Performance Liquid Chromatography-diode Array Research Articles

Application of continuous magnetic solid phase extraction in the extraction of tetracycline antibiotics from honey samples

This study aimed to develop a continuous magnetic solid phase extraction method in a narrow bore tube for the extraction of tetracycline antibiotics from honey samples before their determination with high performance liquid chromatography–diode array detector. In this work, a magnetic covalent organic framework is used as the sorbent. The extraction method is performed in a narrow bore tube by adding 25 mg of a magnetic sorbent prepared from melamine, barbituric acid, and Fe3O4 into the diluted honey sample solution. By using a magnet, the sorbent is moved up and down through the narrow bore tube for five times to improve extraction efficiency. After adsorption the analytes, they are eluted from the sorbent surface using 2,2–dimethoxypropane under vortexing. Then, by using a magnet, the eluent containing the extracted analytes are taken and evaporated with continuous flow of nitrogen. Finally, the residue containing the enriched analytes is reconstituted in microliter–level of mobile phase and injected into chromatographic system for quantitative analysis. Based on the outcomes, the method demonstrated good linearity (0.37–1000 ng g−1), high enrichment factors (175–203), good extraction recoveries (70–81 %), low LODs (0.11–0.18 ng g−1) and LOQs (0.37–0.60 ng g−1). The proposed method is effectively applied for quantification of tetracyclines in twenty–four honey samples. Considering the results, none of the honey samples was contaminated with the studied antibiotics. Regarding to the above–mentioned analytical advantages of the proposed method, its simplicity and rapidity, and green synthesis of the magnetic sorbent particles, the suggested method can be used as a routine method for the extraction of tetracyclines from honey samples.

Expression analysis of transcription factor (CBF/DREB) gene and biochemical response of Cannabis sativa to cadmium toxicity and foliar application of molybdenum

Plants respond to heavy metals stress by the activation of stress responsive genes to establish biochemical defense mechanisms against the stress. We have investigated the molecular and biochemical response of Cannabis sativa to cadmium (Cd) stress in the presence of molybdenum (Mo) foliar treatments. For this purpose, C. sativa plants were allowed to grow in pots containing Cd polluted soil, for two month duration. Aqueous solutions of ammonium molybdate pentahydrate (0.5, 1.0 and 2.0 ppm) were foliarly sprayed on the plants, at two weeks intervals. Various parameters were inter-correlated i.e., Plant biomass, Cd phyto-accumulation, transcript level/expression of CBF/DREB genes, concentrations of free proline, polyphenolics, and chlorophyll contents. Phenolic compounds were analyzed by High Performance Liquid Chromatography Diode Array Detector (HPLC-DAD) and Cd contents were analyzed by Atomic Absorption Spectrophotometer. Biomass and chlorophyll contents decreased while the concentrations of free proline and polyphenolics increased under Cd stress. Dry biomass of the all the plant parts (roots (1.87 ± 0.22 g), stem (3.28 ± 0.39 g) and leaves (3.54 ± 0.87 g) and free proline in roots (69.00 ± 8.28 µg/g) and leaves (40.56 ± 4.87 µg/g) were most significantly increased with foliar spray of 2.00 ppm Mo. Nineteen (19) different polyphenolic compounds were identified and quantified in leaves and most of them were highly increased in concentration under Cd stress. The highest concentration was noted in Caffeoyl tyramine (1111 µg/g) in plants treated with 2.00 ppm Mo. Transcript level of CBF/DREB genes in control plants were less as compared to Mo treated plants, where a high increase in transcript level of these genes were found. Expression of CBF /DREB genes showed significant positive correlations with Cd accumulation (R2= 0.751) and concentrations of free proline (R2 = 0.62) and polyphenolics (R2 = 0.65) in leaves. The results suggested that Mo increased the expression of CBF/DREB genes and subsequently the concentration of phenolic compounds and free proline to combat plant against the toxicity of high concentration of Cd on plants.

