respectively. The precisions and recoveries also were investigated by spiking 10 μg kg^?1 concentration in rice. The recoveries obtained were over 90 % with relative standard deviation (RSD%) below 9.0 %. The new approach was utilized to successfully detect trace amounts of diazinon and chlorpyrifos in different Iranian rice samples.     

Evaluation of Dispersive Liquid–Liquid Microextraction–HPLC–UV for Determination of Deoxynivalenol (DON) in Wheat Flour

A fast and simple method for the extraction of deoxynivalenol (DON) from wheat flour using dispersive liquid–liquid microextraction (DLLME) followed by high-performance liquid chromatography–UV detection has been developed and compared with immunoaffinity column cleanup (IAC) process. The influence of several important parameters on the extraction efficacy was studied. Under optimized conditions, a linear calibration curve was obtained in the range of 50–1,000 μg/L. Average recoveries of DON from spiked wheat samples at levels of 500 μg/kg for DLLME and IAC ranged from 72.9?±?1.6 and 85.5?±?3.1, respectively. A good correlation was found for spiked samples between DLLME and IAC methods. The limit of detection was 125 and 50 μg/kg for DLLME and IAC method, respectively. Advantages of DLLME method with respect to the IAC have been pointed out.     

Ochratoxin A in dried vine fruits from Chinese markets

A total of 56 dried vine fruits, including 31 sultanas and 25 currants, were selected from Chinese markets in 2012. All samples were analysed for Ochratoxin A (OTA) using solid-phase extraction and high-performance liquid chromatography (HPLC) with fluorescence detection. It turned out that 58.9% of the samples were positive and the OTA amount ranged from <0.07 to 12.83 μg/kg, with a mean level of 0.99 μg/kg. Only one sample exceeded the European Union (EU) maximum level of 10 μg/kg. Meanwhile, it was shown that OTA contamination increased among north-western, northern and southern China, which showed OTA means of 0.08, 0.99 and 2.01 μg/kg, respectively. Moreover, in samples of products sold in sealed plastic bags, i.e. consumer-size packages (n = 19, mean = 0.30 μg/kg) less OTA was detected when compared with sampled bulk packages (n = 37, mean = 1.67 μg/kg). In addition, sultanas (mean = 0.92 μg/kg) had less OTA contamination than currants (mean = 1.22 μg/kg).     

Investigation of Chlorpyrifos and Its Transformation Products in Fruits and Spices by Combining Electrochemistry and Liquid Chromatography Coupled to Tandem Mass Spectrometry

The identification of transformation products (TPs) of pesticides in food is a crucial task difficult to tackle, due to the lack of standards. In this work, we present a novel methodology to synthesize five main TP standards of the insecticide chlorpyrifos (CPF) and to investigate their occurrence in selected fruits and spices. TPs were electrochemically (EC) synthesized using a boron-doped diamond electrode (BDD) and identified by EC coupled online to mass spectrometry, LC-MS/MS, and high-resolution mass spectrometry. CPF and its TPs were analyzed in the food samples by LC-MS/MS on multiple reaction monitoring (MRM) after dispersive solid-phase extraction. A good recovery of 83–103% for CPF and 65–85% for TPs was obtained. Matrix effects, which cause signal suppression, ranged between 81 to 95% for all targeted analytes. The limit of detection and quantification for CPF were 1.6–1.9 and 4.9–5.7 μg/kg, respectively. Among investigated samples, CPF was determined in fresh lemon (104 μg/kg), fenugreek seed (40 μg/kg), and black pepper (31 μg/kg). CPF content in all samples was lower than the EU maximum residue level (MRL). The most frequently detected TPs were diethylthiophosphate and diethylphosphate. Other TPs, CPF oxon and trichloropyridinol, were also detected. Hence, EC is a versatile tool to synthesize TP standards which enables the determination of contaminants and residues in foodstuffs even if no commercial standards are available.     

