Mixture Of Hexane Research Articles

Polarity Gradient Solvent Confinement Membrane Cartridge to Broaden Metabolite Coverage of Plasma Untargeted Analysis.

Various polarity chemicals exist in complex samples, such as plasma; nontargeted comprehensive analysis naturally requires multiple polar-extracted solvents; consequently, the polarity of the solvent plays a crucial role in the extraction efficiency of analytes from complex samples. In the present study, based on the diffusion behavior and nanoconfinement effect of solvents in the nanoconfined space, the polarity gradient solvent confinement liquid-phase nanoextraction (PGSC-NLPNE) protocol aimed to perform a one-step nontargeted analysis of a wide range of metabolites in plasma was established. The continuously wide range of extracted solvent polarities on carbon nanofibers/carbon fiber (CNFs/CF) membranes was achieved using a mixture of hexane, dichloromethane, methanol, and water as nanoconfined solvents. The polarities (Log P) of gradient solvents ranged from -1.38 to 3.94. Correlational analyses indicated that metabolites with Log P values ranging from -1.90 to 3.84 were closely related according to similarity-intermiscibility theory. Coupled with a homemade modified guard column device, CNFs/CF membrane cartridge (CCMC), a PGSC-NLPNE-UHPLC-MS online protocol was established and applied in plasma untargeted analysis. By comparing metabolome coverage, reproducibility, and extraction recovery with protein precipitation and two-step liquid-liquid extraction commonly used in untargeted analysis, the PGSC-NLPNE-CCMC protocol demonstrated higher reproducibility and recovery. This protocol has shown great potential for ultrafast analysis of plasma untargeted metabolomics with broader metabolome coverage. It could be a potential tool to rapidly screen out valuable biomarkers related to diseases in the clinic.

Durably Superhydrophobic Magnetic Cobalt Ferrites for Highly Efficient Oil-Water Separation and Fast Microplastic Removal.

Microplastic pollution has become a primary global concern in the 21st century. Recyclable magnetic particles with micro-nanostructures are considered an efficient and economical way to remove microplastics from water. In this study, superhydrophobic magnetic cobalt ferrite particles were prepared by using a simple coprecipitation method combined with surface functionalization. The micromorphology, chemical composition, hysteresis loop, and surface contact angle of the functionalized cobalt ferrite were characterized. The separation efficiency and absorption capacity of cobalt ferrite particles in water-oil separation and microplastic removal were investigated. The results showed that the saturation magnetic field intensity of cobalt ferrite was 65.52 emu/g, the residual magnetization intensity (Mr) was 18.79 emu/g, and the low coercivity was 799.83 Oe. Cobalt ferrites had stable superhydrophobicity in the pH range of 1-13. The separation efficiency of cobalt ferrite powder for four oil-water mixture separations was higher than 94.2%. The separation efficiency was as high as 99.6% in the separation of the hexane and water mixtures. Due to the synergistic effect of the hydrophobic effect and van der Waals force, the functionalized magnetic cobalt ferrite had a high and stable microplastic removal efficiency and capture capacity. The removal efficiency of microplastics was close to 100%, and the capture capacity was 2.56 g/g. After ten microplastic removal cycles, the removal efficiency reached more than 98%, and the surface contact angle was still greater than 150°.

Studying the Characteristics of Tank Oil Sludge

Oil sludge is one of the main pollutants generated by the oil industry. Due to serious pollution and increasing oil production, problems arise every year in the effective treatment of oil sludge. The current study examines the composition and physicochemical characteristics of oil sludge, as well as traditional and new methods for processing oil sludge. With the tightening of environmental protection requirements, oil sludge quality reduction, recycling, and harmless treatment technologies will become necessary in the future. The primary task was to determine the composition of tank oil sludge, separate it from mechanical impurities, and study the influence of ultrasonic treatment and subsequent atmospheric distillation on the extract. The separation of the concentrate and the composition of the tank oil sludge, using an extracted mixture of hexane and benzene, are considered. The use of modern SEM methods, elemental analysis, NMR analysis, IR, ultrasound, and GC–mass spectrometry made it possible to characterize the organic part of reservoir oil sludge and its distillation products. First, 300 g of tank oil sludge was preheated and mixed with 300 mL of solvent (hexane:benzene = 1:1). After mixing with the solvent, the result mixture was filtered. Then, it was placed in an ultrasonic bath and exposed to ultrasound at a frequency of 100 kHz for 30 min. After processing, it was extracted in a Soxhlet apparatus at a temperature of 65 °C to isolate the extract. The resulting extract was analyzed on a gas chromatograph with mass detection. The composition of the extract was as follows (in %): hexane—83.99; total hydrocarbon isomers—7.12; n-hydrocarbons—2.52; benzene—6.37%. At a temperature of 85 °C, the benzene yield was 65.85%. It has been established that the fractions obtained through the distillation of oil sludge at temperatures of 65–85 °C have improved dissolving capacity. It has also been shown that the use of these fractions promotes an increase in the content of hydrocarbon isomers by 12–13% in the extract composition.

