High-performance Liquid Chromatography-diode Array Detection Research Articles

Improved Extraction Efficiency and Antioxidant Activity of Defatted Canola Meal Extract Phenolic Compounds Obtained from Air-Fried Seeds.

This study investigated the efficacy of roasting pre-treatment by air frying to enhance the extraction and recovery of the predominant sinapic acid derivatives (SADs) from roasted canola meal and the antioxidant potential of the methanolic extracts. Canola meal was obtained by air frying canola seed at 160, 170, 180 or 190 °C for 5, 10, 15 or 20 min. Oil was extracted using the Soxhlet method, and the de-oiled meal fraction was air-dried. Phenolic compounds were isolated using ultrasound-assisted extraction with 70% (v/v) methanol and then quantified by high-performance liquid chromatography-diode array detection. The antioxidant potential of the defatted meal methanolic extracts was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and metal ion-chelating activity (MIC) assays. The highest total phenolic content of 3.15 mg gallic acid equivalent/g dry weight was recorded in the defatted meal extract from seeds pre-treated with air frying at 190 °C for 15 min. Sinapine, sinapic acid and an unknown compound at a retention time (RT) of 26.6 min were the major sinapates identified in the defatted meal with the highest concentrations of 7572 ± 479.2 µg/g DW, 727 ± 43.45 µg/g DW and 1763 ± 73.5 µg/g DW, respectively, obtained at 160 °C for 5 min. Canolol (151.35 ± 7.65 µg/g DW) was detected after air frying at a temperature of 170 °C for 20 min. The FRAP and MIC correlated positively (r = 0.85) and generally decreased with increased air frying temperature-time conditions. The highest FRAP and MIC values of 0.53 mM and 80% were obtained at 160 °C for 5 and 20 min, respectively. The outcome of this study will contribute new knowledge that could improve the value addition and by-product utilization of canola seeds.

Phenolic compounds and extracts from Crotalaria calycina Schrank potentially alleviate pain and inflammation through inhibition of cyclooxygenase-2: An in vivo and molecular dynamics studies

Crotalaria calycina Schrank is a local Bangladeshi plant well-accepted by the tribal population for its medicinal properties. The primary approach of our study was to uncover the analgesic and anti-inflammatory potential of methanol extract of C. calycina stem in mice model with in silico molecular docking and molecular dynamics simulation approach. Phenolic compounds were identified and quantified from the extract through high-performance liquid chromatography-diode array detector (HPLC-DAD) analysis. Writhing assay through injection of acetic acid, licking assay through formalin injection, and finally, hot plate assay was employed to observe the analgesic activity. The carrageenan-induced paw edema model was employed to determine the anti-inflammatory potential of the extract. In silico molecular docking and molecular dynamics were also run to validate the in vivo study results. Eight polyphenolic compounds from the extract were identified and quantified via HPLC-DAD analysis, and (-) epicatechin was most abundantly distributed (87.15 ± 0.24 mg/100 g dry extract). In vivo study revealed that 400 mg/kg dose significantly inhibited (P < 0.01) the writhing response in the writhing assay and demonstrated the highest percent of inhibition of licking (70.67%) in the late part of the licking test. The same extract dose produced the highest (74.71%) percent of maximal effect (% MPE) in the hot plate assay. It demonstrated the highest percent of edema inhibition (68.00%) in the fourth hour of the paw edema assay. Molecular docking and molecular dynamics simulation of (-) epicatechin, caffeic acid, and kaempferol with cyclooxygenase-2 revealed that they have similar interactions to the standard inhibitor celecoxib. These valuable bioactive compounds may induce significant analgesic and anti-inflammatory properties in MECCS. Therefore, based on the findings of this study, it can be concluded that C. calycina stem can be a prospect in the medicinal field due to its remarkable analgesic and anti-inflammatory effect.

Anticancer and Antioxidant Activity of Water-Soluble Polysaccharides from Ganoderma aff. australe against Human Osteosarcoma Cells.

