High-performance Liquid Chromatography-ultraviolet Detection Research Articles

Preconcentration of Cinnamic Acid Derivatives in Traditional Chinese Medicines by an Effective Dispersive Liquid-Liquid Microextraction Based on a Hydrophobic Deep Eutectic Solvent.

A dispersive liquid-liquid microextraction based on hydrophobic deep eutectic solvent (hDES) was developed for the extraction and quantification of four cinnamic acid derivatives in traditional Chinese medicines coupled with high-performance liquid chromatography-ultraviolet detection. In this method, a hDES (tetrabutylammonium chloride-hexanoic acid, molar ratio of 1:2) was prepared as the extractant. It only took 15 s to handle multiple samples simultaneously by hand-assisted dispersion. The use of a narrow-bore tube reduced the amount of the hydrophobic extractant with easier recovery. The approach was influenced by several key parameters, including the composition and consumption of the DES, sample phase pH, salt amount, extraction time, and centrifugation time, all of which had been investigated and optimized. Moreover, the formation of the DES was characterized by Fourier-transform infrared spectroscopy and differential scanning calorimetry. Under the optimal conditions, enrichment factors of the target analytes ranged from 135 to 220. Satisfactory linearities (r ≥ 0.9977), detection limits (0.2-0.4ng/mL), precision (<8.5%), and accuracy (recoveries: 90.0%-104.6%) were obtained. The method has been successfully applied to the simultaneous extraction and preconcentration of four cinnamic acid derivatives in Chinese medicinal samples with rapidness, high efficiency, and convenience.

A Polyacrylate Cotton-based Pipette Tip Micro-solid-phase Extraction Technique Coupled with High-performance Liquid Chromatography for Carvedilol Determination in Aqueous Media

Introduction: In this work, a polyacrylate polymer was synthesized into a pipette tip containing cotton fibers and used to extract carvedilol from water and urine samples. Methods: A high-performance liquid chromatography-ultraviolet detection method was developed, which demonstrated the suitability of the purposed pipette tip micro-solid-phase extraction device. Factors affecting the fabrication procedure and polymer quality were studied and optimized. In the next step, the sample preparation process (including extraction and desorption) was fully optimized, and the optimized method was validated. Results: A coating with suitable mechanical and chemical stability was achieved. Its structure was successfully characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Within-batch and between-batch fabrication reproducibility were obtained at 3.0 and 9.0 %, respectively. The developed method displayed a limit of detection of 1.1 µg L-1 when 1.5 mL of sample was processed, and it was linear in the concentration range of 3.3-350 µg L-1 with LLOQ of 5 µg L-1 . The polyacrylate cotton-based pipette tip was finally used to extract carvedilol from aqueous media with acceptable recoveries of 92-106%. Conclusion: The proposed method is simple and fast and requires low sample volumes. In addition, this method has been evaluated in terms of greenness with three different tools, and the evaluation results with all three tools have shown that this method is one of the green and environmentally friendly methods.

Preparation and evaluation of Fe3O4@C@NiCo-LDH@CDs composites for magnetic solid-phase extraction of trace endocrine disruptors.

The widespread use of endocrine disruptors (EDPs) has certain potential hazards to organisms and environments, and it is particularly important to develop effective pretreatment methods before detection of EDPs in complex samples. In this work, a novel magnetic nanocomposite decorated with layered double hydroxides (LDHs) and carbon dots (CDs) was designed and prepared for magnetic solid-phase extraction (MSPE) of EDPs (bisphenol S, bisphenol F, bisphenol A, bisphenol AF, diethylstilbestrol and 4-cumylphenol) combined with high-performance liquid chromatography-ultraviolet (HPLC-UV) detection. The prepared composites were characterized by field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS), and the adsorption mechanism towards these EDPs might be mainly based on hydrogen bonds and π-π conjugation. Under the optimized conditions, the proposed method showed limits of detection within 0.05-0.50 μg L-1 and limits of quantitation within 0.2-2.0 μg L-1, and good linearity (R2 ≥ 0.9975) was presented in the range of 0.2-200 μg L-1. Finally, the Fe3O4@C@NiCo-LDH@CDs composite-based MSPE-HPLC-UV method was applied for enrichment and determination of EDPs in water, milk, and tea beverage samples with recoveries in the range of 81.2-119.8% and relative standard deviations below 9.7%.

