High-performance Liquid Chromatography-ultraviolet Detection Research Articles

Surfactant-assisted salting-out homogenous liquid–liquid extraction based on deep eutectic solvents using central composite design; application in the extraction of natamycin from fruit juices before its determination by HPLC-UV

In this study, for the first time, surfactant-assisted deep eutectic solvent-based salting-out homogenous liquid-liquid extraction performed in a narrow-bore tube has been introduced as a new sample pretreatment approach and used for the isolation of natamycin from fruit juices. In this method, firstly, tween 80 (as a surfactant) and a water-miscible ternary deep eutectic solvent composed of choline chloride: acetic acid: butanol (as an extractant) were added to the sample solution and a homogenous state was formed. This solution was transferred into a narrow-bore tube and in the following, the homogenous solution was broken by addition of sodium chloride (as a phase separation agent). By this action, the analyte was extracted into the produced tiny droplets of extractant. This phase was quantified by high–performance liquid chromatography-ultraviolet detection. Experimental conditions of the developed extraction procedure were investigated and optimized by means of central composite design with variables including surfactant and extraction solvent volume, pH, and sodium chloride amount. Under optimum conditions, low limits of determination and quantification (0.78 and 2.60 ng mL−1, respectively), acceptable repeatability (relative standard deviations of 4.9 and 7.1% for intra- and inter day precisions at a concentration of 25 ng mL−1), and satisfactory extraction recovery (76%) were obtained using the proposed method. At the end, the suggested method was effectively utilized for the analysis of natamycin in different juice samples.

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.

Amino functionalized magnetic covalent organic framework for magnetic solid-phase extraction of sulfonylurea herbicides in environmental samples from tobacco land.

An amino-functionalized magnetic covalent organic framework composite TpBD-(NH2 )2 @Fe3 O4 (Tp=Tp1,3,5-triformylphloroglucinol, BD-(NH2 )2 is 3,3',4,4'-biphenyltetramine) was prepared by post-synthesis modification. Due to its abundant benzene rings and amino groups, large specific surface area and porous structure, the prepared TpBD-(NH2 )2 @Fe3 O4 exhibits high extraction efficiency toward sulfonylurea herbicides. Based on this, a new method of magnetic solid-phase extraction with TpBD-(NH2 )2 @Fe3 O4 as the sorbent combined with high-performance liquid chromatography and ultraviolet detection was developed for trace analysis of sulfonylurea herbicides in environmental water, soil and tobacco leaves samples from tobacco land. Under the optimized conditions, the limits of detection within 0.05-0.14 μg/L were achieved with a high enrichment factor of 217-260-fold, and the relative standard deviations were 4.9-7.5% (n=7, c=0.5 μg/L). The linear range was around three orders of magnitude with the square of correlation coefficient higher than 0.9936. The method was applied to analyze five sulfonylurea herbicides in the environmental water, soil, and tobacco leave samples collected from tobacco land. No sulfonylurea herbicides were detected in these samples. The recoveries of target sulfonylurea herbicides in spiked environmental water, soil, and tobacco leaf samples were found in the range of 90.7-104, 70.7-99.0, and 59.3-97.8%, respectively. The results illustrate that the established TpBD-(NH2 )2 @Fe3 O4 -magnetic solid-phase extraction- high-performance liquid chromatography-ultraviolet detection method is efficient for the analysis of trace sulfonylurea herbicides in environmental samples.

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.

Preconcentration of liposoluble constituents in Salvia Miltiorrhiza using acid-assisted liquid phase microextraction based on a switchable deep eutectic solvent

