Utilization of inverted dispersive liquid–liquid microextraction followed by HPLC-UV as a sensitive and efficient method for the extraction and determination of quercetin in honey and biological samples

Analytical Methods for the Determination of Quercetin and Quercetin Glycosides in Pharmaceuticals and Biological Samples

Flavonoids are plant-derived compounds that have several health benefits, including antioxidative, anti-inflammatory, anti-mutagenic, and anti-carcinogenic effects. Quercetin is a flavonoid that is widely present in various fruits, vegetables, and drinks. Accurate determination of quercetin in different samples is of great importance for its potential health benefits. This review, is an overview of sample preparation and determination methods for quercetin in diverse matrices. Previous research on sample preparation and determination methods for quercetin are summarized, highlighting the advantages and disadvantages of each method and providing insights into recent developments in quercetin sample treatment. Various analytical techniques are discussed including spectroscopic, chromatographic, electrophoretic, and electrochemical methods for the determination of quercetin and its derivatives in different samples. UV-Vis (Ultraviolet-visible) spectrophotometry is simple and inexpensive but lacks selectivity. Chromatographic techniques (HPLC, GC) offer selectivity and sensitivity, while electrophoretic and electrochemical methods provide high resolution and low detection limits, respectively. The aim of this review is to comprehensively explore the determination methods for quercetin and quercetin glycosides in diverse matrices, with emphasis on pharmaceutical and biological samples. The review also provides a theoretical basis for method development and application for the analysis of quercetin and quercetin glycosides in real samples.

Green and cost-effective extraction techniques of quercetin from mixture of nutraceuticals with yield analysis via spectrophotometry and high performance liquid chromatograph methods

BACKGROUND

Extraction is the leading critical stage in the analysis of nutraceuticals. Ginkgo biloba (GB) has gained an interest because of its therapeutic usages.

OBJECTIVES

Development of four cost effective extraction techniques for extraction of quercetin from GB in mixture of nutraceuticals sachet. These techniques are solid phase extraction (SPE), liquid-liquid extraction (LLE), inverted dispersive liquid-liquid microextraction (IDLLME) and QuEChERS.

METHODS

Direct spectrophotometry was used to monitor the recovery of the standard quercetin throughout the optimization steps. HPLC-UV method of analysis was optimized to quantify the yields from the extracts present in the complicated sachets. The presented study was assessed by analytical eco-scale assessment (ESA) and National Environmental Method Index (NEMI) for greenness in comparison with literature.

RESULTS

Only SPE showed the best cleanup outcomes. ESA and NEMI showed an adequate greenness of proposed extraction protocol.

CONCLUSION

Quercetin (marker for GB) extraction from market nutraceutical sachets is considered an exemplary for analysis in quality control of nutraceuticals. Regarding the greenness results, the proposed method of extraction is grander even with adequate greenness as the extraction was one-step, in comparison with multi-steps in previously published protocols. Accordingly, it is recommended to be used in routine extraction and analysis of such kind of nutraceuticals.

HIGHLIGHTS

Four extraction protocols had been developed. For GB ternary sachets, proper recovery was obtained from C18 SPE. The assessment of greenness of the proposed protocol guaranteed the superiority of the presented study. Safer sorbents and chemicals favor to be used for routine extraction of nutraceuticals.

An environmentally friendly and novel amine-based liquid phase microextraction of quercetin in food samples prior to its determination by UV-vis spectrophotometry

A novel and environmentally-friendly method, which includes determination of trace amounts of quercetin in samples by using UV-vis spectrophotometry after enrichment with amine-based liquid phase microextraction (LPME), has been developed. As extraction solvent, N,N-dimethyl-n-octylamine has been used and the quercetin concentration in extraction phase was determined by UV-vis spectrophotometry at 382.5 nm. Important analytical parameters such as pH, extraction solvent type and volume, sample volume, extraction time were optimized by the method. Quercetin in the sample solution was extracted to 200 μL of N,N-dimethyl-n-octylamine phase at pH 4.0. The detection limit (LOD) and the quantitation limit (LOQ) values for quercetin were calculated as 0.07 μg·mL^-1 and 0.24 μg·mL^-1, respectively. Accuracy studies for the food samples was carried out by addition and recovery experiments. The developed method has been successfully applied to different food samples including spinach, green pepper, red onion and dill weed.