Wild mushrooms have gained great importance for being a source of biologically active compounds. In this work, we evaluate the anticancer and antioxidant activity of a water-soluble crude polysaccharide extract isolated from the fruiting bodies of the Ganoderma aff. australe (GACP). This mushroom was collected in San Mateo (Boyacá, Colombia) and identified based on macroscopic and microscopic characterization. GACP was characterized by UV-Vis spectroscopy, Fourier-transform infrared spectroscopy, high-performance liquid chromatography-diode array detector, and nuclear magnetic resonance. The antiradical and antioxidant activity were evaluated by different methods and its anticancer activity was verified in the osteosarcoma MG-63 human cell line. Chemical and spectroscopic analysis indicated that GACP consisted of β-D-Glcp-(1→, →3)-β-D-Glcp-(1→ and α-D-Glcp-(1→ residues. The results of the biological activity showed that GACP exhibited high antioxidant activity in the different methods and models studied. Moreover, the results showed that GACP impaired cell viability (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay) and cell proliferation (clonogenic assay) in a dose-response manner on MG-63 cells. The findings of this work promote the use of mushroom-derived compounds as anticancer and antioxidant agents for potential use in the pharmaceutical and food industries.

Simultaneous quantitative analysis of 11 constituents in Viticis Fructus by HPLC-HRMS and HPLC-DAD combined with chemometric methods.

Viticis Fructus is the dried ripe fruit of Vitex trifolia L. (VTF) or V. trifolia subsp. litoralis Steenis (VTLF). Different botanical sources of the same herbal medicines may have different clinical efficacies, but few studies have reported the comparative identification of VTF and VTLF. To establish a high-performance liquid chromatography (HPLC) method for the simultaneous assay of 11 constituents in Viticis Fructus, to compare the chemical compositions of VTF and VTLF, and to identify chemical markers for the discrimination and quality evaluation of the two botanical origins of Viticis Fructus. An HPLC-diode array detection (DAD)-high-resolution mass spectrometry (HRMS) method was developed for the simultaneous separation and quantification of 11 constituents in 21 batches of Viticis Fructus samples from different sources in China. Moreover, chemometrics were performed to compare and discriminate VTF and VTLF samples. The results from 11 batches of VTF and 10 batches of VTLF were compared for 11 components, of which 3,4-dicaffeoylquinic acid and 3,5-dicaffeoylquinic acid were identified and quantified in Viticis Fructus for the first time. The quantitative analysis showed significantly higher chlorogenic acid and casticin contents in VTLF than in VTF, and the chemometric analysis indicated that chlorogenic acid and casticin were responsible for the significant differences between VTF and VTLF; these two compounds might be used as chemical markers to distinguish the two original plant sources of Viticis Fructus. The present work provides useful information for understanding the chemical differences between VTF and VTLF. This work also provides feasible methods for the quality evaluation and discrimination of herbal medicines originating from multiple botanical sources.

A Validated HPLC-Diode Array Detection Method for Therapeutic Drug Monitoring of Thiopurines in Pediatric Patients: From Bench to Bedside.

Thiopurine drugs are part of the therapeutic armamentarium for pediatric patients suffering from inflammatory bowel disease (IBD) and acute lymphoblastic leukemia (ALL). The therapeutic drug monitoring of these drugs, consisting of measurements of the thiopurine metabolites thioguanine nucleotides (TGN) and methylmercaptopurine nucleotides (MMPN) are used to optimize the effectiveness of treatment and prevent adverse effects. In this context, we developed and validated a high-performance liquid chromatography-diode array detection (HPLC-DAD) method for the simultaneous quantification of thiopurine metabolites according to the most recent International Council for Harmonisation (ICH) guidelines. The calibration curves were built in the clinically relevant range of concentrations for TGN of 300-12,000 nM and for MMPN of 3000-60,000 nM. The limit of detection and the lower limit of quantification were 100 and 300 nM for TGN and 900 and 3000 nM for MMPN, respectively. The percentage of inter-day accuracy and precision (CV%) varied between 85 and 104% and 1.6 and 13.8%. Stability was demonstrated for both of the metabolites for at least 50 days at -20 °C. The proposed HPLC-DAD method showed an appropriate selectivity, specificity, linearity, accuracy, precision and good applicability to samples from patients with IBD and ALL undergoing thiopurine treatment.