A switchable deep eutectic solvent-based liquid-phase microextraction was proposed and applied to the preconcentration and determination of liposoluble quality-markers of diterpenoid quinones (dihydrotanshinone I, cryptotanshinone, tanshinone I, and tanshinone IIA) in traditional Chinese medicine coupled with high performance liquid chromatography-ultraviolet detection. In the procedure, the hydrophilic deep eutectic solvent of diethanolamine-hexanoic acid (molar ratio 1:1) was prepared and added into the sample phase as an extractant, and a homogeneous solution was formed under slight vortex stirring. After the addition of HCl solution, the deep eutectic solvent miscible with the sample phase was converted to hydrophobic form, and a cloudy solution was generated. Then, the upper hydrophobic layer enriching the target analytes was collected through centrifugation for high performance liquid chromatography analysis. Several critical parameters affecting the extraction performance including the composition and consumption of switchable deep eutectic solvent, the type and amount of acid, salt amount and extraction time were investigated and optimized. Moreover, the structures of the deep eutectic solvent and the recovered hydrophobic layer were both characterized using Fourier transform infrared spectroscopy, further demonstrating the switching mechanism of the extractant during the extraction process. Under the optimal conditions, enrichment factors of diterpenoid quinones ranged from 59 to 274. Good linearities (r≥0.9963), low detection limits (0.5–0.7 ng/mL), satisfactory precisions (relative standard deviations 0.5%-8.6%) and accuracies (recoveries 94.6%-104.6%) were also obtained. Comparing the proposed switchable deep eutectic solvent-based liquid-phase microextraction with other published methods, the characteristics of the procedure were summarized. The developed method was successfully applied for the preconcentration of four liposoluble diterpenoid quinones from a traditional Chinese herbal medicine of Salvia Miltiorrhiza.

Enhancing enrichment ability of Co-Al- layered double hydroxides-mixed matrix membrane microextraction by deep eutectic solvent for analysis of warfarin in biological samples and its quantification via high-performance liquid chromatography-ultraviolet detection

Recent studies on the use of mixed-matrix membrane (MMM) in microextraction methods have considered the use of membrane extraction phase with wide surfaces and high porosity. Here, for the first time, the effect that deep eutectic solvents (DESs) have on the performance of MMM was investigated. The Co-Al-layered double hydroxides mixed matrix membrane (CO-Al-LDH-MMM) was prepared by immobilization of LDH on the pores of the hollow fiber membrane and used as a microextraction device. Deep eutectic solvent via hydrophilic and π-π interactions, aided the dissolution of analyte in the fiber membrane lumen and increases their adsorption onto LDH. Thus, a microextraction method based on the novel LDH-MMM–deep eutectic solvent (LDH-MMM-DES) system was developed and used for the extraction, preconcentration, and quantification of warfarin (as a model analyte) in biological samples. The principal variables that affective influence microextraction efficiency, including the extraction time, type of DES, stirring rate, desorption time, type of eluent solvent, and pH of the sample solution, were screened via Plackett-Burman design and then variables effective optimized by Box-Behnken design. Under the optimum conditions obtained, the developed method showed a good working range (R2 ≥ 0.9951). The limit of detection (LOD) and the limit of quantification (LOQ) ranged from 0.03 μg L−1 (water) to 0.30 μg L−1 (human plasma sample) and from 0.099 μg L−1 (water) to 0.999 μg L−1 (human plasma sample) variables, respectively. The intraday precision was in the range of 2.5–5.6. In order to experiment with the precision and applicability of the Co-Al LDH-MMM DES method, spiking recovery studies were performed in biological samples (urine and humane plasma samples). The recovery results for urine and plasma samples were calculated as 90–91% and 88–93 %, respectively. The results confirmed that the presented method would be promising for the analysis of warfarin in biological samples.

Preparation and performance analysis of monodisperse glycidyl methacrylate modified restricted access media‐imprinted materials

Using monodisperse poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) as the matrix, and pefloxacin template molecules, a novel restricted-access medium molecularly imprinted polymers with Bovine serum albumin crosslinked on its surface was prepared through reversible addition-fragmentation chain-transfer polymerization. Then, the obtained material was employed in dispersive solid-phase extraction to analyze the fluoroquinolones in untreated egg samples by high-performance liquid chromatography-ultraviolet detection. Adsorption performance revealed a good binding amount (40.72mg/g), fast binding kinetics (25min), satisfactory selectivity, and good ability to eliminate matrix interference. The reusability experiments indicated the materials have good reusable performance after repetition. Under the optimized conditions, restricted access media-molecularly imprinted polymers-dispersive solid-phase extraction was combined with high-performance liquid chromatography-ultraviolet to enrich fluoroquinolones in untreated eggs, good limit of detection (1.31-3.15 μg/L) and high recovery (89.5-96.8%) were obtained. The results showed that the prepared restricted-access material is promising for the direct detection of antibiotics in complex samples.