Fast surface floating organic droplets based dispersive liquid‐liquid microextraction for trace enrichment of multiclass pesticide residues from different fruit juice samples followed by high performance liquid chromatography–diode array detection analysis

AbstractThis study was designed to enable the development of a simple, fast, and environmentally friendly analytical technique utilizing dispersive liquid‐liquid microextraction based on surface floating organic droplets for selective and quantitative enrichment of trace level pesticide contaminants from different fruit juice samples for subsequent detection by high performance liquid chromatography, combined with a diode array detector. The selective extraction was necessitated in order to isolate the seven multiclass pesticide residues frequently occurring in fruit juice samples. The effects of experimental parameters such as pH of sample solution, type and volume of extraction and dispersive solvents, ionic strength and extraction time were optimized. The optimized method was validated using spiked blank sample and satisfactory results for accuracy, with recoveries ranging from 87.23% to 99.45%, with %relative standard deviation between 1.37 and 8.39, precision in terms of %relative standard deviation ≤ 10.78 and linearity at concentration levels from 3 to 1500 ng/ml, which corresponded with correlation coefficients ≥ 0.998. The limits of detection and the limits of quantification were ranged from 1.3×10−2 to 5.3×10−2 and 4.2×10−2 to 1.8×10−1 μg/L, respectively. At the end, the method was successfully applied to analyze real fruit juice samples and target analytes were not detected in real samples.

Screening of secondary metabolites produced by a mangroove-derived Nigrospora species an endophytic fungus isolated from Rhizophora racemosa for antioxidant and antimicrobial properties

Marine fungi have shown large chemo-diversity of unharnessed important secondary metabolites required for drug development. In this study, endophytic fungi Nigrospora species (5S3) was isolated from the fresh stem of Rhizophora racemosa from a mangrove forest in Lagos Nigeria and axenic colonies were fermented on sterile rice medium for 21 days. The antimicrobial and antioxidant activities of the extract were evaluated. Chemical analyses such as High Performance Liquid Chromatography Diode Array Detector (HPLC-DAD) and Nuclear magnetic Resonance Imaging (NMR) analyses of selected Vacuum Liquid Chromatography (VLC) fractions revealed the presence of ten known compounds with established biological activities. Tested fractions of the extract exhibited antimicrobial activities against at least one Gram positive and Gram negative bacteria with MIC values that ranged between 0.13 to 1 mg/mL. FE2 and FE3 fractions of the extract demonstrated poor antioxidant activity of less than 10%. Septicine, Aureonitol, Papuamine, Di-iso-octylphtalat, 1-(2,4 Dihydroxy-3,5-Dimethylphenyl)-Ethanone, Cladosporin, Tetrabenzofuran, Dihydrophthalate, 9-Octadecaenoic acid and Eicosane were the compounds detected in the extracts. Our findings reveal that Nigrospora spp an endophytic fungi possesses unique chemo diversity of bioactive secondary metabolites that could be utilized for development of new drugs.

Carotenoids Composition of Green Algae Caulerpa racemosa and Their Antidiabetic, Anti-Obesity, Antioxidant, and Anti-Inflammatory Properties.

Green alga Caulerpa racemosa is an underexploited species of macroalgae, even though it is characterized by a green color that indicates an abundance of bioactive pigments, such as chlorophyll and possibly xanthophyll. Unlike chlorophyll, which has been well explored, the composition of the carotenoids of C. racemosa and its biological activities have not been reported. Therefore, this study aims to look at the carotenoid profile and composition of C. racemose and determine their biological activities, which include antidiabetic, anti-obesity, anti-oxidative, anti-inflammatory, and cytotoxicity in vitro. The detected carotenoids were all xanthophylls, which included fucoxanthin, lutein, astaxanthin, canthaxanthin, zeaxanthin, β-carotene, and β-cryptoxanthin based on orbitrap-mass spectrometry (MS) and a rapid ultra-high performance liquid chromatography (UHPLC) diode array detector. Of the seven carotenoids observed, it should be highlighted that β-carotene and canthaxanthin were the two most dominant carotenoids present in C. racemosa. Interestingly, the carotenoid extract of C. racemosa has good biological activity in inhibiting α-glucosidase, α-amylase, DPPH and ABTS, and the TNF-α and mTOR, as well as upregulating the AMPK, which makes it a drug candidate or functional antidiabetic food, a very promising anti-obesity and anti-inflammatory. More interestingly, the cytotoxicity value of the carotenoid extract of C. racemosa shows a level of safety in normal cells, which makes it a potential for the further development of nutraceuticals and pharmaceuticals.