Extraction and detection of sulfonamide antibiotics in milk using magnetic solid-phase adsorbent based on molecular mechanics and DFT calculations

Based on the foundation of calculations in molecular mechanics and density functional theory (DFT) for in-depth mechanistic studies, this paper proposes the sample multi-residue analysis method of five common sulfonamide antibiotics (SAs) in milk. Fe3O4 nanoparticles modified magnetic graphene oxide nanoribbons (Mag-GONRs) with superior dispersibility and dispersion stability, were developed and firstly utilized to rapidly extract residual SAs from milk. Therefore, various SAs in complex samples could be simultaneously determined solely by high performance liquid chromatography-ultraviolet detector (HPLC-UV) without the need for complicated pretreatment processes. In order to obtain satisfactory extraction efficiency, indispensable investigation and optimization were conducted on some parameters influencing the extraction efficiency. And the extracted SAs were determined by. Good linearity for all analytes was achieved with appropriate correlation coefficients (R2 higher than 0.9978). The limits of detection ranged from 0.060 to 0.075 ng·mL−1. Recoveries of the sulfonamides in spiked milk samples were between 79.6 % and 114.6 %, with relative standard deviations within 12 %. Interestingly, with the assistant of computational chemistry, the efficient extraction of Mag-GONRs onto SAs has been validated at the molecular and quantum levels, further elucidating the adsorption mechanism based on non-covalent interactions. In the context of theoretical research and experimental results mutually supporting each other, a practical detection method with actual application value has been proposed in monitoring the residual sulfonamides in milk by the common devices.

In-tube solid-phase microextraction of polycyclic aromatic hydrocarbons from refinery water samples using UiO-66/polyacrylonitrile electrospun nanofibers followed by high-performance liquid chromatography-ultraviolet detection.

A simple and quick fiber-in-tube solid-phase microextraction (FIT-SPME) was introduced for the extraction and determination of nine polycyclic aromatic hydrocarbons followed by a high-performance liquid chromatography-ultraviolet detector in refinery water samples. For this purpose, a water-resistant metal-organic framework with a high surface area called UiO-66 has been applied in the form of an electrospun coating on stainless steel wires. After that, all the fibers were packed in the lumen of a stainless-steel tube to make the extraction phase. Both one variable at a time and experimental design methods have been used to optimize effective parameters on FIT-SPME. Under optimum conditions, the method demonstrated good linearity between 0.5 and 1000.0µg/L with a coefficient of determination greater than 0.9906. Furthermore, the limits of detection values ranged from 0.2 to 1.5µg/L. The intra-day and inter-day relative standard deviations were<8.4% and<9.7%, respectively. Lastly, the proposed method was applied to extract and determine analytes in four refinery water samples as well as surface water containing high total dissolved solids, and well waters where satisfactory results have been obtained.

Determination of anamorelin concentration in human plasma using a simple high-performance liquid chromatography-ultraviolet detection method.

Anamorelin, a non-peptide ghrelin analog and growth hormone secretagogue, is a novel oral drug used to treat cancer cachexia. Patients with cancer cachexia frequently use several drugs and anamorelin is a substrate of cytochrome P450 (CYP) 3A4; therefore, drug-drug interactions with CYP3A4 inhibitors and inducers pose a clinical problem. In this study, we aimed to determine the concentration of anamorelin in human plasma using a simple high-performance liquid chromatography-ultraviolet (HPLC-UV)-based method. The analysis involved extracting a 200-μL plasma sample and protein precipitation using solid-phase extraction. Anamorelin was isocratically separated using a mobile phase consisting of 0.5% potassium dihydrogen phosphate (pH 4.5) and acetonitrile (61:39, v/v) on a Capcell Pack C18 MG II column (250 mm × 4.6 mm) at a flow rate of 1.0 mL/min and monitored at a detection wavelength of 220 nm. The calibration curve was linear within a plasma concentration range of 12.5-1,500 ng/mL, with a coefficient of determination of 0.9999. The intra- and inter-day coefficients of variation were 0.37-6.71% and 2.05-4.77%, respectively. The accuracy of the assay and recovery were 85.25-112.94% and > 86.58%, respectively. This proposed HPLC-UV method is simple and can be applied in clinical settings.