Efficient Extraction and Determination of Carbamate Pesticides in Vegetables Based on a Covalent Organic Frameworks with Acylamide Sites

It is an important challenge to effectively extract and determine pesticides in complex samples. Covalent organic frameworks (COFs) are burgeoning porous crystalline organic materials with good environmental resistance, thus demonstrating great potential as adsorbents in contaminants detection. In this work, we design and synthesize a novel COF-TpDB via 1,3,5-triformylphloroglucinol (Tp) and 4,4′-diaminobenzoylanilide (DB) as well as its packed cartridge for solid phase extraction (SPE) of carbamate pesticides. Simulation calculations showed H-bonding facilitates the adsorption interactions between the carbamate pesticides and TpDB. A method was developed by coupling TpDB as SPE sorbents with high performance liquid chromatography-ultraviolet (HPLC-UV) detection to determine trace carbamate pesticides in vegetables. The established method showed a wide linear range of 0.1–200 ng mL−1 and low limit of detections (0.005–0.05 ng mL−1) for four carbamate pesticides. The applicability of TpDB as adsorbent was investigated for determination of trace carbamate pesticides residue in vegetables with satisfactory recoveries of four carbamates in the range of 80.4–101.2%. The results demonstrated that the COF-TpDB offer great potential for efficient extraction of carbamate pesticides from complicate matrices.

Determination of Metal Ions in Pinellia ternata by High Performance Liquid Chromatography-Ultraviolet Detector

In this study, trace amounts of heavy metal ions copper, lead, mercury and cobalt in Pinellia ternata samples were detected by ionic liquid ultrasonic assisted dispersion liquid–liquid microextraction, combined with high performance liquid chromatography-ultraviolet detector. The method used sodium diethyldithiocarbamate as complexing agent and phosphoric acid ionic liquid Trihexyl(tetradecyl) phosphine bis[(2,4,4-trimethyl)] amyl phosphonate (cyclophosphate IL104) as extractant. Methanol: 0.2% phosphoric acid (60:40) was used as mobile phase for separation and UV detector was used for detection, the flow rate was 1 mL/min and the injection volume was 10 μL. In this paper, the effects of sample pH, complexing agent concentration, ultrasonic time, centrifugation time and speed and ionic strength were optimized. Under the optimal conditions (50 μL ionic liquid cyclic phosphine IL104, pH = 5, 0.5% sodium diethyldithiocarbamate, ultrasonic time of 30 min, centrifugation speed of 4000 r/min, 0.1 g NaCl), the recovery of spiked standard was 89.0~98.2%. High performance liquid chromatography had the characteristics of low detection limit, accurate and reliable determination results, high sensitivity, strong specificity and good reproducibility.

Countercurrent Salting-out Homogenous Liquid-Liquid Extraction and Dispersive Liquid-Liquid Microextraction Based on the Solidification of Floating Organic Drop Followed by High-Performance Liquid Chromatography for the Isolation and Preconcentration of Pesticides from Fruit Samples.

