High-performance Liquid Chromatography-ultraviolet Research Articles

Magnetic nanofluid based on green deep eutectic solvent for enrichment and determination of chloramphenicol in milk and chicken samples by high-performance liquid chromatography-ultraviolet: Optimization of microextraction

In this work, magnetic nanofluid based on a deep eutectic solvent that constricts through a simple and easy route, and subsequently applied for the preconcentration and microextraction of chloramphenicol (CAP) as a hazardous drug from milk and chicken samples via syringe-to-syringe microextraction prior to its determination by high-performance liquid chromatography–ultraviolet (HPLC-UV). In addition, the optimum conditions of effective factors were searched by the central composite design (CCD), and subsequently, at their optimum value, the figures of merit were evaluated. Also, the suggested method illustrated a low limit of detection (0.2 ng mL−1), a low limit of quantitation (0.67 ng mL−1), and a good linear range with an R2 of 0.996. The CAP relative recoveries in milk and chicken samples were 90.3%–95.1%, with relative standard deviations lower than 4.2%. The current enhancement technique is simple, easy, and rapid, which makes it suitable for quantification of CAP by HPLC-UV at trace levels in complicated materials with reliable and reproducible results.

Microextraction of melamine from dairy products by thymol-nonanoic acid deep eutectic solvent for high-performance liquid chromatography-ultraviolet determination

In this work, it was shown for the first time that deep eutectic solvents provide effective liquid-phase microextraction of melamine from dairy products. In accordance with the developed procedure, the milk sample is mixed with salt (sodium sulfate) to precipitate proteins and, after that, melamine is extracted into the phase of a hydrophobic eutectic solution based on thymol and nonanoic acid. After phase separation, the analyte is detected in the eutectic solvent phase. In the developed analytical procedure, a medium-chain fatty acid as a precursor of the extraction solvent promotes mass-transfer of melamine due to strong interactions between carboxyl and amino groups. The terpenoid as a precursor of the extraction solvent has a synergistic effect in melamine extraction due to possible π–π interaction. The estimated phenomenon was applied to the effective separation of highly hydrophilic analyte from aqueous sample phase followed by its determination by high-performance liquid chromatography. Under optimal conditions, a range of determined concentration was from 0.1 to 30 mg L−1 with a limit of detection of 0.03 mg L−1. The procedure is fast (7 min), miniaturized (100 μL of the extraction solvent) and repeatable (RSD % < 5 %). The developed procedure was optimized and used for the determination of melamine in real samples of powdered and whole milk.

Dissolution testing of ursodeoxycholic acid suspension using SPE as sample preparation

Abstract Objectives To develop and validate an analytical method by HPLC–UV (High Performance Liquid Chromatography–Ultraviolet) for the quantification of ursodeoxycholic acid suspension in a dissolution test followed by a solid phase extraction (SPE) to circumvent the interference of sodium lauryl sulphate (SLS) present in the dissolution medium. Methods United States Pharmacopeia (USP) apparatus 2. The dissolution medium was 900 ml of an aqueous solution of 0.05 M phosphate buffer (pH 8.4) with 2% SLS. The samples were filtered and cleaned by SPE with 500 mg/3ml C18 cartridges. The analytical method was validated for specificity, linearity, LOD (limit of detection), LOQ (limit of quantification) accuracy and precision. Chromatographic conditions, Symmetry-C18 column (150 mm × 4.6 mm, id; 5 µm particle size), 40°C, 100 µl injection volume and UV detection at 200 nm. The flow rate was 1 ml/min using acetonitrile–phosphoric acid (pH 3.0, 0.15 mM) (48:52). Key findings SPE provided an efficient and selective extraction of ursodeoxycholic acid from the dissolution medium. On the other hand, the SPE washing step allowed the elimination of SLS. The ursodeoxycholic acid method optimisation and validation were accomplished with no less than 80% in 30 min. Conclusion The developed analytical method was simple and adequate for the analysis of ursodeoxycholic acid suspension samples that met the USP specifications for dissolution test.

Trace determination of triazine herbicides in fruit and vegetables using novel hydrophobic deep eutectic solvent-based dispersive liquid-liquid microextraction followed by high-performance liquid chromatography-ultraviolet.