Magnet Integrated Fabric Phase Sorptive Extraction for the Extraction of Resin Monomers from Human Urine Prior to HPLC Analysis

In this work, a method for the simultaneous determination of four resin monomers: Bisphenol A, bisphenol A methacrylate glycidate, triethyleneglycol-dimethacrylate, and urethane dimethacrylate, from human urine using magnet integrated fabric phase sorptive extraction (MI-FPSE), followed by high performance liquid chromatography (HPLC) diode array detection (HPLC-DAD), is presented. MI-FPSE is a novel configuration of FPSE that incorporates the stirring and extraction mechanism into one device, resulting in an improved extraction kinetic factor. FPSE is a green sample preparation technique that uses a flexible surface, such as cellulose, coated with a polymeric material using sol–gel technology. Poly(tetrahydrofuran) (PTHF) material was selected, due to its higher efficiency in terms of recovery rate among the studied MI-FPSE membranes. Optimization of the extraction process was performed based on several extraction and elution parameters. The method was validated for its linearity, selectivity, accuracy, precision, and stability of the samples. For the four compounds, the LOD and LOQ were 0.170 ng/μL and 0.050 ng/μL, respectively. The relative standard deviation of the method was less than 9.8% and 11.9%, for the within-day and between-day precision, respectively. The relative recoveries were between 85.6 and 105.2% in all cases, showing a good accuracy. The effectiveness of the proposed method was confirmed through successful application to the bioanalysis of real urine samples.

Dispersive Liquid - Liquid Micro extraction Technique Coupled with High Performance Liquid Chromatography Diode Array Detector for the Determination of Sulfonamides in Water Samples

A dispersive liquid-liquid microextraction combined with high-performance liquid chromatography with diode array detection (DLLME-HPLC-DAD) has been developed for the determination of 15 sulfonamides in water samples. The effects of experimental parameters on the performance of the method such as the type and volume of extraction and disperser solvents, pH of the solution, effect of salt, and centrifugation time were evaluated, and optimum conditions were established. Under these optimum conditions, linearity was found in the range of 2 - 1 000 μg L-1 with regression coefficients better than 0.9990. The limit of detection (LOD) and limit of quantification (LOQ) values were in the range of 0.6 - 7.8 μg L-1 and 1.5 - 8.3 µg L-1, respectively. Intra-day and inter-day precision ranged from 1.5 - 9.7% and from 3.1 - 9.9%, respectively. The accuracy of the method were also evaluated in samples from three different sources of water (river water, groundwater, and tap water) were found to range from 70.5 to 103.9% with %RSD values ranging from 0.5 to 9.8%, with the exception of sulfaguanidine in river water and groundwater where the percentage recovery ranged from 54.3 - 84.9% at the two higher concentration levels (100 and 400 µg L-1).Furthermore, the effect of sample matrix on the extraction of target compounds was evaluated using the relative recovery (%RR) of the samples from three different water sources relative to the ultrahigh purity (UHP) water sample spiked with target analytes, and found in the range of 70.3 - 106.1%.The proposed method was successfully applied to wastewater treatment plant samples and Sulfisoxazole (SSO) was detected in the influent samples in the range of 14.8 - 17.8 µg L-1 with corresponding %RSD, (n = 5) value of 1.6% to 1.9%.The results indicated that the proposed method is effective for the extraction and determination of the sulfonamides in water samples.

