Search results for "HPLC"
showing 10 items of 201 documents
Study of chemical changes produced in virgin olive oils with different phenolic contents during an accelerated storage treatment.
2009
Chemical changes produced in an extra virgin olive oil sample in the presence (EVOO) and absence (EVOOP) of its phenolic fraction during an accelerated storage treatment at 60 degrees C up to 7 weeks were studied. Modifications in phenol content, as well as changes in several quality parameters (free acidity, peroxide value, UV absorbance, fatty acid composition, oxidative stability index, and tocopherol content) were also evaluated under the same storage conditions and compared to those of the same sample deprived of phenolic compounds. When the phenolic extract of the EVOO was studied, a decrease of the antioxidants first present in the sample and an increase of the oxidized products were…
Chromatographically separable rotamers of an unhindered amide
2014
Surprisingly stable formamide rotamers were encountered in the tetrahydroisoquinoline and morphinan series of alkaloids. We investigated the hindered rotation around the amide bond by dynamic high-performance liquid chromatography (DHPLC) and kinetic measurements of the interconversion of the rotamers which can readily be separated by HPLC as well as TLC. The experimental results of the different methods were compared to each other as well as to results obtained by DFT calculations.
Antifungal effects of the bioactive compounds enniatins A, A1, B, B1
2010
To produce enniatin (ENs), Fusarium tricinctum CECT 20150 was grown in a liquid medium of potato (PDB), being mycotoxin purified by high performance liquid chromatography (HPLC) with a reverse phase semipreparative column using a mobile phase of acetonitrile/water using gradient condition. The purity of the ENs fractions was verified by analytical HPLC and LC/MS-MS. The pure fractions of ENs were utilized to study the biological activity on several mycotoxigenic moulds as Fusarium verticilloides, Fusarium sporotrichioides, Fusarium tricinctum, Fusarium poae, Fusarium oxysporum, Fusarium proliferatum, Beauveria bassiana, Trichoderma harzianum, Aspergillus flavus, Aspergillus parasiticus, Asp…
Inhibitory Activity of Shrimp Waste Extracts on Fungal and Oomycete Plant Pathogens
2021
(1) Background: This study was aimed at determining the in vitro inhibitory effect of new natural substances obtained by minimal processing from shrimp wastes on fungi and oomycetes in the genera Alternaria, Colletotrichum, Fusarium, Penicillium, Plenodomus and Phytophthora
Evaluation of sampling adsorbents and validation of a LC-HRMS method for determination of 28 airborne pesticides
2018
A new strategy for sampling, using a low-volume sampler, and determination of airborne pesticides by liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) has been developed. The trapping efficiency of three adsorbents (sandwich PUF-XAD2-PUF; XAD-2 and XAD-4) was tested for 33 currently used pesticides and the first adsorbent (PUF-XAD2-PUF) was selected because it presented the highest retention capacity without breakthrough. Selected PUF-XAD2-PUF had the following design: 5 g of Amberlite XAD-2 sandwiched between two cylinders of PUF (6.87 cm(3), height: 1.4 cm, diameter: 2.5 cm). A validation of the analytical methodology that includes microwave extraction with e…
Evaluation of antioxidant properties and assessment of genetic diversity of Capparis spinosa cultivated in Pantelleria Island.
2017
Capparis spinosa is a wild and cultivated bush, which grows mainly in the Mediterranean Basin. Unopened flower buds, called capers are used in the Mediterranean cuisine as flavoring for meat, vegetable and other foods. Several studies evaluated bioactive component and antioxidant activity of Capparis spinosa, increasing the market demand and the economic importance of capers.The aim of this work was to evaluate the contents of bioactive compounds in floral buds fermented in salt of C. spinosa collected from different areas of Pantelleria Island (Italy), testing the effect on healthy function as total antioxidant compounds. Hydrophilic extracts of C. spinosa from Pantelleria Island were char…
Chemical, Antioxidant and Biological Studies of Brassica incana subsp. raimondoi (Brassicaceae) Leaf Extract
2023
Brassica incana subsp. raimondoi is an endemic taxon present in a restricted area located on steep limestone cliffs at an altitude of about 500 m a.s.l. in eastern Sicily. In this research, for the first time, studies on the phytochemical profile, the antioxidant properties in cell-free and cell-based systems, the cytotoxicity on normal and cancer cells by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay, and on Artemia salina Leach, were performed. The total phenolic, flavonoid, and condensed tannin contents of the leaf hydroalcoholic extract were spectrophotometrically determined. Ultra-performance liquid chromatography—tandem mass spectrometer (UPLC-MS/MS) analysi…
Computer Aided Evaluation of HPLC (High Pressure Liquid Chromatography) with Fluorometric Detection
1982
A program system for automated HPLC measurements of vitamin A concentration is reported. This system provides for guidance of operators, for control of apparatus and for supervision of quality measurements.
PRELIMINARY STUDY ON QUANTIFICATION OF aS1-CASEIN VARIANTS IN GIRGENTANA GOAT BREED BY DIRECT CHROMATOGRAPHIC ANALYSIS OF MILK
2012
Goat αs1-casein is a highly polymorphic protein, coded by CSN1S1 gene. Nowadays, several alleles were identified and associated with different levels of αs1-casein in goat milk. Polymorphisms at αs1-casein locus have been shown to affect not only the quantity of this casein in goat milk, but also the structural and nutritional characteristics (hypoallergenic properties) and technological properties of the milk (1). The aim of this work was to separate and quantify the most common allelic variants of αs1-casein in milk of Girgentana goat breed, a Sicilian autochthonous breed, and to evaluate the effect of αs1-casein polymorphisms on casein content. The CSN1S1 A/01, B/E, F, and N alleles were…
Paediatric oral formulations: comparison of two extemporaneously compounded suspensions from tacrolimus capsules
2011
Study objectives: The objective of this study was to determine the stability of tacrolimus in extemporaneously compounded liquid formulations. Methods: Two sets of liquid formulations were prepared using two different vehicles: one set in sterile water and in simple syrup (1:1) and one set using equal volumes of commercially available suspending agent (Ora-Plus) and simple syrup. The concentration of tacrolimus in each formulation was 0.5 mg/mL. The preparations containing Ora-Plus were stored at 25°C, the formulations that were prepared with sterile water and simple syrup were stored under refrigeration at 4°C. Results: Samples were collected at regular time intervals over a period of 56 d…