External surface hydrophilic 3D-POSS-COF@GDL for the direct adsorption of bisphenols in milk samples

In case of organic frameworks (COFs) as adsorbents in the pretreatment of complex food matrices, challenges such as poor dispersion and non-specific adsorption of interfering macromolecules like proteins are often encountered. To address this issue, this work prepared a three-dimensional covalent organic framework (3D-COF) with a novel bcu topology based on polyhedral oligomeric silsesquioxane (POSS). Subsequently, gluconolactone (GDL) was modified onto the external surface of the material via the reaction with the exposed reactive residues. The resulting POSS-COF@GDL adsorbent has an enhanced hydrophilicity in the external surface, thereby significantly improves the dispersion of materials in aqueous solution and reduces the adsorption ability toward protein. Whereas, the inner of material retains hydrophobic pores that exhibit high adsorption efficiency to small hydrophobic molecules. Compared with the traditional pretreatment methods, POSS-COF@GDL can directly extract bisphenols (BPs) in milk samples without any additional treatment. The established sample pretreatment method is coupled with high-performance liquid chromatography-ultraviolet detection (HPLC-UV), resulting in recoveries of 71.8 to 93.6%, intra- and inter-day relative standard deviations (RSDs) of <8.3%, and limits of detection (LODs) of 0.042–0.16 ng∙mL−1 for four BPs.

Hydroxyl-functionalized cationic porous organic polymers for efficient enrichment and detection of phenolic endocrine disrupting chemicals in water and snapper

Endocrine-disrupting chemicals (EDCs) can disrupt the normal functioning of the endocrine system in organisms, leading to various health issues. Therefore, monitoring EDCs in the environment and food is of significant importance. In this study, a hydroxyl-functionalized ionic porous organic polymer (OH-IPOP) has been synthesized for the first time using 2-benzimidazolemethanol as a monomer. The OH-IPOP exhibited excellent adsorption performance towards phenolic EDCs. An efficient method for determination of phenolic EDCs (p-tert-butylphenol, bisphenol B, bisphenol A and bisphenol F) in environmental water and snapper samples was successfully established by with OH-IPOP as solid-phase extraction sorbent and determination with high-performance liquid chromatography-ultraviolet detection. The method showed good linearity (r2 > 0.998), low detection limits (0.008–0.020 ng mL−1 for lake water, 1.00–3.00 ng/g for snapper), high recovery rates (82.3–106 %), and good precision (relative standard deviation < 6.6 %), making it a highly efficient adsorbent for the enrichment of EDCs in complex sample matrices.

A green liquid phase microextraction using phthalic acid as switchable hydrophilicity solvent for the HPLC determination of sildenafil (Viagra®) in human urine

Herein, a green liquid phase microextraction protocol using phthalic acid as switchable hydrophilicity solvent (SHS) is reported for the quantification of sildenafil in authentic human urine. The analyte was extracted onto phthalic acid solid particles which were produced through acidification of the sample. Its solidification was accomplished at ambient conditions without sample cooling. The determination of the sildenafil was carried out using high performance liquid chromatography-ultraviolet detection (HPLC-UV). The microextraction parameters that affect the extraction efficiency of the drug (i.e. SHS type and its concentration, acid type and concentration, extraction time, filter type) have been studied. The optimized analytical protocol involved the mixing of 300 μL of phthalate solution (0.75 M) with 600 μL of sample, followed by the addition of 50 μL of concentrated H3PO4. The produced solid was collected using membrane syringe filter (0.45 μm) and was finally dissolved in 500 μL of CH3OH. Method validation data showed determination coefficient ≥ 0.99 for the linear range of 50 – 2000 ng/mL. The limit of detection (LOD) and the lower limit of quantitation (LLOQ) were 30 and 100 ng/mL, respectively. The accuracy (expressed as % recovery) of the method ranged between 88.0 – 108.9 % while the precision (expressed as % RSD) was less than 17.8 % in all cases. The robustness of the microextraction procedure and the instrumental method were investigated using Plackett-Burman experimental designs. The applicability of the method was demonstrated by analyzing both spiked and authentic human urine samples after oral administration of drug-containing pharmaceutical formulation. The developed protocol offers cost-efficiency, handling simplicity, and high throughput. Its green character was evaluated using Green Analytical Procedure Index and Blue Applicability Grade Index.

A Cost-Effective and Sensitive Method for the Determination of Lincomycin in Foods of Animal Origin Using High-Performance Liquid Chromatography.