In the present research, a novel hydrophobic deep eutectic solvent-based dispersive liquid-liquid microextraction technique was established and combined with high-performance liquid chromatography-ultraviolet for the determination of triazine herbicides in fruit and vegetable samples. A deep eutectic solvent was synthesized using l-menthol as a hydrogen bond acceptor and ethylene glycol as a hydrogen bond donor and used as a green extractant. The characterization of deep eutectic solvent was investigated by Fourier-transform infrared, nuclear magnetic resonance, and thermogravimetric analysis. Under the optimum conditions, relative standard deviation values for intra-day and inter-day of the method based on seven replicate measurements of 50.0μg/kg of triazines were in the range of 2.8%-5.5% and 3.7%-7.2%, respectively. The calibration graphs were linear in the range of 3.0-500μg/kg and the limits of detection were in the range of 1.0-2.0μg/kg. The relative recoveries of different fruit and vegetable samples that have been spiked with two levels of target compounds were 91.5%-109.8%. The method has good linearity, sensitivity, accuracy, and precision. It is also environmentally friendly and was successfully used to determine the concentrations of triazines in fruit and vegetable samples.

Determination of thiram residues in fresh water using flow injection diperiodatonickelate(IV)-quinine chemiluminescence detection.

This study developed a simple flow injection (FI) method based on diperiodatonickelate(IV)-sulfuric acid reaction using chemiluminescence (CL) detection for the determination of thiram (THI) fungicide in fresh water using quinine as the sensitizer. The possible mechanism of the CL reaction was described using UV-Vis. absorption and CL spectra. Experimental variables were optimized by applying a univariate approach, and a linear calibration curve was obtained in the range of 1.0 × 10-3 -2.0mg L-1 (R2 = 0.9994, n = 9) with a limit of detection of 5.0 × 10-4 mg L-1 (S/N = 3) and an injection throughput of 200 h-1 . This approach was successfully applied to determine THI in fresh water by using solid-phase extraction and achieved a good recovery rate of 94%-110% with a relative standard deviation of 1.9%-3.7% (n = 4). The results obtained were compared with the reported FI-CL and high-performance liquid chromatography-ultraviolet methods, and the three methods did not differ significantly at the 95% confidence limit.

Therapeutic drug monitoring of levetiracetam: Method validation using high-performance liquid chromatography-ultraviolet detector technique and usefulness in patient care setting.

To develop and validate a modified HPLC-UV method for the estimation of serum levetiracetam levels and to assess the usefulness of serum levetiracetam estimation in epileptic patients. Modification of a previously existing HPLC-UV method was performed using liquid- liquid phase extraction and processing using reverse phase analytic HPLC-UV detector technique followed by method validation. Serum samples of patients attending our hospital's Therapeutic Drug Monitoring Outpatient Department services were analyzed for levetiracetam levels using the study method. Data of the past 6 years (2015-2020) were descriptively analyzed. The modified HPLC-UV method was validated as per ICH Q2 (R1) 2005 guidelines. Usefulness of levetiracetam estimation was assessed in 1383 patients (635 children, 683 adults, 40 elderly, and 25 pregnant women). Levetiracetam levels were within the therapeutic range (TR) in 520 children, 543 young adults, 35 elderly patients, and nine pregnant women. In 112 of 232 patients with low levetiracetam levels, poor compliance was elicited. Of 641 patients on polytherapy, 446 patients had levetiracetam values within TR, whereas 29 had values above and 166 patients had values less than TR. Sodium valproate, phenytoin sodium, and carbamazepine affected levetiracetam levels when given concomitantly. Levetiracetam dose was adjusted in 61 patients with abnormal levels for better clinical response. Good seizure control was noted in 913 (82.47%) patients whose levels were within TR, whereas 136 (58.62%) patients with low levels reported an increase in seizure frequency. The modified HPLC-UV method is simple, rapid, efficient, and reliable for assaying serum levetiracetam.