A new hybrid nanocomposite electrode based on Au/CeO2-decorated functionalized glassy carbon microspheres for the voltammetric sensing of quercetin and its interaction with DNA

A new hybrid composite containing cerium oxide nanoparticle (CeO2NP) and gold nanoparticle (AuNP)-decorated functionalized glassy carbon microspheres (FGCM) was synthesized (Au/CeO2@FGCM). As a result, an Au/CeO2@FGCM-paraffin oil paste electrode (PE) (Au/CeO2@FGCM-PE) was fabricated and employed for the voltammetric sensing of quercetin (QRT). The structure and surface morphology of Au/CeO2@FGCM were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Cyclic voltammetry (CV), square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS) were employed for the investigation of the electrochemical behavior of Au/CeO2@FGCM-PE. Under the optimum conditions, the SWV oxidation peak current showed linear dependence on the QRT concentration in the range from 48 nM to 1.09 μM. The achieved limits of detection and quantitation were 0.37 nM and 1.22 nM, respectively. Au/CeO2@FGCM-PE was reproducible, sensitive and stable and displayed anti-interference ability for various common interferents. The proposed method was also successfully applied for real sample analysis. The QRT content extracted from natural sources was determined, and satisfactory results were achieved. Furthermore, the interaction of QRT with salmon testes and calf thymus dsDNA (st-DNA and ct-DNA) on Au/CeO2@FGCM-PE was studied by CV and SWV. The corresponding binding constant (K), surface concentration (Γ), and Gibbs free energy (ΔG°) were computed for the free QRT and the bound QRT-dsDNA complex. The calculated K values for the QRT-ct-DNA and QRT-st-DNA complexes were found to be 6.24 × 105 M-1 and 3.63 × 105 M-1, respectively, which revealed that QRT strongly interacted with ct-DNA compared to that with st-DNA. The decreased intensity of the QRT oxidation peak resulting from its interaction with dsDNA provides a chance to use QRT as a new indicator to analyze ct-DNA and st-DNA.

Vortex assisted-ionic liquid dispersive liquid-liquid microextraction and spectrophotometric determination of quercetin in tea, honey, fruit juice and wine samples after optimization based on response surface methodology

The aim of our study is to develop a new vortex assisted-ionic liquid dispersive liquid-liquid microextraction (VA-IL-DLLM) method for preconcentration and determination of the quercetin in tea, honey, fruit juice and wine samples by spectrophotometry. The method is based on pH sensitive ion-pair formation between quercetin and rhodamine B at pH 6.5 by donor-acceptor mechanism, and then dispersion of the complex in the fine-drops of ionic liquid (IL). In this context, the effects of pH, concentrations of ion-pairing reagent, the IL, vortex time and dispersive solvent type on the preconcentration process of quercetin were investigated using a 2-level-5-factor central composite half fraction design (CCD) as experimental design for response surface methodology (RSM). Quantitative model was developed to determine the quercetin in food samples, and it is verified by analysis of variance (ANOVA) at a 95% confidence level (P < 0.05). Response surface plots and contour plots obtained by the model are used to determine the interactions of experimental variables. After the optimization, calibration graph was obtained between 35 and 750 μg L^-1 with the detection limit of 10.2 μg L^-1. The recovery and relative standard deviations (RSD%) were in range of 94-104%, and in range of 2.5-4.2%, respectively. The accuracy and precision of the method were tested by the experimental studies such as recoveries, intermediate precision, trueness and expanded uncertainty. A comparison of the current results to those reported for other studies is also presented.

Fluorometric determination of quercetin by using graphitic carbon nitride nanoparticles modified with a molecularly imprinted polymer

The authors describe a fluorescent probe for sensitive and selective determination of quercetin, an indicator for the freshness of drinks. The probe consists of silica ball encapsulated graphitic carbon nitride (g-C₃N₄) modified with a molecularly imprinted polymer (MIP). It was synthesized via reverse microemulsion. The resulting MIP@g-C₃N₄ nanocomposite was characterized by fluorescence spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray powder diffraction. Quercetin quenches the fluorescence of the MIP@g-C₃N₄ probe. The effect was used to quantify quercetin in grape juice, tea juice, black tea, and red wine by fluorometry (λ_exc = 350 nm, λ_em = 460 nm). Response is linear in the 10-1000 ng mL^-1 quercetin concentration range. The detection limit is 2.5 ng mL^-1, recoveries range between 90.7 and 94.1%, and relative standard deviations are between 2.1 and 5.5%. Graphical abstract Schematic of the synthesis of the MIP@g-C₃N₄ by a reverse microemulsion method. The probe was applied for the selective recognition and fluorometric determination of quercetin.