Titania hybridized melamine-formaldehyde aerogel for online in-tube solid-phase microextraction of polycyclic aromatic hydrocarbons prior to HPLC-DAD.

In order to improve the selectivity and stability of melamine-formaldehyde (MF) aerogel, it was composited with TiO2 aerogel. A TiO2-MF hybrid aerogel was in situ prepared on the surface of carbon fibers for in-tube solid-phase microextraction (SPME). The extraction performance of TiO2-MF aerogel was regulated by changing the ratio of TiO2 sol and MF sol during the material preparation. Coupled with high-performance liquid chromatography-diode array detection (HPLC-DAD), the extraction tube filled by TiO2-MF aerogel-coated carbon fibers was evaluated with several types of environmental pollutants including polycyclic aromatic hydrocarbons (PAHs), estrogens, and ultraviolet filters. Because of favourable extraction performance of PAHs theywere selected as model analytes, and some important influence factors were optimized for satisfactory sensitivity. The detection limits were in the range 0.05-0.10μg L-1, owing to high enrichment factors (653-1007). The online in-tube SPME-HPLC-DAD method was verified for the determination of trace PAHs in environmental water samples, and acceptable recovery (70-118%) was achieved. The analytical methods also displayed some advantages in comparison with otherreports. Moreover, the extraction tube exhibited satisfactory chemical stability.

Nanoporous Ethylenediamine-Functionalized Metal–Organic Framework MIL-101 for the Removal of Proteins and Antipsychotic Drugs from Serum Samples

The development of functional materials for efficient protein removal and antipsychotic drug extraction in biological samples is attracting great interest. In this study, a nanoscale ethylenediamine-functionalized chromium-based metal–organic framework (MOF) (MIL-101-ED) was designed, synthesized, and applied for the one-step removal of proteins and the extraction of antipsychotic drugs in serum samples. The introduction of ethylenediamine in the MIL-101 nanoparticle (NP), in which amino and carbon chains can enhance the hydrogen-bond interaction and π–π interaction between functionalized MOFs and antipsychotic drugs, i.e., risperidone, etc. The antipsychotic drugs were ionized and amino groups were protonated at pH = 3, due to electrostatic interaction, and the negatively charged drugs were adsorbed on the surface or even entered the pores of MOFs. The adsorption efficiencies of the six kinds of drugs ranged from 80.1 to 101.4%. Owing to the exclusion action, proteins were excluded from MIL-101-ED and the exclusion rate ranged from 91.9 to 94.0%. Furthermore, MIL-101-ED can be easily regenerated and reused four times without a significant reduction in the protein exclusion rate and adsorption capacity. Coupled with high-performance liquid chromatography–diode array detection (HPLC–DAD) strategy, the application of MIL-101-ED for extracting the antipsychotic drugs and their metabolites in serum samples was developed. The recoveries of antipsychotic drugs and their metabolites in serum ranged from 83.2 to 110.8%, and the related detection limits were all <5.55 ng mL–1. Compared to the traditional extraction methods, the pretreatment steps of MIL-101-ED have the advantages of easy operation and reducing the environmental pollution. Here, we propose that MIL-101-ED, as a kind of restricted access media nanophase material, can be applied to extract antipsychotic drugs in serum samples.

Metal organic framework/clay composite for micro-dispersive solid-phase extraction of sulfonamides and penicillins in milk, and synthetic urine solution coupling with HPLC/DAD detection