GC-MS and LC-DAD-MS Phytochemical Profiling for Characterization of Three Native Salvia Taxa from Eastern Mediterranean with Antiglycation Properties.

Salvia fruticosa and S. pomifera subsp. calycina are native to Eastern Mediterranean and S. pomifera subsp. pomifera is endemic to Greece. The primary aim of this study was to develop an analytical methodology for metabolomic profiling and to study their efficacy in combating glycation, the major biochemical complication of diabetes. After sequential ultrasound-assisted extraction of 2 g of leaves with petroleum ether and 70% methanol, the volatile metabolites in the petroleum ether extracts were studied with GC-MS (Gas Chromatography-Mass Spectrometry), whereas the polar metabolites in the hydroalcoholic extracts were determined and quantified by UHPLC-DAD-ESI-MS (Ultra-High Performance Liquid Chromatography-Diode Array Detector-Mass Spectrometry). This methodology was applied to five populations belonging to the three native taxa. 1,8-Cineole was the predominant volatile (34.8-39.0%) in S. fruticosa, while S. pomifera had a greater content of α-thujone (19.7-41.0%) and β-thujone (6.0-39.1%). Principal Component Analysis (PCA) analysis of the volatiles could discriminate the different taxa. UHPLC-DAD-ESI-MS demonstrated the presence of 50 compounds, twenty of which were quantified. PCA revealed that not only the taxa but also the populations of S. pomifera subsp. pomifera could be differentiated. All Salvia samples inhibited advanced glycation end-product formation in a bovine serum albumin/2-deoxyribose assay; rosmarinic and carnosic acid shared this activity. This study demonstrates the antiglycation activity of S. fruticosa and S. pomifera extracts for the first time and presents a miniaturized methodology for their metabolomic profiling, which could aid chemotaxonomic studies and serve as a tool for their authentication and quality control.

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.

Combination of mixed mode dispersive solid phase extraction with magnetic ionic liquids based dispersive liquid–liquid microextraction for the extraction of anticoagulant drugs from urine samples

In this report, combination of a mixed mode dispersive solid phase extraction with dispersive liquid–liquid microextraction has been performed in order to the effective isolation of three anticoagulant drugs (anagrelide, betrixaban, and apixaban) from urine sample. The extracted drugs were quantified by high performance liquid chromatography–diode array detector. Firstly, analytes were adsorbed onto a mixture of octadecylsilane, graphitized carbon black, and primary secondary amine sorbents which their composition was obtained by a simplex centroid design. To increase the adsorption efficiency, sonication of the solution and sorbents mixture was performed. The loaded analytes onto the sorbent surface were washed employing a water–miscible organic solvent which was utilized as a disperser in microextraction process. The microextraction step was done using a magnetic ionic liquid (as an extractant) and the droplets were sedimented at the bottom of tube with the aid of an external magnetic field. Satisfactory analytical results such as wide linear ranges (0.21–250 µg/L), high enrichment factors (223–247) and extraction recoveries (76–84 %), and low limits of detection (0.04–0.06 µg/L) and quantification (0.16–0.21 µg/L) were obtained using the optimum experimental situations. Lastly, the offered procedure was utilized for the quantification of the opted analytes in urine samples.

Comprehensive quality consistency evaluation strategy and analysis of compound danshen tablet