Simultaneous Determination of Six Parabens in Foods by Matrix Liquid-Phase Dispersion Extraction Combined with High-Performance Liquid Chromatography

A novel microextraction method termed matrix liquid-phase dispersion extraction (MLPDE) was presented in this paper. This method was adopted for the extraction of preservatives including methylparaben, ethylparaben, propylparaben, butylparaben, isopropylparaben, and isobutylparaben from different solid food samples. The extracted analytes were subjected to high-performance liquid chromatography (HPLC) analysis immediately. In this method, the food sample (0.50 g) was added previously to a syringe and then rinsed with hot water (45 °C). Subsequently, 2 ml extraction solvent (methanol) was added into the syringe. After ultrasonic extraction, food sample was dispersed into the methanol phase and a cloudy suspension came into being. Under the pressure of the plunger, methanol carrying the target analytes passed through 0.45 μm membrane and 10.0 μl of the eluent was injected into HPLC system. The important parameters including temperature, pH and volume of water, extraction solvent and its volume, sodium chloride addition, sample weight, and ultrasonic time as well as matrix effect were investigated. Under the optimum conditions, recoveries of the studied preservatives ranged from 93.7 % to 107.9 %. The intra-day and inter-day precisions (relative standard deviations) were less than 5.16 % and 5.32 %, respectively. The linear ranges of the method were 0.947–400 mg/kg with the correlation coefficients of 0.9988 to 0.9999. The limits of detection were 0.285 to 1.122 mg/kg. MLPDE is a very simple, rapid, cheap, and efficient method for extraction of nonpolar organic compounds from solid food samples. The proposed method has been successfully applied to the separation and quantification of six parabens in different solid food samples.     

Simultaneous Determination of Organochlorine, Organophosphorus, and Pyrethroid Pesticides in Bee Pollens by Solid-Phase Extraction Cleanup Followed by Gas Chromatography Using Electron-Capture Detector

A method for routine determination of the residues of nine organochlorine pesticides (OCPs), ten organophosphorus pesticides (OPPs), and seven pyrethroid pesticides (PPs) in bee pollens was developed. Bee pollen samples were extracted by petroleum ether followed by solid-phase extraction cleaning and detected by gas chromatography–micro electron capture detection. Range of detection limits are 0.3–3.3 μg/kg for OCPs, 1.0–19.1 μg/kg for PPs and 1.1–19.7 μg/kg for OPPs. Recoveries of OCPs, OPPs, and PPs were in the range of 88.9–122.7 %, 86.8–123.1 %, and 90.8–118.7 %, respectively. The method was applied successfully to analyze real bee pollen samples. The results show a low level of contamination caused by pesticide residues indicating safe supply of bee pollen for consumers.     

A Rapid Screening Method for the Tremorgenic Indole-Diterpene Alkaloid Mycotoxin Paxilline in Beer

The tremorgenic paxilline (PAX), an indole-diterpene alkaloid mycotoxin, was recently detected as a natural contaminant of ergot of barley and rye. To check the possibility of a transfer of this mycotoxin into beer, a rapid and sensitive immunochemical method for the analysis of PAX in commercial bottled beer was developed. A straightforward sample preparation procedure could be established, including degassing, pH adjustment, optional filtering, and finally a 1:5 dilution with a methanolic phosphate-buffered saline solution. Analysis of PAX was performed by a competitive indirect enzyme immunoassay (EIA). The detection limit at a cut-off value of 80% B/B₀ of the EIA standard curve was evaluated by analysis of spiked beer. PAX at levels of 3 μg/L and 5 μg/L yielded 69% and 100% positive results, therefore the detection limit in beer was at 5 μg/L. Recoveries of PAX at levels of 5–20 μg/L were 88–97%, coefficients of variation were 17–22%. With these characteristics, the EIA was considered to be a suitable screening method for PAX in beer. A survey of bottled beer from the German market was conducted which included 38 samples of domestic and international brands, the latter containing various flavoring ingredients. All samples were clearly negative for PAX, which indicates that this toxin is not a relevant contaminant in beer.     