In this study, composite as a copper-containing metal–organic framework with montmorillonite (MMT) clay was synthesized and applied as an adsorbent for micro-dispersive solid-phase extraction (µ-dSPE) of sulfonamides (SAs) and penicillins (PENs). The synthesized composites including different content of MMT were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, Brunauer-Emmett–Teller surface area, and thermogravimetric analysis. The determination of antibiotics was performed by high-performance liquid chromatography/diode array detection (HPLC/DAD) using C18 column as stationary phase, 0.1 % trifluoroacetic acid in water, and acetonitrile as mobile phase in gradient mode and detection at 270 nm for SAs and 230 nm for PENs. The as-synthesized composites were examined for their adsorption ability towards target antibiotics. The optimized parameter conditions were 10 mg of adsorbent, 5 mL of sample solution at pH 4, 10 min stirring by vortex, 1 mL of acetonitrile:methanol (1:1) as eluent solvent, and 5 min as elution time. Under optimized conditions, the proposed method presented good linearity from 0.5 to 400 µg/L for SAs and from 1 to 400 µg/L for PENs with coefficients of determination (r2) ≥ 0.9947, low limit of detections from 0.10 to 0.15 µg/L for SAs and 0.30 to 1.50 µg/L for PENs, acceptable repeatabilities less than 3.26 % for both groups and good recoveries from 82.3 % to 116.4 % with relative standard deviations less than 3.9 % for both groups in the spiked milk samples and synthetic urine solution. The developed µ-dSPE method following HPLC/DAD has been successfully applied to the determination of SAs and PENs milk samples and synthetic urine solutions.

Deep residual network enabled smart hyperspectral image analysis and its application to monitoring moisture, size distribution and contents of four bioactive compounds of granules in the fluid-bed granulation process of Guanxinning tablets

Bed collapse is a serious problem in a fluid-bed granulation process of traditional Chinese medicine. Moisture content and size distribution are regarded as two pivotal influencing factors. Herein, a smart hyperspectral image analysis methodology was established via deep residual network (ResNet) algorithm, which was then applied to monitoring moisture content, size distribution and contents of four bioactive compounds of granules in the fluid-bed granulation process of Guanxinning tablets. First, a hyperspectral imaging camera was utilized to acquire hyperspectral images of 132 real granule samples in the spectral region of 389–1020 nm. Second, the moisture content and size distribution of the granules were measured with a laser particle sizer and a fast moisture analyzer, respectively. Moreover, the contents of danshensu, ferulic acid, rosmarinic acid and salvianolic acid B of the granules were determined by using high-performance liquid chromatography-diode array detection. Third, ResNet quantitative calibration models were built, which consisted of convolutional layer, maxpooling layer, four convolutional blocks with residual learning function and two fully connected layers. As a result, the Rc2 values for the moisture content, granule sizes and contents of four bioactive compounds are determined to be 0.957, 0.986, 0.936, 0.959, 0.937, 0.938, 0.956, 0.889, 0.914 and 0.928, whereas the Rp2 values are calculated as 0.940, 0.969, 0.904, 0.930, 0.925, 0.928, 0.896, 0.849, 0.844, and 0.905, respectively. The predicted values matched well with the measured values. These findings indicated that ResNet algorithm driven hyperspectral image analysis is feasible for monitoring both the physical and chemical properties of Guanxinning tablets at the same time.

Qualitative and quantitative phytochemicals of leaves, bark and roots of Antiaris toxicaria Lesch., a promising natural medicinal plant and source of pesticides

Antiaris toxicaria Lesch. of the Moraceae family is a tree that grows endemic to Indonesia and has a height of about 20-30 m. This study aimed to screen the phytochemical constituents of leaf, bark and its root. The plant materials were collected from the Samarinda Botanical Garden. Latex of this species in Indonesia is known as a source of blowpipe poison. In other countries Antiaris sp. plant parts (leaves, bark and seeds) are used in ethnobotany practice as raw material for traditional medicine. The leaves, bark and seeds of this plant are used in the treatment of syphilis, leprosy, cancer and used as laxatives for sore throats. Screening of the phytochemical constituents of the samples began by tracing the macromolecules of alkaloids, steroids, tannins, phenolic compounds, flavonoids and saponins with various tests. Alkaloids, saponins, tannins, phlobatnins, flavonoids and terpenoids were detected in the chemical analysis. High performance liquid chromatography diode array detection (HPLC-DAD) was conducted. HPLC screening of A. toxicaria extracts revealed the presence of galic acid, catechins, chlorogenic acid, caffeic acid, ellagic acid, epigallocatechin, routine, isoquercitrin, quercitrin, quercetin and kaempferol. The study revealed the array of secondary metabolites present in the plant that can be used in medicinal preparations and will be candidate species for developing a natural insecticide.