Pesticides are widely used to control pests and prevent diseases in crops, including cereals, vegetables, and fruits. Due to factors such as the persistence of pesticides, bioaccumulation, and potential toxicity, pesticide residue monitoring in foodstuffs is very important. In the current research, we proposed a novel approach using countercurrent salting-out homogenous liquid-liquid extraction combined with dispersive liquid-liquid microextraction based on the solidification of floating organic droplets (DLLME-SFO) for isolation and preconcentration of pesticides from aqueous samples for analysis by high-performance liquid chromatography-ultraviolet detection (HPLC-UV). In brief, sodium chloride was used as a separation reagent, in a small glass column, through which was passed a mixture of an aqueous solution of, for example, fruit juice and acetonitrile. In this process, the droplets rose through the column and a separated layer would be formed on the remained an aqueous phase. Following that, acetonitrile as the organic phase was mixed with 50.0 µL of 1-undecanol (extraction solvent). To further enrich the analytes, the mixture was injected into 5 mL of a 4% w/v sodium chloride solution and placed in a tube for the DLLME-SFO. Under optimal conditions, a dynamic linear range of 0.5-500 μg/L, extraction recovery of 65-85%, enrichment factors of 108-142, and limit of detection of 0.2-0.4 μg/L were obtained for the organophosphorus pesticides analysed. In addition, the repeatability and reproducibility from five replicate measurements of the pesticides (100 μg/L) were within the ranges of 3.5-5.1% and 4.5-6.3%, respectively . In this research, a new extraction method based on countercurrent salting out homogeneous liquid-liquid extraction combined with DLLME-SFO has been applied for the determination of pesticide residues in fruits, juice and environmental samples before using HPLC-UV analysis. The combined method not only leads to high enrichment factors, but can also be used in complex matrices (such as fruits, juices and high-salt solutions) without pre-treatment or dilution. Compared with other sample preparation methods, this analysis procedure has many advantages, including simplicity, ease of operation, high pre-enrichment factor, low detection limit and relatively short analysis time. Combination of CCSHLLE and DLLME-SFO was applied for the analysis of organophosphorous pesticide residues in fruit, fruit juices and environmental samples. The DLLME-SFO method avoided using high density and toxic extraction solvents. LODs are achievable at ng L-1 using CCSLLE-DLLME-SFO-HPLC-UV.

A novel polyhedral oligomeric silsesquioxane-based hybrid monolith as a sorbent for on-line in-tube solid phase microextraction of bisphenols in milk prior to high performance liquid chromatography-ultraviolet detection analysis

An on-line in-tube solid-phase microextraction (in-tube SPME) coupled with high-performance liquid chromatography (HPLC) method was proposed based on a novel polyhedral oligomeric silsesquioxane (POSS)-hybrid monolith for the determination of four bisphenols (BPs) in milk. The monolith was synthesized using acrylamide (AM) and monomethacrylate-functionalized POSS (mono-MA-POSS) as functional monomers to copolymerize with ethylene dimethacrylate (EDMA). Due to the abundant hydrogen bonding, π-π and hydrophobic interaction sites, the synthetic monolith displayed satisfying extraction performance for target BPs. Under the optimized conditions, the developed on-line in-tube SPME-HPLC method exhibited low limits of detection (LODs) (0.030–0.055 ng mL−1). The spiked recoveries were between 85.4 % and 111.8 %, and the relative standard deviations (RSDs) were less than 3.5 % for all the analytes. The results showed that the proposed method provided alternative for the analysis of BPs in complex samples.

Elevated Temperature Air-Assisted Liquid-Liquid Microextraction of Pseudoephedrine from Human Urine Samples Coupled with High-Performance Liquid Chromatography-Ultraviolet Detection

Background: Pseudoephedrine is a broadly used drug for the clinical treatment of bronchitis, respiratory allergies, and cancer pains. However, the use of pseudoephedrine is restricted by several medicinal commissions like International Olympic Committee (IOC). In this study, a reliable, inexpensive, green, and sensitive microextraction method has been developed for extraction and preconcentration pseudoephedrine in urine samples. Methods: It is based on an air-assisted liquid-liquid microextraction (AALLME) technique in which choline chloride: p-chlorophenol deep eutectic solvent (DES) was used as the extraction. The extracted analyte was determined by a high-performance liquid chromatography (HPLC)-ultraviolet detector. The effective factors on the efficiency of the method such as kind of extraction solvent, pH of sample solution, extraction time, and ionic strength were investigated. Results: Under the optimized conditions, the extraction recovery (ER) and enrichment factors(EFs) were 89% and 222, respectively. The method detection limit, relative standard deviation(RSD), and linear range were 0.21 ng mL-1, 4.9%, and 0.69-1000 ng mL-1, respectively. Conclusion: The validated method was successfully performed on different urines samples obtained from the persons who were under treatment with pseudoephedrine.