Evaluation of a Selective Approach for the Determination of 5-Nitroimidazoles in Aquaculture Products by Capillary Liquid Chromatography Using Molecularly Imprinted Solid-Phase Extraction

Capillary liquid chromatography with UV detection is proposed for the determination of 5-nitroimidazole residues in aquaculture products. The separation was carried out in a C18 column at 20 °C, using a mobile phase consisting of water and acetonitrile, at 7 μL/min and 320 nm as detection wavelength. Furthermore, full loop injection mode (8 μL) was selected and water was considered as injection solvent. The optimized method was applied to the monitoring of nine 5-nitroimidazoles, including three metabolites, in crab, salmon, prawn, and velvet swimming crab. Molecularly imprinted solid-phase extraction has been evaluated for sample cleanup. The method was characterized in all the matrices in terms of linearity (R ² ≥ 0.9964), precision (repeatability, RSD ≤ 7.9%, and reproducibility, RSD ≤ 11.1%) and trueness (recoveries between 80.4 and 108.7%). Decision limits, CCα, ranging from 0.2 to 1.5 μg/kg and detection capabilities, CCβ, from 0.2 to 1.8 μg/kg, were obtained.     

Simultaneous Determination of 11 Food Additives by Micellar Electrokinetic Capillary Chromatography

A micellar electrokinetic chromatographic (MEKC) method was developed for simultaneous determination of 11 food additives which are commonly used in beverage, yogurt, and candied fruit samples. An uncoated fused-silica capillary with 50 μm i.d. and 70 cm total length (effective length: 60 cm) was used for the separation. The separation buffer consisted of 20 mmol/L sodium tetraborate, 42 mmol/L boric acid (pH 8.83), and 100 mmol/L sodium deoxycholate. The separation voltage was 23 kV, and the detection wavelength was 214 nm. The limits of detection were in the ranges of 0.25 to 2.5 mg/L. The corrected peak areas (Ac) and the concentrations of the 11 additives showed linear relationships within the ranges of 0.6–400 mg/L with linear correlation coefficients (r) above 0.99. The recoveries ranging from 81.6 to 115.0 % with relative standard deviations (RSDs) all lower than 5 % were obtained, which demonstrated the accuracy of the proposed method. A Food Analysis Performance Assessment Scheme (FAPAS®) proficiency test sample was analyzed. The results showed that the current method with simple sample pretreatment could meet the needs for routine analysis of the 11 additives in beverage, yogurt, and candied fruit samples.     

Determination of Deoxynivalenol and Nivalenol in Wheat by Ultra-Performance Liquid Chromatography/Photodiode-Array Detector and Immunoaffinity Column Cleanup

An ultra-performance liquid chromatography (UPLC®) method has been developed for the simultaneous determination of deoxynivalenol (DON) and nivalenol (NIV) in wheat. Ground sample was extracted with water and the filtered extract was cleaned up through an immunoaffinity column containing a monoclonal antibody specific for DON and NIV. Toxins were separated and quantified by UPLC® with photodiode-array detector (λ?=?220 nm) in less than 3 min. Mean recoveries from blank wheat samples spiked with DON and NIV at levels of 100–2,000 μg/kg (each toxin) ranged from 85 to 95 % for DON and from 81 to 88 % for NIV, with relative standard deviations less than 7 %. Similar recoveries were observed from spiked samples when methanol/water (80:20, v/v) was used as extraction solvent. However, by using a wheat sample naturally contaminated with DON and NIV, the one-way analysis of variance (Student–Newman–Keuls test) between different extraction solvents and modes showed that water extraction provided a significant increase (P?<?0.001) in toxin concentrations (mean values of six replicate analyses) with respect to methanol/water (80:20, v/v). No significant difference was observed between shaking (60 min) and blending (3 min). The limit of detection (LOD) of the method was 30 μg/kg for DON and 20 μg/kg for NIV (signal-to-noise ratio 3:1). The immunoaffinity columns showed saturation of DON/NIV binding sites at levels higher than 2,000 ng in blank wheat extracts spiked with the corresponding amount of mycotoxin, as single mycotoxin or sum of DON and NIV. The range of applicability of the method was from LOD to 4,000 μg/kg, as single mycotoxin or sum of DON and NIV in wheat. The analyses of 20 naturally contaminated wheat samples showed DON contamination in all analyzed samples at level ranging from 30 to 2,700 μg/kg. NIV was detected in two samples at negligible toxin levels (up to 46 μg/kg). This is the first UPLC® method using immunoaffinity column cleanup for the simultaneous and sensitive determination of DON and NIV in wheat.     