Efficient enrichment of pesticides from environmental water samples by cobalt-nickel double metal hydroxide nanocage/multiwalled carbon nanotube composites

建立高效、灵敏的农药分离、富集和检测方法具有重要意义。该实验采用一步法合成了钴基沸石咪唑骨架/多壁碳纳米管(ZIF-67/MWCNTs)复合物,并以该复合物为模板通过溶剂热法合成了钴镍笼状双金属氢氧化物/多壁碳纳米管(CoNi-LDH/MWCNTs)复合材料,将CoNi-LDH/MWCNTs用作固相微萃取(SPME)的纤维涂层富集环境水样中的6种农药,结合高效液相色谱(HPLC)测定了环境水样中的6种农药。通过扫描电镜、能谱分析、红外光谱、粉末X射线衍射和N2吸附/脱附对所制备的各种材料进行了表征。利用正交设计试验优化SPME的萃取条件,包括萃取温度、萃取时间、搅拌速率、解吸时间和盐浓度。在最优化的条件下,该方法具有较宽的线性范围(百菌清为0.015~200 μg/L,戊唑醇为0.140~200 μg/L,毒死蜱为0.250~200 μg/L,仲丁灵为0.077~200 μg/L,溴氰菊酯为1.445~200 μg/L,哒螨灵为0.964~200 μg/L)、较低的检出限(0.004~0.434 μg/L)和良好的重复性。单个纤维和不同批次纤维间的相对标准偏差(RSD)分别为0.5%~5.7%和0.5%~4.8%。在10.0 μg/L和50.0 μg/L 2个水平下的加标回收率为83.9%~108.2%, RSD< 5.3%。此外,与其他涂层纤维相比,CoNi-LDH/MWCNTs涂层对农药具有更高效的富集能力,这归因于它的高比表面积以及CoNi-LDH/MWCNTs涂层与目标分析物之间存在的π-π堆积作用、疏水作用、阳离子-π相互作用和氢键作用。该方法可以实现环境水样中农药残留的高选择性、高灵敏度及高准确性的分析测定。

Simultaneous Prediction, Determination, and Extraction of Four Polycyclic Aromatic Hydrocarbons in the Environment Using a UCON-NaH2PO4 Aqueous Two-Phase Extraction System Combined with High-Performance Liquid Chromatography-Ultraviolet Detection.

In this paper, a new aqueous two-phase extraction system(ATPES) consisting of UCON (poly(ethylene glycol-ran-propylene glycol) monobutyl ether)–NaH2PO4 was established, and four trace polycyclic aromatic hydrocarbons (PAHs: fluorene, anthracene, pyrene and phenanthrene) in water and soil were analyzed by high-performance liquid chromatography (HPLC)–ultraviolet detection. In the multi-factor experiment, the central composite design (CCD) was used to determine the optimum technological conditions. The final optimal conditions were as follows: the concentration of UCON was 0.45 g·mL−1, the concentration of NaH2PO4 was 3.5 mol·L−1, and the temperature was 30 °C. The recovery of the four targets was 98.91–99.84% with a relative standard deviation of 0.3–2.1%. Then UCON recycling and cyclic tests were designed in the experiment, and the results showed that the recovery of PAHs gradually increased in the three extractions because of the remaining PAHs in the salt phase of last extraction. The recovery of PAHs in the UCON recycling test was less than that in the extraction test due to the wastage of UCON. In addition, a two-phase aqueous extraction model was established based on the random forest (RF) model. The results obtained were compared with the experimental data, and the root mean square error (RMSE) was 0.0371–0.0514 and the correlation coefficient R2 was 96.20–98.53%, proving that the model is robust and reliable.

Fluorine-Functionalized Covalent-Organic-Framework-Coated Stir Bar for the Extraction of Benzoylurea Insecticides in Pear Juice and Beverage Followed by High-Performance Liquid Chromatography-Ultraviolet Detection.

A fluorinated covalent organic framework (COF), named F-COF, was fabricated via simple room-temperature synthesis. With the characteristics of rich fluorine atoms, hydrophobicity, and large conjugated structure, F-COF was evaluated for the extraction of five benzoylurea insecticides (BUs) containing fluorine atoms, benzene ring, and urea bridge. Specifically, F-COF-coated stir bars were prepared by physical adhesion and exhibited higher extraction recovery (73-93 versus 40-85%) toward BUs than commercial stir bars in a shorter extraction time (50 min versus 24 h). The adsorption behavior of BUs on F-COF was explored, and it was assumed that the halogen bond (O-F), hydrophobic interaction, electrostatic interaction, and π-π stacking contributed to the adsorption. On the basis of it, a method combining stir bar sorptive extraction with liquid chromatography-ultraviolet detector was developed for trace analysis of five BUs. Under the optimal conditions, the limits of detection for BUs were found to be 0.301-0.672 μg/L, with the linear range of 1.0/2.0-500 μg/L and relative standard deviations of <8.0% (c = 5 μg/L and n = 7). The accuracy of the proposed method was validated by the recovery test, and the recoveries of target BUs in spiked pear juice and pear beverage were 82.0-113 and 84.0-112%, respectively.