New low viscous hydrophobic deep eutectic solvents for the ultrasound-assisted dispersive liquid-liquid microextraction of endocrine-disrupting phenols in water, milk and beverage

In the present work, several new hydrophobic deep eutectic solvents (HDESs) were prepared with quaternary ammonium salts as hydrogen bond acceptors (HBAs) and salicylate esters as hydrogen bond donors (HBDs). Then, the obtained HDESs were used as extraction solvents to establish an ultrasound-assisted dispersive liquid-liquid microextraction method combined with high-performance liquid chromatography-ultraviolet detection technique for the determination of four endocrine-disrupting phenols (EDPs) compounds. One of the obtained HDESs composed of tetrabutylammonium chloride (N4444Cl) and methyl salicylate possessed a viscosity of 89.28 mPa•s lower than most reported ionic HDESs (>200 mPa•s), and the low viscous HDES was selected as the optimal extraction solvent. Several key parameters affecting the extraction efficiency were investigated, including the type and volume of HDES, ultrasound time, sample solution pH and salt addition. Under the optimized experimental conditions, the proposed method had good coefficients of determination (R2 > 0.9976) in the linear range of 0.5–400 µg•L−1, the limits of quantification and limits of detection respectively were 0.5–2.5 µg•L−1 and 0.25–1 µg•L−1, and the recoveries were in the range of 81.79–109.82%. Finally, the method was used for the preconcentration and determination of EDPs in different samples, including bottled water, tea beverage and milk.

Pharmacokinetics and tissue distribution characteristics of the novel photosensitizer 32-(4-methoxyphenyl)-152-aspartyl-chlorin e6

二氢卟吩类衍生物32-(4-甲氧基苯基)-152-天冬氨酸-二氢卟吩e6(DYSP-C34)是从程海湖螺旋藻中提取并合成的新型光敏剂。研究DYSP-C34在生物体内的药代动力学及组织分布过程对光动力疗法(PDT)的有效性和安全性至关重要。该文运用高效液相色谱-紫外(HPLC-UV)检测技术,建立了大鼠血浆中DYSP-C34的检测方法。采用沉淀蛋白-液液萃取法处理血浆和组织样品,采用Unitary C18色谱柱(250 mm×4.6 mm, 5 μm)分离,流动相为甲醇-5 mmol/L四丁基磷酸氢铵缓冲盐溶液(70:30, v/v),流速为1.0 mL/min,进样量为20 μL,检测波长为400 nm,柱温为40 ℃。实验结果表明,大鼠血浆药物质量浓度在1~200 μg/mL范围内线性良好,判定系数(r2)为0.9941。在低、中、高(8、40、120 μg/mL)3个添加水平下的提取回收率分别为74.39%、69.71%和65.89%,日内和日间相对标准偏差(RSD)均在5%以内。运用此方法测定静脉注射DYSP-C34(16 mg/kg)后大鼠血浆中以及荷瘤小鼠组织中的药物浓度,采用DAS 2.0计算出药物半衰期t1/2z为6.98 h,药-时曲线下面积AUC(0-∞)为1025.01 h·mg/L,平均驻留时间MRT(0-∞)为9.19 h。DYSP-C34在荷瘤小鼠体内的分布结果显示,DYSP-C34可以在肿瘤组织中蓄积,并具有一定的滞留作用。综上,该文建立了大鼠血浆中DYSP-C34的HPLC-UV测定方法,并进行了方法学验证,此方法简便、快速,结果准确。阐明了DYSP-C34在静脉给药方式下大鼠体内药代动力学和荷瘤小鼠组织中的分布特征,对临床合理用药和药效学研究具有重要意义。

Dispersive solid phase extraction based on reduced graphene oxide modified Fe3O4 nanocomposite for trace determination of parabens in rock, soil, moss, seaweed, feces, and water samples from Horseshoe and Faure Islands