Determination of Pesticide Residues in Golden Berry (<Emphasis Type="Italic">Physalis peruviana</Emphasis> L<Emphasis Type="Italic">.</Emphasis>) by Modified QuEChERS Method and Ultra-High Performance Liquid Chromatography-Tandem Quadrupole Mass Spectrometry

A fast and effective multiresidue method for the determination of 42 pesticides in golden berry was developed and validated. A modified QuEChERS method was established for sample preparation followed by ultra-high performance liquid chromatographic-tandem mass spectrometry (UHPLC-MS/MS) determination with electrospray ionization in a triple quadrupole system. Validation results were satisfactory, since the method presented recoveries between 70 and 114 % with relative standard deviations (RSD) <20 % for blank samples spiked from 5 to 25 μg kg^?1. The method limit of detection and limit of quantification were 1.5 and 5 μg kg^?1 _, respectively. Matrix effect ranged from ?32 to 218 % and was compensated using matrix-matched calibration. Method linearity was established from 2.5 to 100 μg kg^?1 with r ² ≥ 0.99. The proposed method combines the advantages of a simple and fast sample preparation step by a modified QuEChERS method with the high selectivity and sensitivity of the UHPLC-MS/MS system using selected reaction monitoring. The method was successfully applied to commercial samples, proving to be an efficient alternative for routine analysis. From the 16 analyzed samples, 13 presented residues of one or more pesticides (carbendazim, chlorpyrifos ethyl, dimethoate, propamocarb, and tebuconazole) in the concentration range of 2.0 to 55.6 μg kg^?1.     

Fast Preconcentration of Pesticide Residues in Oilseeds by Combination of QuEChERS with Dispersive Liquid–Liquid Microextraction Followed by Gas Chromatography-Mass Spectrometry

A fast, efficient, and simple method for determination of pesticide residues in pumpkin seeds has been developed combining QuEChERS and dispersive liquid–liquid microextraction (DLLME) followed by gas chromatography and mass spectrometry (GC-MS). Parameters affecting the DLLME performance such as solvent selection and volume of extractive and dispersive solvent, salt effect, and extraction time were studied. Under the selected conditions (50 μL extractive solvent chloroform, 1 mL QuEChERS extract, and 3 mL water), the developed method was validated. Linearity was evaluated at nine concentrations in the broad range of 0.1–500 μg/kg with correlation coefficients from 0.9842 to 0.9972. The relative standard deviations at lowest calibration level varied from 0.3 to 22 %. Under the optimum conditions, an enrichment factor was 6–17-fold and detection limits 0.01–12.17 μg/kg were achieved. Finally, the developed and validated method was successfully applied for the extraction and determination of pesticide residues in 16 real samples with 2 positive findings below maximum residue limits (MRL). Limits of detection (LODs) of the proposed method are below the MRLs established by the European Union.     

Simultaneous Determination of Ten Ginsenosides in American Ginseng Functional Foods and Ginseng Raw Plant Materials by Liquid Chromatography Tandem Mass Spectrometry

A method was established for simultaneous determination of ten ginsenosides (ginsenosides Rg1, Re, Rb1, Rf, Rb3, 20(S)-F1, 20(S)-F2, Rg3, 20(S)-Rh2, and pseudoginsenoside F11) in American ginseng functional foods and ginseng raw plant materials by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry. After samples were ultrasonically extracted with 60 % (v/v) methanol aqueous solution, centrifuged, and filtered, the analytes in sample solution were separated by a Hypersil Gold column (2.1?×?150 mm, 5 μm) at 25 °C with a programmed gradient elution. Mobile phases consisting of 0.01 % (v/v) formic acid aqueous solution and methanol were used for elution with a flow rate of 250 μL/min. Qualitative determination was completed by comparison with characteristic ion pairs and retention time of the targeted compounds using selective reaction monitoring mode. Digoxin was used as internal standard in positive ionization mode. The internal standard curves were used for quantification. The limits of detection of the method were from 1.0 to 5.0 mg/kg. The linear dynamic ranges covered from 10 to 5,000 μg/L (R ²?≥?0.99). Principal component analysis was used for distinguishing ginseng sources of the functional foods. Thirty-seven samples, including 11 American ginseng raw plants, 12 labeled American ginseng functional foods, 5 notoginsengs, 5 Asian ginsengs, and 4 red ginsengs, were analyzed by this method. The results showed that five labeled American ginseng functional foods might have quality defects and six functional foods might be adulterated. This method can be applied to quality control and ginseng source assessment of American ginseng functional foods.     