Inosine monophosphate dehydrogenase activity and mycophenolate pharmacokinetics in children with nephrotic syndrome treated with mycophenolate mofetil

Some studies have shown that the area under the concentration-time curve (AUC) of mycophenolic acid (MPA) should be higher for children with nephrotic syndrome (NS) than after renal transplantation. The pharmacodynamic aspect of MPA, the activity of inosine monophosphate dehydrogenase (IMPDH), has not been studied in children with NS. The study included 21 children (4-16 years old) with NS treated with mycophenolate mofetil. MPA and its glucuronide plasma concentrations were determined using validated high-performance liquid chromatography-ultraviolet (HPLC-UV). The separate HPLC-UV method was applied for IMPDH activity determination. The variability was expressed by the coefficient of variation (CV). IMPDH activity and MPA concentration (Ctrough ) before the morning dose amounted to 29.95 μmol s-1 mol-1 adenosine monophosphate (AMP) (range, 6.71-98.60 μmol s-1 mol-1 AMP) and 1.72 μg/mL (range, 0.39-4.34 μg/mL), respectively, whereas the area under the effect-time curve from 0 to 4h and MPA AUC0-4 were 130.36 μmol s-1 mol-1 AMP × h (range, 23.58-306.57 μmol s-1 mol-1 AMP × h) and 24.63 μg h/mL (range, 12.21-67.48 μg h/mL), respectively. IMPDH activity decreased concomitantly with MPA concentration increase, however, the variability of the pharmacodynamic parameters was greater than of the pharmacokinetics. The median degree of maximum IMPDH inhibition was 61%. MPA Ctrough and predicted AUC were lower than in our previous study. Only a few MPA pharmacokinetic parameters correlated with the pharmacodynamics. IMPDH activity did not correlate with the children's age and did not differ between boys and girls. MPA clearance was the highest in younger children (median, 10.54 L/m2 /h) and cholesterol correlated negatively with the children's age (r=-0.659, P=0.003). IMPDH minimum activity and the degree of maximum IMPDH inhibition were similar to those obtained in renal transplant recipients. IMPDH activity does not undergo developmental or gender-specific regulation in children with NS. MPA underexposure might be more frequent in younger children, especially with high cholesterol and triglycerides levels because of high MPA clearance.

Development of a double monitoring system for the determination of Cr(VI) in different water matrices by HPLC-UV and digital image-based colorimetric detection method with the help of a metal sieve-linked double syringe system in complexation.

This study reports a cheap, efficient, sensitive, and simple double monitoring analytical method for trace determination of Cr(VI), which is toxic and harmful even at very low concentrations. A metal sieve-linked double syringe (MSLDS) system was used to help the formation of chromium complex (Cr-diphenyl carbazide, DPC) subsequently determined by high-performance liquid chromatography-ultraviolet (HPLC-UV) and digital image-based colorimetry (DIC) systems. The metal complex was eluted through a Phenomenex-Aqua C18 with a mobile phase comprising of 50mM ammonium formate solution (pH 4.0):acetonitrile (78:22, v/v) and detected by the UV detector at the wavelength of 581nm. Under their optimum conditions, the HPLC-UV and DIC systems exhibited good linearity in ranges of 10-500µg L-1 and 100-1000µg L-1, respectively. The percent relative standard deviations (RSD%s) calculated for the lowest concentrations of both systems fell below 10%, and this confirmed good repeatability for replicate measurements. The accuracy of the proposed methods was evaluated by performing spike recovery experiments on wastewater, river water, and tap water samples. The calculated recovery results were in the range of 81.5-105.5% for HPLC-UV system and 93.8-111.1% for the DIC system. These results indicate that the proposed methods are suitable for routine Cr(VI) determination in terms of their rapidness, simplicity, good repeatability, and low cost.

Development of Phytocosmeceutical Microemulgel Containing Flaxseed Extract and Its In Vitro and In Vivo Characterization.