Identification of an anti-herpetic compound isolated from Pistacia vera L. male floral buds.

Due to the numerous side effects of conventional drugs against herpetic infections and the growing phenomenon of resistance, the researchers turned to natural compounds as a source of new drugs because they are less toxic than the synthetic molecules. This study aimed to analyse the activity of Pistacia vera L. male floral budextracts, against the replication of herpes simplex virus type 2, as well as to investigate their mode of action, isolate, and identify the active compound. Cell viability and anti-herpes virus activity were performed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and the plaque reduction assay, respectively. Three extracts (ethanolic, aqueous and polysaccharide extracts) were tested, only aqueous and polysaccharide extracts had anti-herpetic activity with a selectivity index of 29.12 and 20.25, respectively. Investigation about the mechanism of action indicated that the two active extracts inhibited the virus replication by direct contact with virucidal selectivity indexes of 39.15 and 32.09, respectively. An active compound was isolated from the aqueous extract using TLC bio-guided assay: it was identified as gallic acid by high-performance liquid chromatography-diode array detection coupled with electrospray ionization mass spectrometry (HPLC-DAD-ESI-MSn). The antiviral activity of Pistacia vera L. has been previously shown. The selectivity index of gallic acid is much lower than that of the active extract from which it has been isolated. Therefore, we can consider the aqueous extract prepared from Pistacia vera L. male floral buds as a promising natural product for treating herpetic diseases.

Magnetic solid phase extraction coupled with high-performance liquid chromatography-diode array detection based on assembled magnetic covalent organic frameworks for selective extraction and detection of microcystins in aquatic foods

It is crucially important to develop simple, selective, and rapid extraction pretreatments and analytical methods to detect microcystins (MCs) in food samples with complex matrices. In this study, a magnetic self-assembled covalent organic framework (COF) adsorbent was synthesized via a facile approach by using a one-pot reaction of 1,6-bis(4-formylphenyl)-3,8-bis(4-aminophenyl)pyrene (BFBAPy) as precursors to assemble amino-functionalized magnetic Fe3O4-NH2 nanoparticles (Fe3O4@Py-COF, simplified as mCOF). The superparamagnetic mCOF is found to exhibit a high specific surface area, abundant nanopores and good stability. In particular, adsorption experiments demonstrate that mCOF exhibits a good adsorption capability, efficiency and some specificity to MCs. The mCOF was applied for magnetic solid phase extraction (MSPE) of two kinds of MCs (MC-LR and MC-RR) from aquatic samples followed by high-performance liquid chromatography-diode array detection (HPLC-DAD). Under the optimized conditions, good linearity is obtained in the range of 10-1000 µg/kg (R2≥0.9989), the limits of detection are 3.0-4.5 µg/kg, and the relative standard deviations (RSDs) are lower than 4.9% (n=5). The extraction recoveries are also satisfactory (84.2%-105%). These results demonstrate that the developed method can be used as a good alternative method for the selective determination of MCs in complex aquatic foods.

The Uncertainty Profile Used for Full Validation of the HPLC Method to Determine 22 Azo Amines in Fabrics.

Azo dyes are synthetic dyes that can degrade to carcinogenic amines, therefore determining their exact concentration is crucial. The purpose of this study is to demonstrate that an HPLC method may be used to quantify 22 azo dye amines in a textile matrix. The HPLC-DAD (Diode Array Detector) technique for measuring 22 amines in a textile matrix was tested using a new graphical statistical strategy based on the building of β-content, γ-confidence tolerance intervals, which allows for good qualimetry of analytical procedures. In this way, we established the approach's ability to perform a full validation of the analytical technique as well as its ability to estimate measurement uncertainty in a simple and uncomplicated way with minimum effort, utilizing only the data collected during the analytical validation. The findings suggest that this technique can properly assess the validity of the HPLC method for simultaneous determination of 22 amines, with 67-90% of compliance results falling within acceptable limits. Using the uncertainty profile methodology, the full validation of an HPLC method for the determination of 22 azo amines in a textile matrix was successfully established. The development and evaluation of an efficient HPLC technique for the simultaneous determination of 22 azo amines in a textile matrix have been completed. The total reliability of the analytical procedure was established by evaluating its measurement uncertainty at each concentration level using the suggested uncertainty profile approach and confirming proportions 67 to 90% of compliance.

