The aim of this research was to investigate the chemical composition of Coreopsis tinctoria Nutt. fruits extract, to highlight the potential of ultrasound assisted extraction in the fast preparation of extracts rich in polyphenols using different solvents (55%, 78% and 96% hydrous ethanol) and to evaluate the antioxidant potential of formulated extracts. LC-MS/MS was used to characterize the ethanolic extract from Coreopsis tinctoria Nutt. dried fruits. The extract contains different flavonoids (marein, flavanomarein, quercetagetin-7-O-glucoside, okanin aurone, leptosidin, luteolin, apigenin) and phenolic acids (chlorogenic acid, caffeic acid). Several parameters that could affect extraction efficiency were evaluated. Finally, this study focused on determination of plant extracts total phenolic content and their antioxidant capacity. The experimental results allowed the selection of the optimum operating parameters leading to the highest total polyphenolic content, expressed as gallic acid equivalents, and avoiding the degradation of phenolic compounds (ethanol 55%; extraction temperature 323.15 K, extraction time 30 min, liquid/solid ratio 20/1). A good relationship between total phenolic content and antioxidant capacity was obtained.

The present study was focused on the preparation and characterization of different topical oil in water emulsions based on natural ingredients such as collagen hydrolysate and vegetable oils mixtures. As oil phases, mixtures of coconut, almond, jojoba, avocado oils (in different ratios) were used while the water phase consisted in lavender water. As emulsifier, a plant based product containing glyceryl stearate and potassium stearate was incorporated (in the concentration range 4–5 %), while as rheology modifier xanthan gum was used (in the concentration range 0.2–1 %). As preservatives, Cosgard (containing benzyl alcohol, salicylic acid, glycerol, ascorbic acid) and mixtures of two essential oils (lemon and lavender) were selected. The designed formulations were assessed by means of their physico-chemical properties (pH, viscosity, thixotropic behavior), optical microscopy analysis and sensorial characteristics. The obtained emulsions were found to present pseudoplastic and thixotropic behaviors, adequate for cosmetic skin care product formulations.

A simple accurate kinetic spectrophotometric method was developed for the determination of nitrite based on its catalytic effect on the redox reaction between tropaeolin 00 and bromate in acid medium. Nitrite was determined by measuring the decrease in the absorbance of tropaeolin 00 at 530 nm by a fixed time method, after 30 s from the initiation of the reaction. The calibration graph was linear in the range 6–500 ng mL⁻¹ of nitrite and the detection limit was 2 ng mL⁻¹. The proposed method is selective and is useful for the determination of nitrite in drinking water samples.

A method for the determination of Fe(III) at trace levels is described. Thus prior to the spectrophotometric determination, a preconcentration of the trace amounts of iron(III) using a chelate forming resin is proposed. A strong base anion-exchange resin (Dowex 2X4) loaded with Ferron (7-iodo-8-hydroxyquinoline-5-sulphonic acid) was used for Fe(III) preconcentration, at pH 2.2. After desorption with 5% ascorbic acid in 0.5 M HCl, the analyze (converted from Fe(III) to Fe(II) was determined spectrophotometrically at 510 nm as Fe(II)-o-phenanthroline complex. The accuracy of the proposed method was verified by comparing the obtained results with those obtained using AAS with the standard addition method. The sensitivity of the spectrophotometric method (after preconcentration) was 0.01?g Fe(III)/ml. The recovery for iron(III) at the 7?g/l level was 97%.

A simple and sensitive method for the spectrophotometric determination of diosmin has been developed, and optimum reaction conditions along with other analytical parameters have been evaluated. Diosmin, as a phenolic compound, reacts with sodium nitroprusside and hydroxylamine hydrochloride in a basic medium to give a green-colored product. At analytical wavelength of 763 nm, Beer's law is obeyed over the concentration range 2–140 μg mL⁻¹ of diosmin with a correlation coefficient of 0.9997. The molar absorptivity is 9671 L mol⁻¹ cm⁻¹. The limits of detection (LOD) and quantification (LOQ) are 0.05 and 0.2. μg mL⁻¹, respectively. The method has been successfully applied to the determination of diosmin in a commercial pharmaceutical preparation. The results were compared favorably with those obtained by the 4-aminoantipyrine method.