This study reports an efficient, green, sensitive and simple analytical protocol for trace determination of methyl paraben, ethyl paraben, propyl paraben, butylparaben and benzyl paraben by high-performance liquid chromatography-ultraviolet detection (HPLC-UV). The analytes were preconcentrated using an ultrasonication supported (US) dispersive solid phase extraction (DSPE) method based on reduced graphene oxide (rGO) modified iron nanoparticles (US-Fe3O4@rGO-DSPE). A reversed-phase C18 column and an isocratic elution program comprising of 20 mM phosphate buffer (pH 4.50) and acetonitrile(58:42, v/v) were used to elute and separate the analytes for detection. The limits of detection determined for the analytes were very low and were in the range of 0.02 – 0.16 ng mL−1. The coefficients of determination obtained for the analytes ranged from 0.9973 to 0.9998, and this validated good linearity of the method.Percent relative standard deviations obtained in the range of 2.5 – 10.6% verified the method’s high intraday repeatability. Accuracy of the proposed method was assessed with spiking experiments performed on complex sample matrices. Percent recoveries calculated for spiked soil, artificial seawater and seaweed samples were in acceptable ranges of 95 – 121%, 87 – 117% and 85 – 111%, respectively. These figures of merit suggest that HPLC-UV coupled with the US-Fe3O4@rGO-DSPEmethod is suitable for the determination of parabens in Antarctic samples.

Pharmacokinetics and bioavailability of meloxicam in rainbow trout (Oncorhynchus mykiss) broodstock following intravascular, intramuscular, and oral administrations.

The pharmacokinetics and bioavailability of meloxicam were investigated after single intravascular (IV), intramuscular (IM), and oral dose of 1mg/kg in rainbow trout broodstock at 11±1.2°C. A total of 36healthy rainbow trout (Oncorhynchus mykiss) broodstock weighing 1.40±0.26kg was used for the investigation. Plasma concentrations of meloxicam were measured with high-performance liquid chromatography-ultraviolet detection, and pharmacokinetic parameters were calculated by non-compartmental analysis. The elimination half-life for IV, IM, and oral routes was 3.63, 4.55, and 2.95h, respectively. The IV route for meloxicam showed the total clearance of 0.05 L/h/kg and volume of distribution at a steady state of 0.20L/kg. The peak plasma concentration was 2.97μg/ml for the IM route and 0.84μg/ml for the oral route. The bioavailability was 78.45% for the IM route and 21.48% for the oral route. Meloxicam following IM and oral administration displayed short t1/2ʎz . The short t1/2ʎz could be an advantage for the short-term use in acute conditions. The IM route with the good bioavailability can be preferred for the treatment of various conditions. However, developing new oral formulations with the good bioavailability for meloxicam is necessary to minimize stress and trauma through minimal handling in rainbow trout broodstock.

Imine-linked covalent organic frameworks coated stir bar sorptive extraction of non-steroidal anti-inflammatory drugs from environmental water followed by high performance liquid chromatography-ultraviolet detection

In this study, spherical imine-linked covalent organic frameworks (COFs) were fabricated from 2,5-dimethoxybenzene-1,4-dialdehyde (DMTP) and 1,3,5-tris (4-aminophenyl) benzene (TAPB) and named as TAPB-DMTP-COFs. The resulting powders were coated onto bare glass bars via physical-adhesion to obtain TAPB-DMTP-COFs coated stir bars. The self-made stir bars exhibited higher extraction efficiency (74–85%) and faster dynamics (50 min) towards non-steroidal anti-inflammatory drugs (NSAIDs) over ethylene glycol-Silicone (42–68%, 180 min) and polydimethylsiloxane (3–61%, 180 min) coated stir bars. Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy (XPS), zeta potential and water contact angle were employed to provide a comprehensive understanding of the adsorption mechanism between the coating and analytes. The results displayed that methoxy group worked as an adsorption site helping the adsorption of interest NSAIDs onto the TAPB-DMTP-COFs coating and hydrogen bonds formed between the O atoms and the analytes. Additionally, the adsorption mechanisms possibly also involved π-π interaction and hydrophobic interaction. Moreover, TAPB-DMTP-COFs coated stir bars exhibited good stability and could be reused more than 60 times. Subsequently, a method by combining TAPB-DMTP-COFs coated stir bar sorptive extraction (SBSE) with liquid chromatography (HPLC)-ultraviolet detector (UV) was established for the determination of four NSAIDs in environmental waters. Under the optimized conditions, the established method showed a wide linear range of 0.2/1–500 μg/L for interest NSAIDs, the limits of detection varied from 0.039 to 0.312 μg/L. Yangtze River water, East Lake water and Spring water were subjected to the proposed method, the recoveries in spiked samples were 84.7–104%, 81.2–101% and 82.6–97.6%, respectively.