The compositions of traditional Chinese medicines are extremely complex,as a result, exploring consistent quality is demanded and challenging. Quality consistency of products obtained from the same manufacturer has received little attention. The strategy of quality consistency evaluation (QCE) has been proposed as a novel method for quality control of Traditional Chinese Medicine Patent Prescription (TCMPP). This study aimed to establish a comprehensive QCE strategy for Compound Danshen Tablet (CDT). High Performance Liquid Chromatography–Diode Array Detector and Gas Chromatography–Mass Spectrometry were separately applied to determinate the content of seven and two index components, which representing the quality actuality of different raw medicines. The dissolution test was designed to obtain the dissolution ratios of CDT samples. QCE can provide the intra–batch content consistency difference (PA), inter–batch content consistency difference (PB), and dissolution ratio consistency difference (PR) values. The consistency of CDT samples from 15 different manufacturers (75 batches) was evaluated by principal component analysis (PCA), which showed that the total content (nine index components) of the 75 batches of samples obtained from 15 manufacturers ranged from 22.11 to 38.45 mg·tablet−1. The dissolution ratios ranged from 74.8% to 116.4%. The PA values of 15 manufacturers ranged from 2.4% to 12.2%, and the PB (11.1–45.1%) values were higher than the PA values. The PR values reflecting the various dissolution ratios in vitro ranged from 8.1% to 57.5%. The three consistency factors were ranked by PCA, and products of the 15 manufacturers were classified into three categories. The PA, PB, and PR values provided a comprehensive and effective approach for monitoring the quality consistency of CDT and can serve as an example of QCE for other TCMPP.

Nickel(II) interactions with chlorophylls in solution: impact to degradation induced by UV-irradiation

Chlorophylls and metal substituted complexes of chlorophylls with known photosensitizing abilities can be used in many types of biological and solar energy applications; thus, it is important to analyze their basic properties when they are treated by visible light and/or UV radiation. Nickel(II) can replace central magnesium from chlorophyll (Chl) molecule to form a metal substituted, “central” Ni-Chl complex. So, the possible formation of nickel-chlorophyll complexes in 95% ethanol at 40 °C was studied by UHPLC-DAD chromatography (UltraHigh Performance Liquid Chromatography–Diode Array Detector). Nickel(II)-chlorophylls interactions in the reaction solutions at 40 °C lead not only to the formation of the Ni-related Chls, Ni-Chl complexes but several oxidation and demetalation products of chlorophylls. On the other hand, the influence of nickel(II) – chlorophyll interactions on chlorophylls solutions stability under continual UV-A, -B, and -C irradiation in 95% ethanol, was followed by UV-Vis spectrophotometry. Chlorophylls as well as their reaction solutions with nickel(II) undergo photochemical degradation obeying first- order kinetics. In general, the degradation is “energy-dependent”, i.e. proportional to the UV photons energy input. Chlorophylls are less stable than their reaction solutions with nickel(II), probably due to the higher stability of Ni-chlorophylls complexes, to all three subranges of UV- irradiation.

Evaluation of the antioxidant potentials of extract and fractions of Vitex doniana fruit and identification of the bioactive metabolites using HPLC-DAD-MS analysis

Isoflavones and flavonoids in general found in fruits and vegetable act as natural antioxidants. This study was aimed at screening the isoflavone-rich fractions of Vitex doniana fruit extract for antioxidant activity using in vitro and in vivo models. The ethyl acetate and butanol fractions were screened for in vitro antioxidant activity by DPPH free radical scavenging and FRAP (Fe3+ Reducing Antioxidant Power) assays using ascorbic acid as standard. In vivo antioxidant activity was also tested against carbon tetrachloride-induced toxicity in mice using carbon tetrachloride (4 mL/kg) and silymarin (100 mg/kg) as standard. The ethyl acetate fraction and butanol Vacuum Liquid Chromatography (VLC) sub-fractions were subjected to High Performance Liquid Chromatography–Diode Array Detector (HPLC-DAD) and Liquid Chromatography-Mass Spectrometry (LC-MS) analyses. The ethyl acetate and butanol fractions inhibited DPPH radicals with an IC50 of 897 µg/mL and 2809.38 µg/mL respectively. Both fractions also showed mild FRAP result with EC50 of 1401 µg/mL and 7051 µg/mL respectively. The fractions produced significant decrease (P < 0.05) in ALP levels only while ethyl acetate fraction caused a significant reduction in the value of only malondialdehyde. Both fractions also increased levels of superoxide dismutase (SOD). HPLC-DAD analysis led to the detection of cinnamic acid, protocatechuic acid and two isoflavones daidzein and genistein. Further LC-MS analysis confirmed the presence of the isoflavones tectorigenin, 5-O-methylgenistein, and 5-O-methyltectorigenin, among other flavonoids, peonidin, 5-methylpeonidin, methylmalvidin and kaempferol-3-O-(2''galloyl)-glucopyranoside. The detected isoflavones and other flavonoids may contribute to the observed mild in vitro and good in vivo antioxidant activity of V. doniana fruit extract and fractions.