Determination of sterigmatocystin in foods in Japan: method validation and occurrence data

ABSTRACT

A survey of the contamination of foods by sterigmatocystin (STC) was performed by an analytical method based on LC-MS/MS. STC was extracted from samples with acetonitrile/water (85/15, v/v) and then purified with immunoaffinity columns. The method was validated by a small-scale inter-laboratory study using spiked wheat samples. Mean recoveries of STC were 100.3% and 92.5% from two samples spiked at 0.5 and 5.0 µg/kg, respectively. A total of 583 samples were analysed between 2016 and 2018, and STC was detected in 19.9% of all samples at >0.05 μg/kg (limit of quantification). The foods that were contaminated by STC were wheat flour, Job’s tears products, rye flour, rice, buckwheat flour, white sorghum, barley products, azuki bean and corn flour. STC was not found in beer or wine. The occurrence of STC in domestic wheat flour (44.4%), Job’s tears products (41.7%) and rye flour (29.9%) accounted for the three highest values. The highest mean concentrations were obtained for Job’s tears products (0.3 μg/kg) and rye flour (0.3 μg/kg). The maximum contamination level was present in a sample of rye flour (7.1 μg/kg). Although the contamination levels were low, these results indicate that STC frequently contaminates Japanese retail foods. A continuous survey is required to assess exposure to STC in Japan.     

Surfactant–Solvent-Based Quaternary Component Emulsification Microextraction Followed by High-Performance Liquid Chromatography for the Simultaneous Analysis of Benzimidazole Anthelmintics in Milk Samples

A simple surfactant-solvent-based quaternary component emulsification microextraction (SSEME) method combined with high-performance liquid chromatography–photodiode array detection has been developed for the extraction, preconcentration, and determination of four benzimidazole anthelmintic (i.e., oxfendazole, mebendazole, albendazole, and fenbendazole) residues in milk samples. The quaternary component solvent of SSEME carried out in 10 mL aqueous solution were Triton X-114 (emulsifier or carrier), acetonitrile (disperser solvent), and 1-octanol (extraction solvent). The surfactant has an important role in the enhancement of the extraction efficiency of the high polar analytes. For milk sample analyses, linearity was obtained in the range of 10–200 μg/L with the determination coefficients (R ²) higher than 0.996. Preconcentration factor was obtained in the range of 21–38, corresponding to limits of detection in the range of 2.6–9.9 μg/L. Intra-day (n?=?6) and inter-day (n?=?6?×?3) precisions in the sample studied were obtained with relative standard deviation below 8.8 %. The recoveries for the spiked target anthelmintics at different concentrations (25, 50, 100, and 150 μg/L) were obtained in the range 80.1–114.1 %. The proposed SSEME method has been demonstrated that is simple, effective, and reliable for the analysis of analytes in the samples studied and can be used as an alternative green analytical technique for benzimidazole analysis.     

Development and Validation of a Method for the Determination of Quinolones in Muscle and Eggs by Liquid Chromatography-Tandem Mass Spectrometry

In this study, the development and validation of a multiresidue method for the detection of 11 quinolones (marbofloxacin, norfloxacin, ciprofloxacin, danofloxacin, lomefloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid, nalidixic acid, flumequine) in muscle and eggs were reported. The method involved an extraction with a methanol/metaphosphoric acid mixture and a clean up by Oasis hydrophilic-lipophilic balance (HLB) cartridge. The validation was performed according to the Commission Decision 2002/657/EC. Linearity, specificity, decision limit (CCα), detection capability (CCβ), recovery, precision (repeatability and within-laboratory reproducibility), and ruggedness were determined. Depending on the analytes, CCα and CCβ ranged from 113 to 234 μg/kg and from 126 to 282 μg/kg in muscle samples, whereas in eggs, these parameters were between 5.6 and 7.4 μg/kg and between 6.1 and 9.8 μg/kg, respectively. In both the examined matrices, the recovery values were always higher than 90 % and precision, calculated as relative standard deviation, was equal to or lower than 16 % for repeatability and 23 % for within-laboratory reproducibility. The described method can be considered adequate for the simultaneous determination and quantification of quinolones in the tested food matrices.