Integrative quantitative and qualitative analysis for the quality evaluation and monitoring of Danshen medicines from different sources using HPLC-DAD and NIR combined with chemometrics.

The root and rhizome of Salvia miltiorrhiza (Danshen in short) is a well-known herbal medicine used to treat cardiovascular diseases in the world. In China, the roots and rhizomes of several other Salvia species (Non-Danshen in short) are also used as this medicine in traditional folk medicine by local herbalists. Differences have been reported in these medicines originating from different sources, and their quality variation needs to be clearly investigated for effective clinical application. This study presented a comprehensive quality evaluation and monitoring for Danshen from 27 sampling sites and Non-Danshen from other 5 Salvia species based on a high-performance liquid chromatography-diode array detector (HPLC-DAD) and near-infrared (NIR), with the combination of chemometric models. The results showed that cryptotanshinone, tanshinone IIA, tanshinone I, salvianolic acid B, salvianic acid A sodium, dihydrotanshinone I, and rosmarinic acid in these medicines from different sources exhibited great variations. Referring to the standards in Chinese Pharmacopoeia (CP), European Pharmacopeia (EP), and United States Pharmacopeia (USP), Non-Danshen from S. brachyloma, S. castanea, S. trijuga, S. bowleyana, and S. przewalskii were assessed as unqualified, and Danshen in the Shandong Province had the best quality due to the high qualified rate. Based on random forest (RF) and partial least-squares discriminant analysis (PLS-DA), NIR technique could successfully monitor the quality of these medicines by discriminating the species and regions with the accuracies of 100.00 and 99.60%, respectively. Additionally, modified partial least-squares regression (MPLSR) models were successfully constructed to investigate the feasibility of NIR fingerprints for the prediction of the quality indicators in these medicines. The optimized models obtained the best results for the total of tanshinone IIA, tanshinone I, and cryptotanshinone (TTC), tanshinone IIA, and salvianolic acid B, with the relative prediction deviation (RPD) of 4.08, 3.92, and 2.46, respectively. In summary, this study demonstrated that HPLC-DAD and NIR techniques can complement each other and could be simultaneously applied for evaluating and monitoring the quality of Danshen medicines.

Application of Deep-Learning Algorithm Driven Intelligent Raman Spectroscopy Methodology to Quality Control in the Manufacturing Process of Guanxinning Tablets.

Coupled with the convolutional neural network (CNN), an intelligent Raman spectroscopy methodology for rapid quantitative analysis of four pharmacodynamic substances and soluble solid in the manufacture process of Guanxinning tablets was established. Raman spectra of 330 real samples were collected by a portable Raman spectrometer. The contents of danshensu, ferulic acid, rosmarinic acid, and salvianolic acid B were determined with high-performance liquid chromatography-diode array detection (HPLC-DAD), while the content of soluble solid was determined by using an oven-drying method. In the establishing of the CNN calibration model, the spectral characteristic bands were screened out by a competitive adaptive reweighted sampling (CARS) algorithm. The performance of the CNN model is evaluated by root mean square error of calibration (RMSEC), root mean square error of cross-validation (RMSECV), root mean square error of prediction (RMSEP), coefficient of determination of calibration (), coefficient of determination of cross-validation (), and coefficient of determination of validation (). The values for soluble solid, salvianolic acid B, danshensu, ferulic acid, and rosmarinic acid are 0.9415, 0.9246, 0.8458, 0.8667, and 0.8491, respectively. The established model was used for the analysis of three batches of unknown samples from the manufacturing process of Guanxinning tablets. As the results show, Raman spectroscopy is faster and more convenient than that of conventional methods, which is helpful for the implementation of process analysis technology (PAT) in the manufacturing process of Guanxinning tablets.