Seasonal Variation of Phytochemicals in Four Selected Medicinal Plants

Pharmacognosy Research,2021,13,4,218-226.DOI:10.5530/pres.13.4.14Published:October 2021Type:Original ArticleAuthors:Bonface Mwamatope, David Tembo, Elizabeth Kampira, Cecilia Maliwichi-Nyirenda, and Victoria Ndolo Author(s) affiliations:Bonface Mwamatope1, David Tembo2,*, Elizabeth Kampira3, Cecilia Maliwichi-Nyirenda4, Victoria Ndolo5 1Biomedical Sciences Department, College of Medicine, University of Malawi, Blantyre, MALAWI. 2Physics and Biochemical Sciences Department, The Polytechnic, University of Malawi, Blantyre, MALAWI. 3Medical Laboratory Department, College of Medicine, University of Malawi. 4Research Support Centre, College of Medicine, University of Malawi, Blantyre, MALAWI. 5Department of Human Ecology, Faculty of Science, Chancellor College, University of Malawi, Blantyre, MALAWI. Abstract:Background: The study aimed at assessing total alkaloids content (TAC), total flavonoids content (TFC), total phenolic content (TPC), antioxidant activity (AA) and predominant individual phenolic compounds in methanol extracts of M. oleifera, S.singueana, M.azedarach leaves and stem barks of L. discolor collected during different seasons of the year. Materials and Methods: TPC, TFC and TAC were analyzed using the Folin Ciocalteau assay, aluminum chloride assay and bromocresol green assay, respectively. 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) techniques were used to analyse AA. Phenolic compounds; Vanillic acid, (+)-catechin, quercetin, rutin, sinapic acid, 2,4-hydroxybenzoic acid and ferulic acid were analyzed using high performance liquid chromatography diode array detector (HPLC - DAD). Results: Barks of L. discolour exhibited high levels of TPC, TFC, TAC and AA during hot-dry season (summer) as compared to S. singueana, M. oleifera and M. azedarach leaves which showed significantly (p< 0.05) higher levels in hot-wet season (rainy). Levels of TPC, TFC and TAC were significantly (p< 0.05) influenced by seasonal variations and correlated with levels of AA. Profiles of all phenolic compounds analyzed were not similar in terms of chemical composition and concentration during different seasons. Sinapic acid and 2,4-hydroxybenzoic acid were predominant in S. singueana while sinapic acid and ferulic acid were predominant in M. oleifera. Vanillic acid and 2,4-hydroxybenzoic acid were predominant in L. discolor and M. azedarach respectively. Conclusion: The phytochemical constituents in medicinal plants are subject to seasonal variations which in turn influence the optimum season of harvesting. Keywords:Alkaloids, Antioxidant activity, Flavonoids, Medicinal plants, Phenolic compounds, Seasonal variationsView:PDF (984.49 KB)

Secondary metabolic profiles and anticancer actions from fruit extracts of immature pomegranates.

Immature fruits from Punica granatum L. thinning are a neglected side product of pomegranate production with cumbersome disposal costs for farmers. To explore value potential of immature fruits from pomegranate ‘Wonderful’ cultivars, the compositional landscapes and antitumorigenic activities of pomegranate extracts from two different stages of maturation were assessed. Cancer cell proliferation and cytotoxicity was quantified in human lung H1299 and colon HCT116 adenocarcinomas by crystal violet staining, MTS assay and caspase-3 activity. High performance liquid chromatography—diode array detector (HPLC/DAD) and high performance liquid chromatography—electrospray ionization—mass spectrometry (HPLC/ESI-MS) analyses indicate that immature fruits are rich sources of gallotannins and ellagitannins, with the highest amounts contained in immature fruit peels. Biological investigations reveal a robust anticancer activity by those immature P. granatum fruit extracts, which reflected induction of tumor cytotoxicity and cell death mechanisms. Together, present observations suggest P. granatum byproducts from the thinning process may provide unexplored values for virtuous circular economy.

