Search results for " HPLC"

RpeakChrom: Novel R package for the automated characterization and optimization of column efficiency in high-performance liquid chromatography analys…

2017

Characterization of chromatographic columns using the traditional van Deemter method is limited by the necessity of calculating extra-column variance, issue particularly relevant when modeling asymmetrical peaks eluted from monolithic columns. A novel R package that implements Parabolic Variance Modified Gaussian approach for accurate peak modeling, van Deemter equation and two alternatives approaches, based on van Deemter, has been developed to calculate the height equivalent to a theoretical plate (HETP). To assess package capabilities conventional packed reverse-phase and monolithic HPLC columns were characterized. Peaks eluted from the monolithic column showed a high value of factor asy…

Comparison of monolithic and microparticulate columns for reversed-phase liquid chromatography of tryptic digests of industrial enzymes in cleaning p…

2011

Abstract Enzymes of several classes used in the formulations of cleaning products were characterized by trypsin digestion followed by HPLC with UV detection. A polymeric monolithic column (ProSwift) was used to optimize the separation of both the intact enzymes and their tryptic digests. This column was adequate for the quality control of raw industrial enzyme concentrates. Then, monolithic and microparticulate columns were compared for peptide analysis. Under optimized conditions, the analysis of tryptic digests of enzymes of different classes commonly used in the formulation of cleaning products was carried out. Number of peaks, peak capacity and global resolution were obtained in order t…

ATP distribution and localization of mitochondria in Suberites domuncula (Olivi 1792) tissue

2011

SUMMARY The metabolic energy state of sponge tissue in vivo is largely unknown. Quantitative bioluminescence-based imaging was used to analyze the ATP distribution of Suberites domuncula (Olivi 1792) tissue, in relation to differences between the cortex and the medulla. This method provides a quantitative picture of the ATP distribution closely reflecting the in vivo situation. The obtained data suggest that the highest ATP content occurs around channels in the sponge medulla. HPLC reverse-phase C-18, used for measurement of ATP content, established a value of 1.62 μmol ATP g–1 dry mass in sponge medulla, as opposed to 0.04 μmol ATP g–1 dry mass in the cortex, thus indicating a specific and…

Phytochemical profile and antioxidant properties of the edible and non-edible portions of black sapote (Diospyros digyna Jacq.)

2022

This study evaluated the phytochemical profile and antioxidative properties of the edible and non-edible portions of black sapote. The phytochemical analysis highlighted the presence of several bioactive compounds, differently distributed among peel, pulp and seeds. In particular, the peel resulted rich of flavan-3-ols and proanthocyanidins, whereas seeds contained high amount of organic acids, including ferulic, citric and sinapic acids. Concerning functional properties, both edible and non-edible portions showed a significant prevention of lipid peroxidation in a cell-based model. Moreover, the results suggested that the antioxidant protection involved both redox active properties and gen…

Are analysts doing method validation in liquid chromatography?

2014

International audience; Method validation is being applied in the reported analytical methods for decades. Even before this protocol was defined, authors already somehow validated their methods without full awareness. They wished to assure the quality of their work. Validation is an applied approach to verify that a method is suitable and rugged enough to function as a quality control tool in different locations and times. The performance parameters and statistical protocols followed throughout a validation study vary with the source of guidelines. Before single laboratory validation, an analytical method should be fully developed and optimized. The purpose of the validation is to confirm p…

INFLUENCE OF BIOTIC AND ABIOTIC FACTORS ON QUALITY AND SECONDARY METABOLITES OF ‘VALENCIA’ ORANGE FRUITS

2014

Chemical composition, cytotoxic effects, antimicrobial and antibiofilm activity of Artemisia arborescens (Vaill.) L. growing wild in the province of …

2022

Artemisia arborescens (Vaill.) L. is a perennial shrubby plant growing along the coastal strips of the Mediterranean region. It is used in traditional medicine. Its essential oil and solvent extracts exhibit a very interesting chemotherapeutic potential, which makes this plant useful in maintaining human health. The goal of this study was to determine the phytochemical composition of the petroleum ether and methanol extracts, as well as to evaluate anticancer activities and antimicrobial and biofilm formation reduction. Thirty-nine phytochemical compounds in negative ion mode, and 25 in positive ion mode were identified by HPLC-ESI-QTOF-MS. All four extracts reduced the viability of human M…

Influenza della tostatura e della preparazione del caffè sul contenuto di Ocratossina A determinata mediante HPLC-FD

2008

HPLC-DAD-ESI-MS2analytical profile of extracts obtained from purple sweet potato after green ultrasound-assisted extraction

2016

International audience; Ultrasound pre-treatment (UAE) was applied to assist the extraction of valuable compounds (polyphenols (especially anthocyanins), and proteins) from purple sweet potato (PSP). Under optimum conditions (ultrasound time (40 min); supplementary hot extraction (80 °C) up to 120 min; pH: 2.5; ethanol concentration: 58%), the highest concentrations of polyphenols (3.877 mg/g), anthocyanins (0.293 mg/g), and proteins (0.753 mg/g) were found, with minimal specific energy consumption (8406 J/mg).Moreover, anthocyanin and non-anthocyanin polyphenols in PSP extract from optimized extraction temperature were identified using HPLC-DAD-ESI-MS2. The major identified anthocyanins we…

Moringa oleifera Leaf Powder as Functional Additive in Cookies to Protect SH-SY5Y Cells

2021

The aim of this work is the evaluation of the addition of Moringa leaf powder (MLP) in cookies in terms of antioxidant properties, dough processability and sensorial properties of the cookies. The total content of biophenols and flavonoids in MLP was detected and the identification of the bioactive molecules was performed by HPLC-ESI-TOF-MS measurements, before and after oven treatment at 180 ◦C for 20 min. After a preliminary evaluation of the MLP water soluble fraction (MLPsf) cytotoxicity, its protective effect against an oxidative injury induced in the SH-SY5Y cells was assessed. Data evidence that the bioactive molecules present in MLPsf are effective in preventing ROS production and i…