RESUMEN
Objectives: Parabens, which are p-hydroxybenzoic acid esters, are used as preservatives in personal care products, pharmaceuticals, and food because of their antimicrobial activity. However, they are also classified as suspected endocrine disruptors and carcinogens. In the present study, we aimed to optimize an ultrasound and vortex-assisted dispersive liquid-liquid microextraction (DLLME) procedure for the simultaneous extraction of methyl, ethyl, isopropyl, propyl, isobutyl, and butyl parabens from personal care products and urine. Materials and Methods: The extraction solvent type, extraction solvent volume, disperser solvent volume, sodium chloride concentration, ultrasonication time, and vortex application time were evaluated to obtain optimum recoveries by ultrasound and vortex-assisted DLLME. Parabens were detected using a validated high performanc-liquid chromatography (HPLC) method with fluorescence detection. Method validation was performed by examining linearity, the limit of detection, limit of quantification, accuracy, and precision. Results: The limits of detection and quantification of the HPLC method were between 0.09-0.18 µg/mL and 0.28-0.54 µg/mL, respectively. Precision was examined as the relative standard deviation, which was 0.22-1.81% and 1.12-2.03% for intra- and interday studies. Recovery percentages were higher than 96.00%. Samples of two paraben-free personal care products and synthetic urine were spiked with the analyses at 0.02 µg/mL and were successfully analyzed using the developed procedure with recovery values higher than 82.00%. Conclusion: The proposed procedure provided quantification of selected parabens at 20 ng/mL in analyzed personal care products and urine matrices with good precision and accuracy.
RESUMEN
Anthraquinones exhibit a significant group of natural and synthetic quinone derivatives because of their biological activities and industrial applications. Rhamnaceae is one of the families known to contain different kinds of anthraquinones. In this study, it was aimed to quantify rhein, emodin, chrysophanol and physcion in fruits of Rhamnus petiolaris Boiss. & Balansa belonging to Rhamnaceae by solid phase extraction and high performance liquid chromatography with ultraviolet detection. The anthraquinones were separated using a C18 analytical column. Gradient elution was performed using a mobile phase consisted of 0.1% o-phosphoric acid solution and methanol. Analytes were detected at 254 nm. Calibration curves were prepared in the range of 0.25-5.00 µg/mL for rhein, chrysophanol, physcion, 1.00-50.00 µg/mL for emodin. Limits of detection and quantification were between 0.07-0.11 and 0.20-0.34 µg/mL, respectively. Relative standard deviations were ≤ 5.78% in repeatability and intermediate precision studies. Accuracy was determined as relative mean error (8.17-12.06%). Extraction was achieved by maceration with acetone and ethanol, followed by hydrophilic-lipophilic balance solid phase extraction. Recoveries were between 96.2 and 109.6%. The developed and validated method was successfully performed to quantify rhein, emodin, chrysophanol and physcion in R. petiolaris fruit extracts. Only physcion was not detected above limit of detection.
RESUMEN
A new solid phase extraction-high-performance liquid chromatography method with ultraviolet detection was developed and validated for the determination of three chlorogenic acids (5-O-caffeoylquinic, 3-O-caffeoylquinic and 4-O-caffeoylquinic acids) and six phenolic acids (caffeic, ferulic, sinapic, protocatechuic, p-hydroxybenzoic acid (PHBA) and vanillic acid (VA)) in coffee bean samples. Extraction was performed using hydrophilic-lipophilic balance cartridges. Separations were accomplished using a C18 guard column (10 × 2.1 mm, 3 µm) and a C18 analytical column (50 × 2.1 mm, 3 µm). o-Phosphoric acid solution (0.08%) and methanol/water/acetonitrile (85:10:5) solution were used as mobile phase with a gradient system. A UV detector was used at 325 nm for 5-O-caffeoylquinic, caffeic, 3-O-caffeoylquinic, 4-O-caffeoylquinic, ferulic, sinapic acids, and 215 nm for protocatechuic, PHBA and VA. Calibration equations and coefficients of determination were determined by least-squares method with weighting factor. Limits of detection and quantification were in the range of 0.15-0.69 and 0.46-2.09 mg/L, respectively. Precision and accuracy of the proposed method were investigated with coffee sample spiked at low, medium and high concentrations. The developed and validated method was applied for the determination of nine phenolic compounds in seven coffee bean samples from different origins with high accuracy and repeatability.