132 research outputs found
Dispersive liquid–liquid microextraction combined with high-performance liquid chromatography–tandem mass spectrometry for the identification and the accurate quantification by isotope dilution assay of Ochratoxin A in wine samples
No full textA novel approach for the rapid analysis of ochratoxin A (OTA) in wine samples is presented. Mycotoxin was extracted and concentrated from matrix using dispersive liquid–liquid microextraction (DLLME). The final extract is analyzed by liquid chromatography coupled to positive electrospray ionization tandem mass spectrometry employing [2H5]-ochratoxin A as internal standard. Some important parameters, such as the nature and volume of extraction solvent and dispersive solvent, and salt effect were investigated and optimized to achieve the best extraction efficiency and higher enrichment factor. Under the optimum extraction condition, the method provided enrichment factor around 80 times and showed a high sensitivity with method detection and quantification limits of 0.005 and 0.015 ng mL−1, respectively. To test the accuracy of the analytical procedure, the optimized method was applied to the analysis of reference material T1755 (naturally contaminated white wine), with excellent results (accuracy of 103%) and showing a good precision with a CV (n = 6) of 5.8%. The proposed method, which is demonstrated to be quick, cheap, accurate and highly selective, was successfully applied to the analysis of Italian wines
Editorial: The chemo-biological language of plants: exploring the diversity of specialized metabolites
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The Spread of Invasive and Poisonous Plants: A Lesson from Alkaloids
No full textInvasive plant species pose a significant threat to global biodiversity and ecosystems. Climate changes favor the spread of non-native plants, whether voluntary or accidentally introduced into a new environment, as these plants possess a greater ability to adapt to changing environments. The spreading of these alien species has a negative impact also on agro-ecosystems, on agricultural yields, and on the nutritional quality of food crops. The high metabolic plasticity of these plants helps them to adapt to new ecosystems, enabling them to succeed in competing with crops. In particular, many alien plants are producers of alkaloids. These molecules represent the main chemical defense to biotic stressors and also the major risk for human health. In this review, we focused on invasive plants producing tropane alkaloids (TAs) and pyrrolizidine alkaloids (PAs). We explored the potential role of these molecules in the fitness of invasive plants in the context of climate change and reviewed the knowledge regarding their biosynthesis steps and examined the mechanism of toxicity when accidentally ingested. Finally, we summarized the most efficient analytical and molecular methods to detect either alkaloid contamination or the presence of invasive plant contaminants, which are the source of these molecules, in food crops. Possible solutions and precautions to ensure food safety have been also proposed
Application of dispersive liquid–liquid microextraction for the determination of aflatoxins B1, B2, G1 and G2 in cereal products
No full textThe application of dispersive liquid-liquid microextraction (DLLME) technique for the rapid analysis of aflatoxins B(1), B(2), G(1) and G(2) in maize, rice and wheat products has been evaluated. After extraction of aflatoxins from cereal matrices with a mixture of methanol/water 8:2 (v/v), the analytes were rapidly transferred from the extract to another small volume of organic solvent, chloroform, by DLLME. Aflatoxins were determined using high performance liquid chromatography with florescence detection and photochemical post-column derivatization. Parameters affecting both extraction and DLLME procedures, such as extraction solvent, type and volume of DLLME extractant, volume of water and salt effect, were systematically investigated and optimized to achieve the best extraction efficiency. Under the optimal experimental conditions, the whole analytical method provides enrichment factors around 2.5 times and detection limits (0.01-0.17 mu g kg(-1)) below the maximum levels imposed by current regulation for aflatoxins in cereals and cereal products intended for direct human consumption. Recoveries (67-92%) and repeatability (RSD < 10, n = 3), tested in three different cereal matrices, meet the performance criteria required by EC Regulation No. 401/2006 for the determination of the levels of mycotoxins in foodstuffs. The proposed method was successfully applied to the analysis of retail cereal products with quantitative results comparable to the immunoaffinity chromatography (IAC). The main advantages of developed method are the simplicity of operation, the rapidity to achieve a very high sample throughput and low cost
Determination of organophosphorous flame retardants in fish tissues by matrix solid-phase dispersion and gas chromatography
No full textOrganophosphate esters (OPEs), utilized as flame retarding agents and/or plasticizers, are almost ubiquitous in environmental compartments, and biota and foods could be contaminated by bioaccumulation or during the treatment processes. A multiresidue method is proposed for the determination of 13 OPEs in fish tissues: analytes were simultaneously extracted and purified using the matrix solid phase dispersion technique and then determined by gas chromatography with nitrogen–phosphorus detection. The main parameters affecting extraction yield and selectivity, such as the type of dispersant material, clean-up co-sorbent, rinse and elution solvents, were evaluated to obtain lipid-free extracts and quantitative recoveries for OPEs. Under optimal conditions, 0.5 g of samples was dispersed with
2 g Florisil and 1 g anhydrous sodium sulphate and transferred to a solid phase extraction cartridge containing 1 g alumina. The lipids were removed using 5 mL n-hexane/dichloromethane (1:1) and analytes were recovered with 10 mL n-hexane/acetone (6:4) and directly analysed. The method developed provided recoveries
between 70 and 110% for different kinds of fish, and the day-to-day variability was between 1 and 9%. This procedure constitutes the first analytical method for the analysis of OPEs in a food matrix and it is applicable to analyse a large number of samples to evaluate the occurrence and sources of OPEs in biota and foods
Application of pressurized liquid extraction in the analysis of aflatoxins B1, B2, G1 and G2 in nuts.