Development of a deep eutectic solvent-based ultrasound-assisted homogenous liquid-liquid microextraction method for simultaneous extraction of daclatasvir and sofosbuvir from urine samples

An ultrasound-assisted homogenous liquid–liquid microextraction method using a new deep eutectic solvent was proposed for the extraction of daclatasvir and sofosbuvir from urine. The analytes were determined by high performance liquid chromatography–diode array detector. The deep eutectic solvent was prepared by mixing p-aminophenol with tetrabutyl ammonium chloride. It was used in the extraction procedure as an extraction solvent. The amine group in structure of the prepared deep eutectic solvent led to its various solubility in different pHs. In this method, urine sample was placed in a glass test tube and then mixed with sodium chloride and its temperature adjusted at 50 °C. Then, the deep eutectic solvent was dissolved in the solution by manually shaking. In the following, an ammonia solution was added to the solution and the mixture was sonicated for 4 min. After centrifugation, an aliquat of the sedimented phase was injected into the determination system. Low limits of detection (daclatasvir 1.0 and sofosbuvir 1.3 μg/L) and quantification (daclatasvir 3.3 and sofosbuvir 4.0 μg/L), high enrichment factor (daclatasvir 96 and sofosbuvir 90) and extraction recovery (daclatasvir 96 and sofosbuvir 90 %), and good percision (relative standard deviation ≤9.3 %) were obtained. The introduced method was successfully applied in the determination of daclatasvir and sofosbuvir concentrations in urine samples.

Exploring the transition from natural to synthetic dyes in the production of 19th-century Central Asian ikat textiles

This study focuses on the dye analysis of 26 ikat textiles present in the collection of the Arthur M. Sackler Gallery and originally collected by Dr. Guido Goldman with the aim to gain additional information about their provenance and dating. The investigation exploits the full potential of a multi-analytical approach, starting with a non-invasive survey of all the colors using fiber optic reflectance spectroscopy (FORS), which revealed the presence of indigo and insect-based red dyes. These data were used to select areas from which samples were taken and analyzed by high performance liquid chromatography diode array detector (HPLC–DAD). These results enabled most of the natural sources of dyes to be fully identified, including American cochineal (Dactylopius coccus), madder (probably Rubia tinctorum), lac (probably Kerria lacca), larkspur (Delphinum semibarbatum), pagoda tree flower buds (Sophora japonica), grape vine leaves (Vitis vinifera), indigo and tannins. Complex mixtures of dyes were present in most samples, as a result of both the ikat making process itself and traditional dyeing practices. Synthetic dyes were identified in 9 of the textiles. Samples were re-analyzed using HPLC–DAD coupled to mass spectrometry (HPLC–DAD-MS). Malachite green (basic green 4, C.I. 42000), fuchsine (basic violet 14, C.I. 42510), rhodamine B (basic violet 10, C.I. 45170) and methyl violet (basic violet 1, C.I. 42535) were identified, and a few other tentatively identified synthetic dyes (probably orange I, II and IV, rhodamine 6G, patent blue V and alizarin yellow GG) were detected. As the first synthesis of early synthetic dyes is well documented, their presence was used to refine the dating of these textiles. The contextualization of the results also appeared to support the stylistic assumption that more intricate and colorful designs with a higher level of complexity are dated earlier than simpler, larger and more graphic ones. The overall information acquired reveals a dynamic scenario and an interesting window into the dyers’ experiments and adjustments to the economic and technological changes of the nineteenth century.

Ultrasound-Vortex-Assisted Dispersive Liquid-Liquid Microextraction Combined with High Performance Liquid Chromatography-Diode Array Detection for Determining UV Filters in Cosmetics and the Human Stratum Corneum.

