1,720,988 research outputs found
Ultra-Trace Determination of Sudan I, II, III, and IV in Wastewater by Solid-Phase Microextraction (SPME) and on-Line Solid-Phase Extraction (SPE) with High-Performance Liquid Chromatography (HPLC)
Full text linkTwo extraction/preconcentration methods are reported for the high-performance liquid chromatography (HPLC) determination of Sudan I, II, III, and IV in wastewater at trace (μg/L) and ultra-trace (ng/L) levels for the first time. The first approach, based on solid-phase microextraction (SPME), allows sub-μg/L determination of Sudan I and II, while Sudan III and IV are not detectable at these levels due to strong binding to dissolved organic matter. For Sudan I and II, the linearity was tested in the range from 0.5 to 50 μg/L and limits of detection (based on a signal-to-noise ratio of 3) and quantification (based on a signal-to-noise ratio of 10) of 0.2 and 0.5 μg/L, respectively, were estimated for both dyes. The on-line solid-phase extraction (SPE) using a C18 based enrichment precolumn was employed in the second approach. The only sample pretreatment employed was a required centrifugation step to remove suspended solids. In this case, the linearity was verified in the range from 50 to 500 ng/L for Sudan I, II, and III and from 100 to 500 ng/L for Sudan IV. The detection limits for a sample volume of 20 mL were on the order of 20 ng/L for Sudan I, 25 ng/L for Sudan II and III, and 30 ng/L for Sudan IV
Effect of a Chitosan-Based Packaging Material on the Domestic Storage of “Ready-to-Cook” Meat Products: Evaluation of Biogenic Amines Production, Phthalates Migration, and In Vitro Antimicrobic Activity’s Impact on Aspergillus Niger
No full textThe consumption of "ready-to-cook" foods has been experiencing rapid expansion due to modern lifestyles, and they are often sold in economical multipacks. These foods necessitate packaging that maintains their quality for extended periods of time during home storage once the original packaging is opened. This study evaluates a chitosan-based film derived from low- and high-molecular-weight (MW) chitosan in acetic acid without synthetic additives as an alternative packaging material for "ready-to-cook" beef burgers. The burgers were stored at 8 degrees C after being removed from their sales packaging. A commercial polyethylene (PE) film designed for food use, devoid of polyvinylchloride (PVC) and additives, served as the reference material. The production of six biogenic amines (BAs), indicative of putrefactive processes, was monitored. Additionally, the release of four phthalates (PAEs), unintentionally present in the packaging films, was assessed using solid-phase microextraction coupled with gas chromatography/mass spectrometry (SPME-GC/MS). Microbiological tests were conducted to investigate the antimicrobial efficacy of the packaging against Aspergillus Niger NRR3112. The results showed that the chitosan-based films, particularly those with low MW (LMW), exhibited superior meat preservation compared to the PE films. Furthermore, they released PAEs below legal limits and demonstrated the complete inhibition of fungal growth. These findings highlight the potential of chitosan-based packaging as a viable and effective option for extending the shelf-life and maintaining the quality of "ready-to-cook" meat products during domestic storage
Measurement of squalene in olive oil by fractional crystallization or headspace solid phase microextraction coupled with gas chromatography
Full text linkSqualene is the most abundant component in the unsaponifiable fraction of olive oil with strong antioxidant properties. Its concentration in olive oils varies between 0.2 and 16.2 g/kg depending on the cultivar(s) used. The propose of this work was to determine the effectiveness of two different extraction methods for squalene determination by gas chromatography (GC) coupled to a flame ionization detector (FID) or to mass spectrometry (MS). In a first approach, oil samples were dissolved in methanol/acetone mixture 7:3 (v/v) and triglycerides separated by fractional crystallization at −20°C. The organic layer was removed, reduced to dryness and the residue reconstituted in n-heptane (containing squalane as external standard) and analyzed by GC-FID. A headspace (HS) solid phase microextraction (SPME) GC-MS method has been also developed in order to have an environmentally friendly (i.e. solventless) extraction procedure. The linear range investigated with both methods was 1.0-10 g/kg. Within-day and between days precision values, expressed as RSD%, were 4 and 7% (GC-FID), and 3 and 6% (GC-MS), respectively. The limit of detection (LOD) at a signal-to-noise (S/N) ratio of 3 were 0.019 (GC-FID) and 0.003 (GC-MS) g/kg; the limit of quantification (LOQ) calculated at S/N = 10 were 0.063 (GC-FID) and 0.008 (GC-MS) g/kg, well below the typical squalene concentration levels found in olive oils. The obtained percentage recoveries were 70 ± 2 (GC-FID) and 98 ± 3 (GC-MS), and were not concentration dependent. The potential of the method has been demonstrated by the analysis of several different olive oil samples produced from different cultivars and different locations
Acid/Base Gas/Liquid Adsorption Properties of Carbon Black Modified in NH3/O2 RF Glow Discharges
No full textSolid phase microextraction-gas chromatography mass spectrometry: a fast and simple screening method for the assessment of organophosphorus pesticides residues in wine and fruit juices
No full textA SPME-GCMS method for the determination of a mixture of organophosphorus pesticides (phorate, diazinon, methylparathion,
fenitrothion, malathion, fenthion, ethyl-parathion and methidathion) in wine and different fruit juices was developed.