Antioxidants from natural sources are extensively attaining consideration to avert the skin from damage and aging caused by free radicals. Flaxseed (Linum usitatissimum L.), a natural therapeutic agent, was meant to be explored cosmeceutical by quantifying its potential phytoconstituents and to be incorporated into a microemulgel for topical use. Hydroalcoholic fractions (both methanolic and ethanolic; 80%) flaxseed extracts were subjected to phytochemical screening by quantifying total phenolic content (TPC), total flavonoid content (TFC), and high-performance liquid chromatography-ultraviolet (HPLC-UV), and for biological activities through 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, tyrosinase inhibition assay, and sun protection factor (SPF). Ethanolic fraction was selected for further study by TPC (18.75 mg gallic acid equivalent/g) and TFC (1.34 mg quercetin equivalent/g). HPLC-UV analysis showed the existence of benzoic, quercetin, caffeic, vanillic, p-coumaric, gallic, cinnamic, syringic, and sinapic acids. Biological activities showed 87.00%, 72.00%, and 21.75 values for DPPH assay, tyrosinase inhibition, and SPF assays, respectively. An oil-in-water (OW) microemulsion containing the flaxseed extract, with 99.20 nm Zeta size, −19.3 Zeta potential and 0.434 polydispersity index was developed and incorporated in Carbopol-940 gel matrix to formulate an active microemulgel with 59.15% release in in vitro studies. The successfully formulated stable active microemulgel produced statistically significant effects (p < 0.05), in comparison to a placebo, on skin erythema, melanin, sebum, moisture, and elasticity, in a noninvasive in vivo study performed on 13 healthy human female volunteers. Other cosmeceutical products can also be formulated from flaxseed, making it a considerable candidate for further utilization in the pharmaceutical industry.

Composition of aerosols from thermal degradation of flavors used in ENDS and tobacco products

Aim: The cardiovascular toxicity of unheated and heated flavorants and their products as commonly present in electronic cigarette liquids (e-liquids) was evaluated previously in vitro. Based on the results of in vitro assays, cinnamaldehyde, eugenol, menthol, and vanillin were selected to conduct a detailed chemical analysis of the aerosol generated following heating of each compound both at 250 and 750 °C. Materials and Methods: Each flavoring was heated in a drop-tube furnace within a quartz tube. The combustion atmosphere was captured using different methods to enable analysis of 308 formed compounds. Volatile organic compounds (VOCs) were captured with an evacuated Summa canister and assayed via gas chromatography interfaced with mass spectrometry (GC–MS). Carbonyls (aldehydes and ketones) were captured using a 2,4-dinitrophenylhydrazine (DNPH) cartridge and assayed via a high-performance liquid chromatography-ultra-violet (HPLC-UV) assay. Polyaromatic hydrocarbons (PAHs) were captured using an XAD cartridge and filter, and extracts were assayed using GC–MS/MS. Polar compounds were assayed after derivatization of the XAD/filter extracts and analyzed via GC–MS. Conclusion: At higher temperature, both cinnamaldehyde and menthol combustion significantly increased formaldehyde and acetaldehyde levels. At higher temperature, cinnamaldehyde, eugenol, and menthol resulted in increased benzene concentrations. At low temperature, all four compounds led to higher levels of benzoic acid. These data show that products of thermal degradation of common flavorant compounds vary by flavorant and by temperature and include a wide variety of harmful and potentially harmful constituents (HPHCs).

Characterization of Trans-Resveratrol in Peanut Oils Based on Solid-Phase Extraction with Loofah Sponge Combined with High-Performance Liquid Chromatography-Ultraviolet (HPLC–UV)

Characterization of Trans-Resveratrol in Peanut Oils Based on Solid-Phase Extraction with Loofah Sponge Combined with High-Performance Liquid Chromatography-Ultraviolet (HPLC–UV)

Assessment and Quantification of Homovanillic Acid and Vanillylmandelic Acid in Rodent Urine Samples Using a Validated High-Performance Liquid Chromatography-Ultraviolet Method