Lincomycin (LIN) is extensively used for treating diseases in livestock and promoting growth in food animal farming, and it is frequently found in both the environment and in food products. Currently, most of the methods for detecting lincomycin either lack sensitivity and precision or require the use of costly equipment such as mass spectrometers. In this study, we developed a reliable high-performance liquid chromatography-ultraviolet detection (HPLC-UVD) method and used it to detect LIN residue in 11 types of matrices (pig liver and muscle; chicken kidney and liver; cow fat, liver and milk; goat muscle, liver and milk; and eggs) for the first time. The tissue homogenates and liquid samples were extracted via liquid-liquid extraction, and subsequently purified and enriched via sorbent and solid phase extraction (SPE). After nitrogen drying, the products were derivatized with p-toluene sulfonyl isocyanic acid (PTSI) (100 µL) for 30 min at room temperature. Finally, the derivatized products were analyzed by HPLC at 227 nm. Under the optimized conditions, the method displayed impressive performance and demonstrated its reliability and practicability, with a limit of detection (LOD) and quantification (LOQ) of LIN in each matrix of 25-40 μg/kg and 40-60 μg/kg, respectively. The recovery ranged from 71.11% to 98.30%. The results showed that this method had great selectivity, high sensitivity, satisfactory recovery and cost-effectiveness-fulfilling the criteria in drug residue and actual detection requirements-and proved to have broad applicability in the field of detecting LIN in animal-derived foods.

Alien species water hyacinth realizes waste into treasure: The preparation of biomass sorbent to determine benzoylurea insecticides in tea products.

A fast and effective analytical method with biomass solid-phase microextraction sorbent combined with a high-performance liquid chromatography-ultraviolet detector was proposed for the determination of benzoylurea (BU) insecticides in tea products. The novel sorbent was prepared by activating and then carbonizing water hyacinth with a fast growth rate and low application value as raw material and showed a high specific surface area and multiple interactions with analytes, such as electrostatic action, hydrogen bonding, and π-π conjugation. After optimizing the three most important extraction parameters (pH [X1], sample loading rate [X2], and solution volume [X3]) by Box-Behnken design, the as-established analytical method showed good extraction performance: excellent recovery (80.13%-106.66%) and wide linear range (1-400µg/L) with a determination coefficient of 0.9992-0.9999, a low limit of detection of 0.02-0.1µg/L and the satisfactory practical application results in tea products. All these indicate that the water hyacinth-derived material has the potential as a solid-phase extraction sorbent for the detection and removal of BU insecticides from tea products, and at the same time, it can also achieve the effect of rational use of biological resources, maintaining ecological balance, turning waste into treasure, and achieving industrial production.

Fabrication of magnetic hydrophilic imprinted polymers via two-step immobilization approach for targeted detecting bisphenol A

Molecularly imprinted polymer with water-compatibility for effective separation and enrichment of targeted trace pollutants from complicated matrix has captured extensive attention in terms of their high selectivity and matrix compatibility. This study focuses on modified β-cyclodextrin is used as a hydrophilic functional monomer to develop magnetic molecularly imprinted polymers (MMIPs). MMIPs were prepared using Fe3O4 nanoparticles as carriers and bisphenol A (BPA) as templates using a two-step fixation strategy and surface imprinting technology. The structural characteristic and binding properties of the prepared MMIPs were thoroughly studied. The MMIPs exhibited high crystallinity, high adsorption capacity, fast rebinding rate, remarkable selectivity and distinguish reusability. In addition, through magnetic solid-phase extraction separation technology and high-performance liquid chromatography ultraviolet quantitative detection technology, MMIPs are used for selective enrichment and detection of BPA in complex media such as environmental water and milk. This work provides a new route to construct the hydrophilic molecularly imprinted materials and a new sight on developing more effective sample pretreatment strategies for monitoring targeted pollution in complicated aqueous media.