No full textAflatoxins (AFs) B1, B2, G1 and G2 were extracted from nuts by using pressurized liquid extraction (PLE) and the PLE extracts were analyzed using HPLC with fluorescence detection using photochemical post-column derivatization without further cleanup procedures. Several extraction parameters such as temperature (25, 40, 60 and 80°C), pressure (500, 1000, 1500 and 2000 psi), solvent extraction mixture (acetone, acetonitrile, ethyl acetate and methanol), number of cycles (1 and 2), use of dispersing agents and cell size (5 and 11 mL) were investigated for their effects on the extraction performance. The results showed 60°C, 1500 psi, acetonitrile, one cycle and a cell size of 5 mL as most favorable PLE operating conditions. The proposed analytical method provides LODs below the maximum levels established by European Union regulations and the recoveries of the four AFs were between 77 and 93% at spiking levels of 4, 2 and 0.5 μg/kg for AFB1 and AFG1 and 1, 0.5 and 0.13 μg/kg for AFB2 and AFG2. Validation was carried out using certified reference materials. PLE has been applied for the first time to the analysis of AFs in nuts and offers the possibility for fast simple and accurate quantitative determination of studied mycotoxins
Phytochemical Extracts of <i>Dittrichia viscosa</i> (L.) Greuter from Agroecological Systems: Seed Antigerminative Properties and Effectiveness in Counteracting Alternaria Leaf Spot Disease on Baby-Leaf Spinach
No full textDittrichia viscosa (L.) Greuter subsp. viscosa (Asteraceae) is a perennial species naturally distributed in arid and marginal areas whose agroecological cultivation could be a useful innovation to produce quality biomass to extract phenolic-rich phytochemical blends. Here, biomass-yield trends were profiled at different growth stages under direct cropping, and inflorescences, leaves, and stems were submitted to water extraction and hydrodistillation. Then, four extracts were investigated for their biological activities in invitro and in planta assays. Extracts inhibited cress (Lepidium sativum)- and radish (Raphanus sativus)-seed germination and root elongation. All samples showed dose-dependent antifungal activity in the plate experiments, inhibiting up to 65% of the growth of the fungal pathogen Alternaria alternata, a leaf-spot disease agent of baby spinach (Spinacea oleracea). However, only the extracts from dried green parts and fresh inflorescences at the highest concentration significantly reduced (54%) the extent of Alternaria necrosis on baby spinach. UHPLC-HRMS/MS analysis revealed that the main specialized metabolites of the extracts are caffeoyl quinic acids, methoxylated flavonoids, sesquiterpene compounds such as tomentosin, and dicarboxylic acids, which may explain the observed bioactivity. Plant extracts obtained through sustainable methodology can be effective in biological agricultural applications
Ultra-preconcentration and determination of selected pharmaceutical and personal care products in different water matrices by solid-phase extraction combined with dispersive liquid–liquid microextraction prior to ultra high pressure liquid chromatography tandem mass spectrometry analysis
No full textPharmaceutical and personal care products (PPCPs) are one of the most important classes of emerging contaminants. The potential of ecological and environmental impacts associated with PPCPs are of particular concern because they continually penetrate the aquatic environment. This work describes a novel ultra-preconcentration technique for the rapid and highly sensitive analysis of selected PPCPs in environmental water matrices at ppt levels. Selected PPCPs were rapidly extracted and concentrated from large volumes of aqueous solutions (500 and 250 mL) by solid-phase extraction combined with dispersive liquid–liquid microextraction (SPE–DLLME) and then analyzed using UHPLC–MS/MS. Experimental parameters were carefully investigated and optimized to achieve the best SPE–DLLME efficiency and higher enrichment factors. The best results were obtained using the ternary mixture acetonitrile/methanol/dichloromethane 3:3:4, v/v/v, both as SPE eluent and DLLME extractant/dispersive mixture. DLLME aqueous solution (5% NaCl, 10 mg L−1 TBAB) was also modified to improve the extraction efficiency of more hydrophilic PPCPs. Under the optimal conditions, an exhaustive extraction for most of the investigated analytes (recoveries >70%), with a precision (RSD <10%) and very high enrichment factors were attained for different aqueous matrices (drinking, sea, river and wastewater). Method detection and quantification limits were at very low ppt levels and below 1 and 3 ng L−1, respectively, for 15 of selected PPCPs. The proposed analytical procedure offers numerous advantages such as the simplicity of operation, rapidity, a high enrichment factor and sensitivity. So it is suitable for monitoring and studies of occurrence of PPCPs in different environmental compartments
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