A dispersive liquid–liquid microextraction method based on solidification of floating organic droplet for determination of antiviral agents in environmental water using HPLC/UV

Ionic liquid-based dispersive liquid-liquid microextraction of succinic acid from aqueous streams: COSMO-RS screening and experimental verification

In the present investigation, a total of 108 combinations of ionic liquids (ILs) were screened using the conductor-like screening model for real solvents (COSMO-RS) with the aid of six cations and eighteen anions for the extraction of succinic acid (SA) from aqueous streams through dispersive liquid-liquid microextraction (DLLME). Using the screened ILs, an ionic liquid-based DLLME (IL-DLLME) was developed to extract SA and the role of different reaction parameters in the effectiveness of IL-DLLME approach was investigated. COSMO-RS results suggested that, quaternary ammonium and choline cations form effective IL combinations with [OH¯], [F¯], and [SO42¯] anions due to hydrogen bonding. In view of these results, one of the screened ILs, tetramethylammonium hydroxide [TMAm][OH] was chosen as the extractant in IL-DLLME process and acetonitrile was adopted as the dispersive solvent. The highest SA removal efficiency of 97.8% was achieved using 25 μL of IL [TMAm][OH] as a carrier and 500 μL of acetonitrile as dispersive solvent. The highest amount of SA was extracted with a stir time of 20 min at 300 rpm, followed by centrifugation for 5 min at 4500 rpm. Overall, the findings showed that IL-DLLME is efficient in extracting succinic acid from aqueous environments while adhering to the first-order kinetics.

Carbonized aerogel/ZnO-based dispersive solid phase extraction of daclatasvir and sofosbuvir from biological samples prior to liquid chromatography-tandem mass spectrometry

Daclatasvir and sofosbuvir are antiviral medications utilized in the treatment of chronic hepatitis C virus (HCV) infection. Due to their low therapeutic index, careful monitoring is necessary to ensure that the optimal dose is administered. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) is an exceptionally sensitive and specific technique for quantifying these drugs within biological matrices. In this study, we developed a novel dispersive solid-phase extraction method employing a carbonized bio aerogel composite with ZnO for efficient extraction of daclatasvir and sofosbuvir from exhaled breath condensate, urine, and plasma samples. The extracted analytes were subsequently subjected to analysis using HPLC-MS/MS. Optimal parameters including pH adjustment, sorbent quantity variation, and elution solvent selection were fine-tuned to achieve maximum recovery efficiency while ensuring selectivity enhancements. The developed method demonstrated broad linearity ranging between 1.2 and 200 ng/mL along with good precision (relative standard deviations ≤6.2 %) and an acceptable coefficient of determination (r2 ≥0.994). These findings establish our proposed method as suitable for reliable drug quantification in clinical 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.

A tool to assess analytical sample preparation procedures: Sample preparation metric of sustainability

Sample preparation is a key step in most analytical methods, generally regarded as the least green step of the entire procedure. The existing green metrics assess the greenness of sample preparation techniques through the evaluation of the whole analytical procedure: including sampling, sample preparation, and the final detection/quantitation. Such inclusion of the entire method makes assessing the sustainability of a newly developed sample preparation technique quite challenging, as many aspects not solely linked to the sample preparation step are unavoidably considered. Thus, an alternative metric that can explicitly and exclusively evaluate the sample preparation is proposed. The metric is simple; it reports the result with a clock-like diagram, displaying the greenness outcome of main sample preparation parameters and a total score. This new metric can differentiate closely related microextraction approaches in terms of sustainability. The metric is also open-source and can be used by downloading the Excel sheet provided.

Electrochemical sensor based on bio-inspired molecularly imprinted polymer for sofosbuvir detection

The electropolymerized molecularly imprinted polymers (MIP) have enabled the utilization of various functional monomers with superior selective recognition of the target analyte template. Methyldopa is an attractive synthetic dopamine analogue which has phenolic, carboxylic, and aminic functional groups. In this research, methyldopa was exploited to fabricate selective MIPs, for the detection of sofosbuvir (SFB), by a simple electropolymerization step onto a disposable pencil graphite electrode (PGE) substrate. The interaction between methyldopa, as a functional monomer, and a template has been investigated experimentally by UV spectroscopy. A polymethyldopa (PMD) polymer was electrografted onto PGE in the presence of SFB as a template. X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (ESI), and cyclic voltammetry (CV) were used for the characterization of the fabricated sensor. Differential pulse voltammetry (DPV) of a ferrocyanide/ferricyanide redox probe was employed to indirectly detect the SFB binding to the MIP cavities. The sensor shows a reproducible and linear response over a dynamic linear range from 1.0 × 10-11 M to 1.0 × 10-13 M of SFB with a limit of detection of 3.1 × 10-14 M. The sensor showed high selectivity for the target drug over structurally similar and co-administered interfering drugs, and this enabled its application to detect SFB in its pharmaceutical dosage form and in spiked human plasma samples.

An environment-friendly approach using deep eutectic solvent combined with liquid-liquid microextraction based on solidification of floating organic droplets for simultaneous determination of preservatives in beverages

With the increase in environmental protection awareness, the development of strategies to reduce the use of organic solvent used during the extraction process has attracted wide attention. A simple and green ultrasound-assisted deep eutectic solvent extraction combined with liquid-liquid microextraction based on solidification of floating organic droplets method was developed and validated for the simultaneous determination of five preservatives (methyl paraben, ethyl paraben, propyl paraben, isopropyl paraben, isobutyl paraben) in beverages. Extraction conditions including the volume of DES, value of pH, and concentration of salt were statistically optimized through response surface methodology using a Box-Behnken design. Complex Green Analytical Procedure Index (ComplexGAPI) was successfully used to estimate the greenness of the developed method and compare with the previous methods. As a result, the established method was linear, precise, and accurate over the range of 0.5-20 μg mL^-1. Limits of detection and limits of quantification were in the range of 0.15-0.20 μg mL^-1 and 0.40-0.45 μg mL^-1, respectively. The recoveries of all five preservatives ranged from 85.96% to 110.25%, with relative standard deviation less than 6.88% (intra-day) and 4.93% (inter-day). The greenness of the present method is significantly better compared with the previous reported methods. Additionally, the proposed method was successfully applied to analysis of preservatives in beverages and is a potentially promising technique for drink matrices.