Pompon mum-like ionic covalent organic framework nanocomposites for efficient solid-phase extraction of nonsteroidal anti-inflammatory drugs

Molecularly imprinted ionic covalent organic framework nanocomposites (MI-IC-COF@SnO2) were prepared as potential adsorbents for the enhanced adsorption of nonsteroidal anti-inflammatory drugs (NSAIDs) from aqueous solution. The resulting material exhibited a pompon mum-like structure, featuring a large surface area, and well-defined mesopores. The presence of uniform positive ions within the three-dimensional skeleton of MI-IC-COF@SnO2 facilitated a rapid adsorption rate and high adsorption capacity for target analytes. Thermodynamic fitting revealed the adsorption process of NSAIDs to be feasible, endothermic, and spontaneous. Additionally, the adsorbent material exhibited respectable selectivity, as evidenced by imprinting factor values ranging from 2.8 to 6.7. Utilizing MI-IC-COF@SnO2 as the sorbent, a solid-phase extraction method coupled with high-performance liquid chromatography-ultraviolet detection (SPE-HPLC-UV) was developed and optimized. The proposed method demonstrated good linear range with determination coefficients of 0.998–0.999, and low limit of detection (0.18–1.35 µg L−1). Recoveries of NSAIDs in urine and river water samples were 78.1 %–106.1 %, with relative standard deviations lower than 12.5 %. This rapid and sensitive method enables the determination of NSAIDs at trace levels in complex matrices, providing reliable and reproducible results.

Porphyrin Aluminum Metal-Organic Framework in Liquid Water, its Interaction with the Oxidized Organosulfur Compound Diethyl Sulfoxide, and its Sorption from Aqueous Solution.

Oxidized organosulfur compounds and, in particular, sulfoxides are of interest as solvents in the semiconductor and pharmaceutical industry, environmental contaminants, and simulants in deactivation of chemical warfare agents. An experimental study is reported of the interaction of porphyrin aluminum metal-organic framework Al-MOF-TCPPH2 (Compound 2) with diethyl sulfoxide (DESO) in pure form and in aqueous solution. First, the suitability of Compound 2 as sorbent in aqueous solution was assessed; namely, its long-term stability (up to 15 days) in liquid water has been investigated at room temperature and under stirring. Here, a novel facile spectroscopic method has been used, a periodic micro-sampling of sorbent from suspension, followed by vacuum mini-filtration and an ex situ time-dependent attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) analysis. Next, the interaction of Compound 2 with pure liquid DESO under ambient conditions was investigated, which yields the stoichiometric adsorption complex (Al-MOF-TCPPH2)1(DESO)2 denoted Compound 3. In this adsorption complex, molecules of DESO interact with the OH group and carboxylate group of the sorbent. Then, the removal of DESO from Compound 3 was assessed, using facile treatment with warm water in the micro Soxhlet apparatus followed by the ATR FT-IR analysis. Finally, Compound 2 was tested in sorption of DESO from diluted aqueous solution. In the initial step, the sorption proceeds very quickly (in <1 min the concentration of DESO decreases by about 20%) followed by a much slower step. The maximum amount of adsorbed DESO corresponds to half of the amount adsorbed from pure DESO as found by the high-performance liquid chromatography-ultraviolet detection method. This adsorbed amount corresponds to 1 mol DESO adsorbate per mol of sorbent. Porphyrin aluminum metal-organic framework Compound 2 is promising for the removal of DESO from diluted aqueous solution, and it is of interest for the removal of similar oxidized organosulfur compounds.

Study on determination methods and analysis of micronutrients in take-away meals

To comprehensively analyze the trace nutrient contents in take-away meals, the simultaneous detection method of common vitamins in take-away meals were explored based on the samples&apos; matrix, and the content of trace nutrients in take-away meals was analyzed combined with inductively coupled plasma-mass spectrometry(ICP-MS) detection of common elements. Fifty-seven take-away meals were collected randomly and analyzed. Vitamins were determined by high performance liquid chromatography-ultraviolet detector tandem fluorescence detector after pretreatment of samples including enzymatic digestion, hydrolysis and extraction. The separation was performed on a C_(18) column(250 mm×4.6 mm, 5 μm) with ion-pair acid reagents as the mobile phase for water-soluble vitamins and methanol for fat-soluble vitamins. Vitamin B_1, vitamin B_2, nicotinic acid, nicotinamide and vitamin A were detected by ultraviolet detector(UVD), while vitamin B_6 and E by fluorescence detector(FLD). Elemental analysis of calcium, magnesium, sodium, potassium, zinc, selenium and copper in the take-away meals was carried out according to GB 5009.268-2016 by ICP-MS to comprehensively evaluate the contents of micronutrients. Through optimization of chromatography and sample pretreatment conditions, the sensitivity of the established detection method can meet the needs of micronutrient evaluation with the detection limits and quantification limits of vitamins in the range of 0.002-0.098 mg/100 g and 0.007-0.327 mg/100 g, respectively. Good precision was obtained(&lt;10%). The spiked recovery rates were 80.5%-103.8%(n=6). The result showed that the contents of micronutrients in take-away meals were generally low. The detection rates of vitamins ranged from 21.1% to 98.2%. The proposed method is simple and sensitive, and the contents of vitamins and elements determined were low in the collected take-away meals.