Rapid and Sensitive Determination of Polycyclic Aromatic Hydrocarbons in Green Tea Samples by Dispersive Liquid-Liquid Microextraction Coupled to High-Performance Liquid Chromatography-Diode Array Detection

A rapid and sensitive dispersive liquid-liquid microextraction (DLLME) has been developed for the extraction of selected polycyclic aromatic hydrocarbons (PAHs), namely phenanthrene (PHE) and fluoranthene (FLA) in green tea beverage samples. The extracted PAHs were separated and determined by using high-performance liquid chromatography diode array detection (HPLC-DAD). An experimental design using response surface methodology (RSM) and central composite design (CCD) was performed to evaluate the interactive effects of the 2 most significant parameters, namely extraction time and sample pH. The optimal conditions were sample pH of 6.5 with 1.25 min extraction time. The analysis of variance (ANOVA) showed that the most influential parameter was the extraction time. The predicted values were obtained in good agreement with the actual value (R2 ≥ 0.9086). Under the optimal extraction conditions, the method demonstrated acceptable linearity (R2 ≥ 0.9996) over a concentration range (10 - 1,000 µg L−1) for different PAHs. The limits of detection and quantifications were in the range of (4 - 10 µg L−1) and (18 - 50 µg L−1), respectively. Good analytes recovery (102 - 110 %) and excellent precision level with relative standard deviations (RSD %, n = 3) were obtained between 1.53 and 4.52 %. The method was successfully applied to the analysis of spiked green tea beverage samples. The proposed method is rapid, reliable, sensitive, and environmentally friendly for the detection of PAHs.&#x0D; HIGHLIGHTS&#x0D; &#x0D; A more efficient sample preparation method is required to measure interferences and enrich target analysis of PAHs residues in green tea, as existing methods are time-consuming, significant tendency to form emulsions, consume large volumes of solvents, and involve disposal of toxic or flammable chemicals&#x0D; Dispersive liquid-liquid microextraction (DLLME) method coupled with a high-performance liquid chromatography diode array detector (HPLC-DAD) was developed for the analysis of selective PAHs, namely fluoranthene (FLA) and phenanthrene (PHE) in green tea beverage samples&#x0D; RSM optimized DLLME parameters based on CCD, and the optimal conditions used during the analysis of PHE and FLA in the green tea samples extracted the non-polar PHE and FLA with good sensitivity. The procedure was simple, rapid, sensitive, and minimized the consumption of organic solvent&#x0D; &#x0D; GRAPHICAL ABSTRACT

"One-pot" preparation of aminated carbon nanotube-modified magnetic nanoparticles and their application to the quantification of phenoxyacetic acid herbicides in cereal and vegetable samples

有效萃取是分析复杂样品中苯氧羧酸类除草剂(PAs)残留的关键步骤。为此,该文利用“一锅法”水热技术快速、简便地制备了氨基碳纳米管功能化磁性纳米粒子(NH2-CNTs@M)并作为磁固相萃取(MSPE)的萃取介质,用于萃取谷物和蔬菜样品中痕量PAs。研究利用多种手段对NH2-CNTs@M的形貌、尺寸、磁性性质等进行了表征,结果表明Fe3O4的粒径、氨基化碳纳米管的直径以及NH2-CNTs@M的磁饱和值分别为30 nm、40 nm和44.2 emu/g。详细考察了制备条件和萃取参数对NH2-CNTs@M/MSPE萃取性能的影响,结果表明,NH2-CNTs@M/MSPE可通过π-π、疏水和氢键作用有效富集目标化合物,最佳萃取条件如下:吸附剂用量为30 mg,解吸溶剂为含2.0%(v/v)甲酸的乙腈溶液,吸附时间和解吸时间分别为8.0 min和3.0 min,基底pH值为6.0,不调节基底的离子强度。将NH2-CNTs@M/MSPE与高效液相色谱-二极管阵列检测技术(HPLC-DAD)联用,建立了谷物和蔬菜中PAs的灵敏检测方法。谷物和蔬菜基质中苯氧羧酸类除草剂的检出限(LOD, S/N=3)分别为0.32~1.6 μg/kg和0.53~1.6 μg/kg,定量限(LOQ, S/N=10)分别为0.94~4.8 μg/kg和1.6~4.8 μg/kg。在两种实际样品中不同浓度下的加标回收率分别为73.1%~112%和72.3%~113%。与现有方法相比,所建方法具有萃取速度快、灵敏度高和环境友好等特点。