Objective: The purpose of this study was to establish a validated analytical method for estimating the biogenic amine metabolites vanillylmandelic acid (VMA) and homovanillic acid (HVA) simultaneously using the high-performance liquid chromatography-ultraviolet (HPLC-UV) method. Materials and Methods For the analysis of VMA and HVA in artificial urine samples, an HPLC method was devised and validated. The chromatographic separation was achieved on Kromasil C8, 5 μm (125 mm × 4.6 mm) column at an ambient temperature of 25°C, with mobile phase combination of acetonitrile: 0.1% orthophosphoric acid in ratio of 30:70 v/v at a flow rate 0.5 mL/min using Agilent HPLC system. For the separation of these two metabolites, different mobile phases were used on a trial and error basis. In terms of linearity, accuracy, repeatability, precision, and robustness, the developed technique was validated according to ICH guidelines. Results A high-resolution HPLC method was devised for the separation of VMA and HVA. VMA and HVA were found to be linear over the concentration range of 10 to 35 μg/mL, with coefficients of determination (r 2) of 0.955 and 0.963 for both metabolites, respectively. VMA and HVA had detection limits of 1.7 and 1.8 μg/mL, respectively, and quantification limits of 5.2 and 5.3 μg/mL. The results showed a low value of % relative standard deviation for repeatability, intra- and inter-day precision, and robustness studies. Conclusion A validated HPLC-UV method was developed for estimating VMA and HVA in urine samples.

Deep eutectic solvent-based ultrasound-assisted liquid–liquid microextraction of ibuprofen prior to HPLC-UV determination

ABSTRACT In this study, accurate and sensitive determination of ibuprofen in blood, urine, pharmaceutical tablet, syrup, and water samples was accomplished with the combination use of deep eutectic solvent-based ultrasound-assisted liquid–liquid microextraction (DES-UA-LLME) and high-performance liquid chromatography-ultraviolet visible detection system. The most important advantage of this method is that it can be used in the determination of ibuprofen without affecting the matrix environment of a wide range of samples. Ibuprofen in the sample phase was extracted to 500 µL of deep eutectic solvents phase (ChCl:Ph at 1:4 molar ratios) at pH 3.0. The influence of analytical parameters, such as pH of sample solution, the molar ratio of deep eutectic solvents components, tetrahydrofuran volume, and volume of DESs, were optimised in details. The preconcentration factor (PF), the detection limit (DL), intraday, and interday relative standard deviations (RSD, %) for the developed DES-UA-LLME/HPLC procedure were found as 30, 0.4 µg L−1, 1.74%, and 4.68%, respectively. The developed DES-UA-LLME was successfully used for the determination of ibuprofen in urine, blood, pharmaceutical tablet, syrup, and water samples.

Deep Eutectic Solvents and Layered Double Hydroxides in Solid‐Phase Extraction of Antidepressant Drugs

AbstractFor the first time, an acidic deep eutectic solvent (DES) comprised of malonic acid and ChCl was used to complete dissolution of Co‐Al, Ni‐Al, and Cu‐Al layered double hydroxides (LDHs) as sorbents in the vortex‐assisted in‐situ solid‐phase extraction of doxepin and amitriptyline followed by high‐performance liquid chromatography‐ultraviolet (HPLC‐UV). Moreover, the ability of urea:ChCl and ethylene glycol:ChCl was investigated to dissolve the LDH sorbents. The extraction conditions were optimized in terms of vortex time, molar ratio of Co2+:Al3+, NaOH concentration, and volume of DES based on the Box‐Behnen design. The linearity, limit of detection, and coefficient of determination R2 for both analytes were assessed as well. Recoveries of more than 93.1 % with relative standard deviations of less than 5.3 % were achieved for spiking urine and pharmaceutical formulation samples.

Introduction of a Zn-based metal\u2013organic framework @ biomass porous activated carbon as a high-sensitive coating for a stainless steel SPME fiber: application to the simultaneous analysis of nonsteroidal anti-inflammatory drugs