Development, optimization and validation of an analytical method for the determination of voriconazole in plasma by high-performance liquid chromatography-ultraviolet detection: Application for comprehensive study

Voriconazole is a widely used antifungal agent in clinical settings. However, its use has been associated with neurological side effects in some patients. For this reason, it is crucial to monitor its plasma levels to ensure that they are within the therapeutic range. Thus, in this study, we aimed to develop a simple, fast, and efficient method for the determination of voriconazole in plasma using reversed-phase HPLC-UV. We also aimed to validate the method for its application to routine analysis of immunocompromised patients. Plasma samples from immunocompromised patients were subjected to deproteinization with acetonitrile followed by centrifugation. Chromatographic separation was carried out on a C18 column with UV detection at 254nm in isocratic mode. The concentrations were calculated by comparing peak areas to those of the internal standard, ketoconazole. The method was validated using the accuracy profile, which uses a calibration curve established for the therapeutic range of 1 to 5.5μg/mL. The developed method was proved to be rapid by giving a short analysis time for voriconazole at around 5.5min. Additionally, no interference with the biological matrix was detected. The obtained recoveries were higher than 90%. The accuracy profile showed that the method was accurate and precise for the determination of voriconazole in plasma. The developed method was proved to be simple, efficient, that requires minimal sample preparation. Thus, it can be routinely applied for the therapeutic monitoring of voriconazole.

Natural kapok fiber as a green and efficient adsorbent for in-syringe solid-phase extraction in the determination of antidepressants in biofluids

Effective antidepressant monitoring is crucial for safe treatment, with liquid chromatography being the primary detection method. Due to the complexity of biofluids, meticulous sample preparation is vital to remove interferences and concentrate analytes. In this study, a novel solid-phase extraction method utilizing unprocessed kapok fiber (KF) as an eco-friendly and efficient sorbent, ingeniously incorporated within an in-syringe device for the extraction of antidepressants from biofluids was introduced. The extraction process displayed several advantages, including simplicity and rapidity (less than 3 min with minimal manual intervention), as well as the potential for automation, which represents significant advancements in sample preparation techniques. The method demonstrated excellent analytical performance when coupled with high-performance liquid chromatography-ultraviolet detection, achieving good linearity (R2 ≥ 0.991), excellent relative recovery (92.6–107.5 %), high precision in intraday and interday analyses (RSDs within 0.8–6.0 % and 1.2–7.9 %, respectively), and good sensitivity with limits of quantification between 5–10 ng/mL. Notably, given the use of a renewable and biodegradable material with KF, and a low-toxicity desorption solvent with ethanol, the developed method stands out for its environmental sustainability, aligning with green analytical chemistry principles. Its application to real biological samples validates its efficacy as a rapid and reliable tool for clinical and forensic monitoring of antidepressants. Moreover, the low cost of this method facilitated by the economical nature of KF and the reusability of syringes further enhances its practicability. This study presents a unique approach by employing natural and renewable KF as adsorbents, thereby eliminating the need for complex material synthesis and making a pioneering contribution to the field of analytical chemistry for drug analysis in complex matrices.