Detection, isolation and identification of more bioactive compounds from Fusarium equiseti, an endophytic isolated from Ocimum gratissimum

Endophytes have continued to gain fame due to their ability to produce an array of secondary metabolites within the host system with huge untapped pharmacological potentials. This study was carried out to further identify and isolate novel therapeutic compounds from Fusarium equiseti, an Endophytic fungus isolated from leaves of Ocimum gratissimum. Endophytic fungal isolation, fungal fermentation, and extraction of secondary metabolites were carried out using standard laboratory methods. The crude extracts of Fusarium equiseti were subjected to further chromatographic techniques using vacuum liquid chromatography, Sephadex LH 20 and semipreparative HPLC for isolation of bioactive compounds. The fractions and the isolated compounds obtained were further subjected to high performance liquid chromatography-Diode Array Detector (HPLC-DAD). The analytical HPLC led to the further detection of many bioactive compounds namely: Enniatin A, Aureonitol, Serasinoside H1, Altenusin, Aplysinamisin, benzylnitril, ruspolinone and Orientin. Semipreparative HPLC led to the isolation of 6 pure compounds of which two were identified as benzylnitril, and ruspolinone. The remaining four were not identified due to lack of library hits. The detected and the isolated compounds have been previously shown to exhibit a wide array of biological activities including antiviral, antifungal, hepatoprotection, antibacterial, anticancer, cytotoxic, and antioxidant properties. The unidentified compounds may hold enormous potential as new bioactive lead compounds for development into novel therapeutic agents. Therefore, the Endophytic fungus, Fusarium equiseti should be harnessed for its potential pharmacological, pharmaceutical, agricultural and industrial applications.

Gender Discrimination of Flower Buds of Mature Populus tomentosa by HPLC Fingerprint Combined with Chemometrics.

A high performance liquid chromatography-diode array detector (HPLC-DAD) was used to establish the HPLC fingerprint. Chemometrics methods were used to discriminate against the gender of flower buds of Populus tomentosa based on areas of common peaks calibrated with the HPLC fingerprint. The score plot of principal component analysis (PCA) showed a clear grouping trend (R2X, 0.753; Q2, 0.564) between female and male samples. Two groups were also well discriminated with orthogonal partial least squares-discriminant analysis (OPLS-DA) (R2X, 0.741; R2Y, 0.980; Q2, 0.970). As the hierarchical clustering analysis (HCA) heatmap showed, all samples were separated into two groups. Four compounds were screened out by S-plot and variable importance in projection (VIP > 1.0). Two of them were identified as siebolside B and tremulacin. This study demonstrated that HPLC fingerprints combined with chemometrics can be applied to discriminate against dioecious plants and screen differences, providing a reference for identifying the gender of dioecious plants.

Facile synthesis of hypercrosslinked polymer as high-efficiency adsorbent for the enrichment of nitroimidazoles from water, honey and chicken meat

Design and fabrication of functionalized hypercrosslinked polymers (HCPs) for enhancing their performance by using green renewable monomers has attracted considerable research interest. In this study, hydroxyl‑functional HCP (labeled as OHHCP) was prepared via the knitting method by applying natural naringenin as a monomer for the first time. Due to the good hydrophilicity and strong H-bonding ability, the OHHCP showed high extraction capacity for nitroimidazoles. Thus, it was successfully applied as a potent adsorbent for solid phase extraction of five nitroimidazoles in water, honey and chicken meat, followed by high-performance liquid chromatography-diode array detector analysis. At the optimized conditions, the limit of detections (S/N = 3) of the proposed method for water, honey and chicken samples were 0.02 - 0.06 ng mL−1, 0.5 - 1.0 ng g−1 and 0.8 - 1.0 ng g−1, respectively. The recoveries were 80.0 - 110%, and the relative standard deviations were below 10.0%. The OHHCP also displayed good application prospects for other organic compounds with H-bonding capability. This study highlights the facile preparation of OH-functionalized HCPs from renewable and natural resources as potent adsorbents for polar compounds.