This study explores the amounts of common chemical ultraviolet (UV) filters (i.e., avobenzone, bemotrizinol, ethylhexyl triazone, octocrylene, and octyl methoxycinnamate) in cosmetics and the human stratum corneum. An ultrasound–vortex-assisted dispersive liquid–liquid microextraction (US–VA–DLLME) method with a high-performance liquid chromatography–diode array detector was used to analyze UV filters. A bio-derived solvent (i.e., anisole) was used as the extractant in the US–VA–DLLME procedure, along with methanol as the dispersant, a vortexing time of 4 min, and ultrasonication for 3 min. The mass-transfer rate of the extraction process was enhanced due to vortex-ultrasound combination. Various C18 end-capped columns were used to investigate the separation characteristics of the UV filters, with XBridge BEH or CORTECS selected as the separation column. Calibration curves were constructed in the 0.05–5 μg/mL (all filters except octocrylene) and 0.1–10 μg/mL (octocrylene) ranges, and excellent analytical linearities with coefficients of determination (r2) above 0.998. The developed method was successfully used to analyze sunscreen. Moreover, experiments were designed to simulate the sunscreen-usage habits of consumers, and the cup method was used to extract UV filters from the human stratum corneum. The results suggest that a makeup remover should be employed to remove water-in-oil sunscreens from skin.

Development and Validation of a Simple and Rapid HPLC Method for the Evaluation of Pesticide Residues in Plasma Samples of Farmers; Application in Toxicological and Risk Assessment Studies

Background: In the present work, an analytical method based on high performance liquid chromatography–diode array detection has been reported to evaluate the presence of some widely used pesticides in plasma samples of the farmers exposed to the pesticides in farm lands and rural zones. Prior to instrumental analysis, the analytes are extracted using a two–step extraction procedure based on a combination of cold–induced homogenous liquid–liquid extraction and dispersive liquid–liquid microextraction. Methods: In this method, initially acetonitrile is added to a tube containing the plasma sample and the mixture is vortexed. By this action, the proteins of plasma are precipitated at the bottom of the tube after centrifugation and a homogenous solution is collected on them. Subsequently, the mixture is placed in liquid nitrogen for a few seconds to freeze the aqueous phase. As a result, the homogenous state is broken and the analytes are extracted into the supernatant organic phase (acetonitrile), which is subsequently removed and used in the following microextraction method. Results: Under the optimum extraction conditions, the proposed method indicated good extraction recoveries (59–80%), satisfactory repeatability (relative standard deviation ≤ 6% for intra– and inter–day precisions), and low limits of detection (1.4–2.3 μg L−1). Conclusion: Finally, various plasma samples of the farmers were analyzed by the introduced method. Ease of operation, being environmentally friendly, rapidity, and low cost can be the main advantages of the introduced approach.

Simultaneous analysis of thirteen phytohormones in fruits and vegetables by SPE-HPLC-DAD.

Determination of phytohormones have attracted increasing attentions in food safety field. In this study, an efficient and quantitative method was developed which can simultaneously determinate thirteen phytohormones in fruits and vegetables using solid phase extraction (SPE) combined with high performance liquid chromatography-diode array detection (HPLC-DAD). The samples were extracted with 80% methanol containing 0.5% (V/V) formic acid, and the extracts were then concentrated and purified using primary secondary amine (PSA) and C18 tandem dual SPE cartridges. The analytes were separated on a Waters XBridge™ C18 column and eluated utilizing a gradient elution program of water and methanol. Mean recoveries of the thirteen analytes varied from 74.69 to 92.40%, with relative standard deviations < 3.57%. The limits of detection and quantitation were 0.005-0.018mg/kg and 0.02-0.10mg/kg, respectively. The phytohormones in kiwi fruit, strawberry, bean sprout, and green pepper were detected using the above method, respectively. Only the IAA content of 0.14mg/kg was detected for the strawberry from a supermarket, which was lower than the prescribed limit in food safety standards (0.2mg/kg).