Cu- and S- @SnO2 nanoparticles loaded on activated carbon for efficient ultrasound assisted dispersive µSPE-spectrophotometric detection of quercetin in Nasturtium officinale extract and fruit juice samples: CCD-RSM design

A simple, rapid, and efficient method of dispersive micro solid phase extraction (D-μ-SPE) combined with UV-Vis spectrophotometry via ultrasound-assisted (UA) was applied for the determination and preconcentration of quercetin in extract of watercress (Nasturtium officinale), fruit juice and water samples. The sorbent in this method was synthesized by doping copper and sulfide into the tetragonal structure of SnO₂-nanoparticles (Cu- and S- @SnO₂-NPs) and subsequently loading it on activated carbon (AC). The D-μ-SPE parameters with direct effect on the extraction efficiency of the targeted analyte, such as sample pH, volume of eluent, sorbent mass and ultrasound time were optimized using central composite design method. Under optimized conditions, the calibration graph for quercetin was linear in the range of 20-4000 ng mL^-1; the limit of detection and quantitation were 4.35 and 14.97 ng mL^-1, respectively and the enrichment factor was 95.24. Application of this method to analyze spiked extract, fruit juice and water samples resulted in acceptable recovery values ranging from 90.3% to 97.28% with intra-day and inter-day relative standard deviation values lower than 6.0% in all cases. Among the equilibrium isotherms tested, Langmuir was found to be the best fitted model with maximum sorption capacity of 39.37 mg g^-1, suggesting a homogeneous mode of sorption for quercetin.

Extraction and Determination of Quercetin from Ginkgo biloba by DESs-Based Polymer Monolithic Cartridge

Deep eutectic solvents (DES) were formed from choline chloride (ChCl). DES-modified polymer monolithic (DES-M), template molecular polymer monolithic and non-DES-M without a molecular template were synthesized in identical process. These polymer materials were characterized by field emission scanning electron microscopy and Fourier transform infrared spectroscopy. The significant selective adsorption properties of the polymers were assessed by an absorption capacity experiment and solid-phase extraction (SPE). The optimized extraction procedure was as follows: ultrasonic time (30 min), optimal solvent (ethanol) and liquid to material ratio (20 mL g-1). Under this condition, the amount of quercetin extracted from Ginkgo biloba was 290.8 mg g-1. The purification of G. biloba was achieved by the SPE process. Based on the results, DESs-based monolithic cartridges can be used for simple and efficient extraction and as a pre-concentration technique for the purification of bioactive compounds or drugs in aqueous environments with high affinity and selectivity.

Simultaneous determination of quercetin and its metabolites in rat plasma by using ultra-high performance liquid chromatography tandem mass spectrometry

Fast, selective, and sensitive ultra-high performance liquid chromatography method with tandem mass spectrometry detection for the determination of quercetin and its metabolites with various physico-chemical properties such as molecular weight, lipophilicity, and acid-base properties has been developed. These compounds included small hydrophilic phenolic acids and more lipophilic metabolites with preserved flavonoid structure in small amount of rat plasma. The developed method enables selective separation of phenolic acids and a pair of isomers tamarixetin and isorhamnetin with satisfactory peak shapes and a high sensitivity using mass spectrometry detection. In addition, two sample preparation procedures including protein precipitation and microextraction in packed sorbent (MEPS) were optimized. The sample acidification included in protein precipitation as well as optimizing of MEPS sorbents and elution solvents improved isolation of quercetin and related compounds from rat plasma. Finally, both methods developed for sample preparation were fully validated to demonstrate sufficient accuracy and precision and acceptable matrix effects. Both sample preparation approaches combined with mass spectrometry-based quantification allowed the simultaneous determination of quercetin and its metabolites from a small amount of biological samples of only 50 μL. Due to the fast and non-selective parallel sample preparation, the protein precipitation was eventually applied to plasma samples derived from pharmacokinetic studies.

