mass spectrometry method is developed and validated for the simultaneous quantitation of three major phenolic acids including 1,5-dicaffeoylquinic acid (1,5-DCQA), 3,4-dicaffeoylquinic acid (3,4DCQA), and 3,5-dicaffeoylquinic acid (3,5-DCQA) in rat plasma. All analytes and internal standard (bergeninum) are extracted from plasma samples by liquid–liquid extraction with isopropanol. The chromato...

Here we evaluated the use of internal reference compounds for the rapid assessment of reactions performed in solid-phase. An internal reference compound (commercially available) was bound to the resin, together with the substrate, and cleaved with the products after completion of the reaction. The peak area of the reference compound in the HPLC-UV chromatograms can be correlated directly with t...

Investigation into the use of sodium, para-fluorobenzoate (p-FB) as a 12-3-12 Br Gemini surfactant counter ion was studied. The critical micelle concentration of the 12-3-12 Br surfactant was determined to be 1.0221mM using fluorescence and conductivity measurements. Varying solutions of Na + , p-fluorobenzoate from 0 to 10 mM in 2mM increments were prepared in a constant 10 mM 12-3-12 Br surfa...

A novel negative pressure and microwave assisted extraction technique (NMAE) was first proposed and applied for extraction of phenolic compounds from pyrola. [C₄MIM]BF₄ aqueous solution was selected as extraction solvent. Optimal extraction conditions were microwave power 700 W, negative pressure -0.07 MPa, temperature 40 °C, liquid-solid ratio 20 : 1, ionic liquid (IL) concentration 0.5 M, ext...

Solanum lycocarpum (Solanaceae) is native to the Brazilian Cerrado. Fruits of this species contain the glycoalkaloids solasonine (SN) and solamargine (SM), which display antiparasitic and anticancer properties. A method has been developed for the extraction and HPLC-UV analysis of the SN and SM in different parts of S. lycocarpum, mainly comprising ripe and unripe fruits, leaf, and stem. This a...

This study involves the incorporation of a commercially available Phenomenex Onyx C18 monolith column into the separation and detection of oxidative DNA damage. It includes thorough investigation of monolith performance and a comparison of the performance of monolith columns with a commercially available packed Restek reverse phase Ultra C18 column for the separation of DNA bases and nucleoside...

270 samples of different types of pasta and cereal products, distributed in a nursery school canteen in Milan (Italy), were analyzed to estimate the occurrence of ochratoxin A. OTA was found in all analyzed samples (100%), 39 samples exceeded the maximum limit established by European Commission Regulation for OTA in the foodstuffs listed in the relevant category. The mean concentration of ochra...

A simple HPLC-UV method has been developed and validated for the quantification of ellagic acid (EA) in ethanol extracts of Eugenia uniflora L. (Myrtaceae) leaves. The ultrasound-assisted extraction (UAE) optimization was performed using a Box Behnken design (33) combined with response surface methodology to study the effects of the ethanol concentration (%, w/w), extraction time (minutes), and...

An HPLC-UV/MS method has been developed to identify and quantify flame retardants in post-consumer plastics from waste of electric and electronic equipment (WEEE). Atmospheric pressure chemical ionisation spectra of 15 brominated and phosphate-based flame retardants were recorded and interpreted. The method was applied to detect flame retardant additives in polymer extracts obtained from pressu...