The procedure is solvent-free, simple (direct SPME without further sample pre-treatment) and highly sensitive. Estimated LOD and
LOQ ranged from 2 to 33 ng/ml and from 7 to 109 ng/ml, respectively, in wine, and from 2 to 90 ng/ml and from 7 to 297 ng/ml,
respectively, in fruit juices. LOQ achieved by the present method are almost always below the maximum residue levels recommended
by the European legislation
Solid-Phase Microextraction - Gas Chromatography Mass Spectrometry: a Fast and Simple Screening Method for the Assessment or Organophosphorus Pesticides Residues in Wine and Fruit Juices
No full textA SPME-GCMS method for the determination of a mixture of organophosphorus pesticides (phorate, diazinon, methylparathion, fenitrothion, malathion, fenthion, ethyl-parathion and methidathion) in wine and different fruit juices was developed. The procedure is solvent-free, simple (direct SPME without further sample pre-treatment) and highly sensitive. Estimated LOD and LOQ ranged from 2 to 33 ng/ml and from 7 to 109 ng/ml, respectively, in wine, and from 2 to 90 ng/ml and from 7 to 297 ng/ml, respectively, in fruit juices. LOQ achieved by the present method are almost always below the maximum residue levels recommended by the European legislation
Natural stones coated with a protective layer, process for their production and plasmochemical reactor
No full textAnalysis and Characterization of the Extracellular Vesicles Released in Non-Cancer Diseases Using Matrix-Assisted Laser Desorption Ionization/Mass Spectrometry
No full textThe extracellular vesicles (EVs) released by cells play a crucial role in intercellular communications and interactions. The direct shedding of EVs from the plasma membrane represents a fundamental pathway for the transfer of properties and information between cells. These vesicles are classified based on their origin, biogenesis, size, content, surface markers, and functional features, encompassing a variety of bioactive molecules that reflect the physiological state and cell type of origin. Such molecules include lipids, nucleic acids, and proteins. Research efforts aimed at comprehending EVs, including the development of strategies for their isolation, purification, and characterization, have led to the discovery of new biomarkers. These biomarkers are proving invaluable for diagnosing diseases, monitoring disease progression, understanding treatment responses, especially in oncology, and addressing metabolic, neurological, infectious disorders, as well as advancing vaccine development. Matrix-Assisted Laser Desorption Ionization (MALDI)/Mass Spectrometry (MS) stands out as a leading tool for the analysis and characterization of EVs and their cargo. This technique offers inherent advantages such as a high throughput, minimal sample consumption, rapid and cost-effective analysis, and user-friendly operation. This review is mainly focused on the primary applications of MALDI-time-of-flight (TOF)/MS in the analysis and characterization of extracellular vesicles associated with non-cancerous diseases and pathogens that infect humans, animals, and plants
Simultaneous Determination of Quercetin and Trans-Resveratrol in Winemaking Waste by Solid Phase Microextraction Coupled to High-Performance Liquid Chromatography with Fluorescence and Ultraviolet Detection
No full textA solid phase microextraction (SPME) method coupled with liquid chromatography (LC) and fluorescence/ultraviolet-diode array detection was developed for the simultaneous determination of quercetin and trans-resveratrol. The chromatographic, detection, and SPME extraction/desorption conditions were systematically optimized. The performance of four commercial SPME fibers—polyacrylate (PA), polyethylene glycol (PEG), polydimethylsiloxane (PDMS), and polydimethylsiloxane-divinylbenzene (PDMS-DVB)—was evaluated and compared with a homemade polydopamine (PDA)-coated fiber. While all of the fibers successfully extracted the target analytes, their efficiencies varied significantly. The PA, PEG, and PDA fibers demonstrated superior performance, exhibiting wide linearity ranges (0.03–1 μg/mL (PA and PEG) and 0.06–1 μg/mL (PDA) for quercetin, 0.01–1 μg/mL for trans-resveratrol); high sensitivity (LODs of 0.01 μg/mL (PA and PEG) and 0.02 μg/mL (PDA) for quercetin, 0.003 μg/mL for trans-resveratrol); and excellent precision. Among these, the polyacrylate coating delivered the best analytical performance and was selected for further application. The optimized method was applied to analyze winemaking by-products (seeds, skins, and stalks) using SPME on ethanol-macerated extracts subjected to brief ultrasonication. Quercetin and trans-resveratrol were quantified in pomace extracts at concentrations of 104.3 ± 8.2 μg/g and 38.5 ± 4.1 μg/g, respectively. Recovery experiments confirmed the method’s accuracy, with recoveries of 99.1 ± 7.4% for quercetin and 98.5 ± 9.8% for trans-resveratrol. This study establishes a reliable, sensitive, and efficient approach for the determination of these bioactive compounds in complex matrices, with potential applications in the food and pharmaceutical industries
Supercritical Fluid Extraction of Bioactive Components from Apple Peels and Their Modulation of Complex I Activity in Isolated Mitochondria
No full text: Supercritical fluid extraction (SFE) was used to extract bioactive compounds from apple (Malus domestica) peel waste from three different Italian cultivars. The bioactive fractions were extracted applying a temperature of 60 °C and a pressure of 250 bar for 15 min with 20% ethanol as co-solvent, at a flow rate of 2 mL/min. The total polyphenol (TP), anthocyanin (TA), ascorbic acid (AA), and antioxidant activity contents (TACs) were measured, while chromatographic analyses were performed to highlight the differences between the extracts. The Stark cultivar had the highest levels of polyphenols, anthocyanins, and ascorbic acid, while the Royal Gala cultivar showed the highest total antioxidant activity. SFE extracts were then tested for their effect on the mitochondrial NADH-ubiquinone oxidoreductase (Complex I) activity on mitochondria isolated from human embryonic kidney cells (HEK239). The Stark extract showed the most positive response in terms of NADH oxidation. The results obtained in this work highlight the potential of apple peel waste as a source of functional phytocompounds and suggest that Stark cultivar extracts may be exploited for pharmacological applications. This study supports the circular bioeconomy by promoting the use of waste products as a valuable resource
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