The present study introduces a high-efficiency nanocomposite material featuring a zinc-based metal–organic framework and a novel porous activated carbon derived from bread waste. The prepared nanocomposite, namely Zn-MOF-5@BHPAC, has been synthesized by a low-temperature hydrothermal process and coated onto the surface of a stainless steel wire with epoxy glue. The fabricated fiber has been employed as an SPME fiber applied in the extraction and pre-concentration of some nonsteroidal anti-inflammatory drugs (NSAIDs) before their high-performance liquid chromatography-ultraviolet (HPLC-UV) studies. The characterization studies were performed utilizing field emission scanning electron microscopy, elemental mapping, energy-dispersive X-ray spectroscopy, elemental analyzer, Fourier-transform infrared spectroscopy, and Brunauer–Emmett–Teller surface area analysis. Under the optimal conditions, the method demonstrated low detection limits (LODs, 0.06–0.15 µg L–1), wide linear ranges (LRs, 0.20–380 µg L–1) with good linearity (R2 > 0.991), good precisions (RSDs < 6.95%), and acceptable relative recoveries (RR > 85%). Using the green and affordable biomass of bread as a novel carbon-rich source is an innovative idea provided in this study. In addition, the hybridization of the obtained carbon-based material with the MOF compound to create a new high-capacity sorbent is another strength of the proposed method. Long service lifetime, economic efficiency, environmental friendliness, and high extraction capability were some of the other advantages of the suggested procedure. Therefore, the method can utilize successfully for the simultaneous determination of NSAIDs (as model analytes) in different matrixes.

An Urgent Industrial Scheme Both for Total Synthesis, and for Pharmaceutical Analytical Analysis of Umifenovir as an Anti-viral API for Treatment of COVID-19

This paper aims to reveal an urgent industrial scheme for a fast and facile total synthesis of umifenovir (arbidol) (by one-pot stages) as an antiviral agent for treating the 2019-nCoV virus via inhibiting its viral replication in the human cells. As COVID-19 takes thousands of lives all around the world, it seems that the medicinal resources would not be enough to supply billions of peoples currently living on the planet. Thus, this pandemic and its subsequent impacts on the natural order of our life would be one of the most important threats against the entire human race. In this project, we have made attempts to find an operative approach for synthesizing this compound as an active pharmaceutical ingredient (API), which showed it could be effective in inhibiting the newly emerged coronavirus.. The designed scheme uses relatively cheap precursors and contains one pot stage instead of seven time-consuming and more costly linear steps. Moreover, safe and cheap solvents have been used like water and ethanol, instead of toxic ones like methanol and pyridine which could cause rejection of the API in the organic volatile impurities (OVI) test of pharmacopeia analysis, as well as increase the concern of inflammability, explosivity, and carcinogenic properties of those common solvents. The most important pharmaceutical analytical methods containing OVI test (mainly ethanol (about 171 ppm) much lower than the limits, by gas chromatography-Flame Ionization Detector (GC-FID) instrument), assay content (about 99.6% by potentiometric titration), and related purity analysis (by high-performance liquid chromatography-Ultraviolet Detector (HPLCUV)) (about 99.8%) were performed and described to give a more clear industrial scheme.

Application of Fe3O4@TbBd nanobeads in microextraction by packed sorbent (MEPS) for determination of BTEXs biomarkers by HPLC–UV in urine samples

A relatively new adsorbent based on covalent organic frameworks (COFs) was employed for the first time to extract and determine Trans, trans-muconic acid (tt-MA), Mandelic acid (MA), Hippuric acid (HA), and 3-Methylhippuric acid (m-MHA) in urine. For this purpose, microextraction was performed using the packed sorbent (MEPS) method. Following the extraction process, the prepared samples were specified via the high-performance liquid chromatography-ultraviolet detector system. The precipitation polymerization was applied to synthesize the Fe3O4@TbBd nanobeads, and the morphological and dimensional structures of the products were specified with FE-SEM images. Some key variables affecting the extraction efficiency (i.e., sample volume, elution volume, condition and washing solvents, type and volume of elution solvent, extraction cycles, temperature, and pH of the sample solution) were investigated. In ideal conditions, the limit of detection (LOD) was obtained from 0.02 µg/ml for tt-MA to 0.5 µg/ml for MA. Calibration curves (at five-point) were plotted in the range 0.05–5 µg/ml for tt-MA to 1–300 µg/ml for MA (R2 > 0.98). Moreover, intra- and inter-day precision values were 3.1–5.5 and 4.6–9.8%, respectively. The developed method was successfully employed to determine four analytes in three concentrations (low, medium, and high QCs). The results showed a satisfactory recovery (70–87%). COF-MEPS technique is a rapid, easy, user-friendly, and environment-friendly method for separating the minimum values of all BTEXs chief biomarkers from urine samples without using complicated processes and only with one adsorbent. Also, it can be a good alternative for biomonitoring the workers exposed to BTEX compounds in occupational and environmental access.