Construction of imine-linked covalent organic framework as advanced adsorbent for the sensitive determination of chlorophenols

Food safety is a great concern of the general public. Chlorophenols (CPs) as organic pollutant can be found in drinking water and foods, causing serious harm to human health. Herein, imine-linked covalent organic frameworks (COFs), named as TAPT-AN-COF, was synthesized by aniline modulation strategy through condensation of 1,3,5-triformylphoroglucinol and 4,4′,4′'-(1,3,5-Triazine-2,4,6-triyl)trianiline with aniline as modulator. The prepared TAPT-AN-COF possesses good crystallinity and regular morphology, displaying excellent adsorption capability towards CPs pollutants. Thus, the TAPT-AN-COF was used as novel adsorbent for off-line solid-phase extraction of four CPs (2-CP, 3-CP, 2,3-CPs, 2,4-CPs) from bottled water, tea drink and honey samples before high performance liquid chromatography-ultraviolet detection. Under optimal conditions, wide linear range, low detection limits and satisfactory extraction recovery were gained. The π-stacking and hydrophobic interactions between the TAPT-AN-COF and the analytes played an important role in the adsorption. The established method has a great potential in determining other hydrophobic aromatic compounds.

Comparison of organic and deep eutectic solvents based dispersive liquid-liquid microextraction for the analysis of phytosterols in cow milk combined with high-performance liquid chromatography-ultraviolet detector.

In the present work, a dispersive liquid-liquid microextraction approach has been developed for extraction of four phytosterols (stigmasterol, β-sitosterol, campesterol, and brassicasterol) from cow milk samples using organic and deep eutectic solvents and the results were critically compared. The extracted analytes were determined using high performance liquid chromatography. In the developed method, carbon tetrachloride and choline chloride:p-chlorophenol deep eutectic solvent were selected to use as the best extraction solvent. Effective parameters and validation data were studied for both methods, independently. Under optimum conditions, limits of detection and quantification were within the ranges of 0.3-0.9 and 1.0-3.0ng/mL for organic solvent based dispersive liquid-liquid microextraction and 0.09-0.32 and 0.3-1.0ng/mL for deep eutectic solvent based dispersive liquid-liquid microextraction, respectively. Good coefficient of determinations and relative standard deviations obtained for the methods were ≥0.994 and ≤7.6%, respectively. The introduced method was performed on different milk samples for the determination of target analytes using both solvents and the results were analyzed statistically by the t-test.

Determination of Bisphenol A in Packed Milk and Mineral Water Samples Marketed in Tabriz (Iran) in 2020 Using High-performance Liquid Chromatography-ultraviolet Detector

Bisphenol A is a monomer used in production of several plastic resins in food storage containers. Residue of BPA in plastics can be found in foods filled into the containers. Due to this fact that BPA is an endocrine disruptor, its dietary exposure must be estimated. In this method, the analyte was extracted using a dispersive liquid-liquid microextraction procedure from water and milk samples. For this purpose, a mixture of acetone and chloroform (142 µL) was dispersed into the water sample or aqueous phase obtained from milk after its deproteinization with trichloroacetic acid. In both samples, the obtained cloudy solutions were centrifuged and the sedimented phase analyzed by high performance liquid chromatography-ultraviolet detector. Analytical features of the method consist of limits of detection (0.44 ng mL-1 in water and 0.51 ng mL-1 in milk samples) and quantification (1.47 ng mL-1 in water and 1.72 ng mL-1 in milk samples), linearity (r2=0.992), precision (RSD≤11.1%), and accuracy (RSD≤3%) were studied under final conditions. The results showed that the obtained results are acceptable. Different milk and water samples were analyzed using the developed method and BPA was found in several samples in the ranges of 11.2-32.6 and 9.6-23.5 ng mL-1 in milk and water samples, respectively. Comparing the results with maximum residue limit established by European Commission showed that BPA content was higher than the permitted level.