Modification of cellulose substrate by in situ synthesis of metal-organic framework-5 for thin film microextraction of some non-steroidal anti-inflammatory drugs and their measurement by high-performance liquid chromatography-ultraviolet detector

This work, reports the successful preparation a thin film by a simple and inexpensive process for quantification of a model analytes in the urine sample using HPLC-UV. To this end, cellulose paper was employed as a substrate for the in-situ synthesis of MOF-5, to increase the resistance of the prepared film. The prepared film can be reused 26 times with no reduction in its performance. The thin film prepared by MOF-5 modified cellulose substrate was utilized in thin film microextraction (TFME) method for the extraction and preconcentration of naproxen, aspirin, tolmetin, and celecoxib. Under optimal conditions, the linear dynamic range of the target analytes was 2–500 µg L−1 with correlation coefficients (R2) ranging from 0.9961 to 0.9990. Also, the limits of detection (LODs), the limits of quantification (LOQs) and relative standard deviation (RSD%) of the proposed method for selected analytes ranged between 0.57 and 0.77 µg L−1, 1.7 to 2.3 and 3.5 % to 6.2 %, respectively. Moreover, relative recoveries varied from of 94 % to 108 %, indicating the absence of matrices effect in the proposed method. Eventually, the TFME was successfully used for the extraction of selected analytes from urine samples.

Combining EDTA-intercalated (Zn-Al) layered double hydroxides/graphite and two-phase hollow fiber for liquid phase microextraction of nonsteroidal anti-inflammatory drugs

This study synthesized and characterized layered double hydroxides (LDHs) intercalated with ethylenediaminetetraacetic acid(EDTA) to increase the basal spacing of electrosynthesized Zn-Al-LDHs on pencil graphite (PG). The characteristic verification of the Zn-Al-EDTA-LDH nanostructures was conducted utilizing Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive and X-ray analysis (EDS), and X-ray diffraction (XRD). To improve the extraction efficiency, Zn-Al-EDTA-LDHs as adsorbent in solid phase microextraction (SPME) fiber was combined with hollow fiber liquid–liquid phase microextraction (HF-LLPME) to investigate the extraction efficiency of HF-LLME@PG-SPME technique the chosen non-steroidal anti-inflammatory drugs (NSAIDs) from aqueous solution Several variables, comprising extraction time, desorption time, stirring rate, desorption volume, pH of donor phase, and salt effects were screened and optimized by performing placket-Burman design (PBD). After evaluating the extraction and desorption procedures under optimal conditions, NSAIDs analysis was performed employing high-performance liquid chromatography-ultraviolet detection (HPLC-UV). Compared to the most common clean-up and sample preparation methods, the current study focused on developing a greener analytical chemistry process due to reduced solvent consumption, cost-effectiveness, miniaturization and simplified design. The proposed method for NSAIDs exhibited a good linear dynamic range (LDRs) (1.00–200.00 µg/L) with a coefficient of determination of > 0.9956, low limits of detection (LODs) (0.26–0.29 µg/L) and acceptable limits of quantifications (LOQs) (0.86–0.96 µg/L). Relative standard deviations of 5.31 % could be determined. The absolute recoveries of the urine sample analyses could be obtained in a 89.91–97.61 % range and enrichment factors (EFs) (178.92 to 183.88). Investigations of the developed method were also conducted in various urine samples containing the selected drugs. As a result of the obtained recoveries, the method proved to be valuable and suitable to complicated biological samples.

Utilization of a pH-switchable hydrophilicity solvent for the microextraction of clomipramine from human urine samples

Clomipramine (CLP) is a tricyclic antidepressant drug, and its determination in biological samples is of high importance in clinical and forensic evaluations to assure appropriate drug concentrations. In the present study, benzoic acid was employed as a pH-switchable hydrophilicity solvent (SHS) for the microextraction of CLP from authentic human urine samples prior to its determination by high performance liquid chromatography-ultraviolet detection (HPLC-UV). The microextraction protocol was based on the phase transition of the SHS through pH alteration that resulted in its rapid dispersion and simultaneous phase separation. The obtained solid was collected in a syringe filter, dissolved in methanol, and analyzed. The main parameters that affected the efficiency of the microextraction procedure were studied and optimized to ensure high extraction efficiency for CLP and the analytical method was validated. Under optimum conditions, good linearity was observed between 0.05 and 5.0 μg mL−1. The limit of detection and limit of quantification were found to be 0.015 and 0.05 μg mL−1, respectively. The RSD values for intra-day repeatability and inter-day precision were 2.4–8.9 % and 1.7–9.1 %, respectively. The relative recovery values were within 90.0 and 110.0 % in all cases, demonstrating good method accuracy. The proposed SHS microextraction showed cost-efficiency, handling simplicity, and rapidity resulting in enhanced sample throughput. Moreover, the proposed method exhibited a green character and good applicability based on its evaluation by Green Analytical Procedure Index and Blue Applicability Grade Index.