Development of an eco-friendly approach based on dispersive liquid–liquid microextraction for the quantitative determination of quercetin inNasturtium officinale,Apium graveolens,Spinacia oleracea,Brassica oleracea var. sabellica, and food samples

A fast, sensitive, inexpensive and environment-friendly dispersive liquid–liquid microextraction technique was developed based on solidification of floating organic drops.

Simple and selective detection of quercetin in extracts of plants and food samples by dispersive-micro-solid phase extraction based on core–shell magnetic molecularly imprinted polymers

In the present study, a D-μ-SPE clean-up method was established for the analysis of quercetin in extracts of plants and food samples using a magnetic molecularly imprinted polymer as the sorbent by HPLC-UV detection.

Determination of selective serotonin reuptake inhibitors in biological samples via magnetic stirring-assisted dispersive liquid–liquid microextraction followed by high performance liquid chromatography

This work reports an efficient, quick and low-cost procedure for the determination of serotonin reuptake inhibitors (SSRIs) in low concentration levels in biological fluids.

Dispersive liquid-liquid microextraction: trends in the analysis of biological samples

Dispersive liquid-liquid microextraction (DLLME) is a recent microextraction technique that was first developed by Rezaee and co-workers in 2006. It allows the simultaneous extraction and preconcentration of analytes into a micro-volume of extracting solvent based on a ternary solvent system involving an aqueous phase, a nonpolar water immiscible high-density solvent that acts as extraction phase, and a disperser solvent, which is often polar and water miscible. This article presents an overview of DLLME applications in the analysis of biological samples (e.g., plasma and urine). Aside from the classical DLLME applications using high density extraction solvents, recent advances in the use of low density solvents and ionic liquids are also discussed. Although most of the applications deal with the analysis of organic target compounds, a few applications on the bioanalysis of inorganic substances are also included.

Separation/preconcentration and determination of quercetin in food samples by dispersive liquid-liquid microextraction based on solidification of floating organic drop -flow injection spectrophotometry

A new dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFOD)-flow injection spectrophotometry (FI) method for the separation and preconcentration of trace amounts of quercetin was developed. 1-Undecanol and methanol was used as the extraction and disperser solvent, respectively. The factors influencing the extraction by DLLME-SFOD such as the volume of the extraction and disperser solvents, pH and concentration of salt were optimized. The optimal conditions were found to be; volume of the extraction solvent, 80 μL; the volume of the disperser solvent, 100 μL; and the pH of the sample, 3. The linear dynamic range and detection limit were 5.0 × 10(-8)-5.0 × 10(-7) mol L(-1) and 1 × 10(-8) mol L(-1), respectively. The relative standard deviation (R.S.D.) at 6.1 × 10(-8) mol L(-1) level of quercetin (n = 10) was found to be 2.8 %. The method was successfully applied to the determination of quercetin in the apple, grape, onion and tomato samples. Figureᅟ

Dispersive liquid-liquid microextraction for the determination of flavonoid aglycone compounds in honey using liquid chromatography with diode array detection and time-of-flight mass spectrometry

A rapid approach for the determination of eight flavonoid aglycone compounds, baicalein, hesperitin, fisetin, naringenin, chrysin, myricetin, quercetin and kaempferol, in honey samples and related products has been optimized and validated. The enriched extracts obtained by dispersive liquid-liquid microextraction (DLLME) were analyzed by liquid chromatography with diode array detection coupled to electrospray ionization and time-of-flight mass spectrometry (LC-DAD-ESI-ToFMS). For DLLME, using acetonitrile and chloroform as disperser and extractant solvents, respectively, a Taguchi experimental method was applied to find the optimal combination of following six factors: disperser and extractant solvent volumes, sodium chloride concentration, pH of the aqueous phase, honey mass and centrifugation time. The sedimented organic phase obtained after centrifugation was evaporated, reconstituted in acetonitrile and submitted to LC. The matrix effect was evaluated, and it was concluded that sample quantification can be carried out against aqueous external standards when using DAD and by matrix-matched calibration in the case of ToFMS. Detection limits in the ranges of 0.4-4 and 0.01-0.5 ng g(-1) were obtained for DAD and ToFMS, respectively. Satisfactory recovery values between 80 and 111% were obtained for three spiked samples. Honeys and related products were analyzed and flavonoids were found within a wide range.