Humidity-induced aragonite formation from amorphous calcium carbonate (ACC) with addition of n-butylamine

Direct conversion from amorphous calcium carbonate (ACC) to aragonite has been extremely difficult compared to the other two polymorphs, calcite and vaterite. In the present study, aragonite formation with a high polymorph fraction (>97 %) was achieved from ACC immersed in n-butylamine under 90 % RH (relative humidity) at 30 °C for 2 h. It is noteworthy that aragonite with a high polymorphic fraction was obtained without the addition of Mg2+ ion, which is well known to promote aragonite formation.To understand the effects of hydrophobic and basic properties of n-butylamine, hexane, NH3 aq., and hexane + NH3 aq. were mixed with ACC and left for two weeks. Aragonite was formed only from the mixture of hexane and NH3 aq. Although the detailed mechanism requires further investigations, the obtained results suggest that both hydrophobic and basic properties are required for the crystallization of ACC to aragonite.

Novel tributyl phosphate-based deep eutectic solvent: Application in microwave assisted extraction of carotenoids

A contribution to the use of deep eutectic solvents (DES) and microwave-assisted extraction (MAE) was made for bioactive compounds recovery, especially those with lipophilic character, from tomato and carrot samples rich in carotenoids. For the first time, a novel deep eutectic solvent was synthesized, comprising tributyl phosphate (TBP) as a hydrogen bond acceptor and acetic acid (AcOH) as a hydrogen bond donor. The total antioxidant capacity (TAC) of tomato and carrot extracts obtained by MAE, in which optimization of operational parameters and modeling were made with the use of Box-Behnken design of the response surface methodology (RSM), was evaluated using the Cupric Reducing Antioxidant Capacity (CUPRAC) method. For the highest TAC, operational parameters that best suit the MAE procedure were set at 80 °C, 35 min, and 25 mL/2.0 g. The TAC values of extracts obtained by MAE using TBP:AcOH, 1:2 (mol/mol) were examined against those of extracts acquired by classical solvent extraction using a mixture of hexane, ethanol and acetone (H:E:A, 2:1:1 (v/v/v)) mixture. TAC of extracts in DES varied between 5.10 and 0.71 lycopene equivalents (mmol LYC kg−1). The highest extraction yield comparable to conventional organic solvents was obtained with TBP:AcOH (1:2). It was observed that, in addition to lipophilic antioxidants, some hydrophilic antioxidant compounds were partially extracted with the proposed DES. Moreover, the extracted antioxidant compounds were identified and quantified by HPLC analysis. The proposed DES and MAE process will find potential application for hydrophobic antioxidant extraction from tomatoes and carrots on an industrial scale after further studies.

تحضير ودراسة اللايكوبين الطبيعي والنانوي في تثبيط نمو الخلايا السرطانية خارج الجسم الحي In vitro

The effectiveness of both natural and nano-lycopene extracted from tomato waste powder in affecting the growth of cancer cells outside the body was studied. The study included the preparation of natural lycopene extract, using the triple mixture of hexane, acetone, and ethanol in proportions 2:1:1 and drying it, then preparing the nanocomposite using the high-energy mechanical grinding technique, and its dimensions were estimated using a Scanning Electron Microscope (SEM) and which was 78nm, and the effectiveness of the two preparations was tested in Inhibition of cancer cell lines of the human mouth and skin, during three periods of time 12, 24, 72 h and at concentrations of both natural and nano-lycopene 0.0,150, 300, 600, 1200, 2400 micrograms/ml, the results of the study showed There was a significant inhibitory effect p≤0.05. for both natural and nano-lycopene in the growth of cancer cells, and nano-lycopene was significantly superior to natural lycopene for skin and mouth models, and the inhibition effect of cancer cells increased for both natural and nano-lycopene with increasing concentration and period, and the highest percentage of inhibition for natural lycopene was 71% and 79.8% While the highest percentage of inhibition for nanoscale icon was 85.2% and 93.1% at a concentration of 2400 µg/ml for 72 h and for skin and oral cancer cell lines, respectively.

Dehydration‐Induced Cluster Consolidation in a Metal‐Organic Framework for Sieving Hexane Isomers

AbstractMetal‐organic frameworks (MOFs) that exhibit dynamic phase‐transition behavior under external stimuli could have great potential in adsorptive separations. Here we report on a zinc‐based microporous MOF (JNU‐80) and its reversible transformation between two crystalline phases: large pore (JNU‐80‐LP) and narrow pore (JNU‐80‐NP). Specifically, JNU‐80‐LP can undergo a dehydration‐induced cluster consolidation under heat treatment, resulting in JNU‐80‐NP with a reduced channel that allows exclusion of di‐branched hexane isomers while high adsorption of linear and mono‐branched hexane isomers. We further demonstrate the fabrication of MOF‐polymer composite (JNU‐80‐NP‐block) and its application in the purification of di‐branched isomers from liquid‐phase hexane mixtures (98 % di‐branched) at room temperature, affording the di‐branched hexane isomers with 99.5 % purity and close to 90 % recovery rate over ten cycles. This work illustrates an interesting dehydration‐induced cluster consolidation in MOF structure and the ensuing channel shrinkage for sieving di‐branched hexane isomers, which may have important implications for the development of MOFs with dynamic behavior and their potential applications in non‐thermal driven separation technologies.

Dehydration-Induced Cluster Consolidation in a Metal-Organic Framework for Sieving Hexane Isomers.

Metal-organic frameworks (MOFs) that exhibit dynamic phase-transition behavior under external stimuli could have great potential in adsorptive separations. Here we report on a zinc-based microporous MOF (JNU-80) and its reversible transformation between two crystalline phases: large pore (JNU-80-LP) and narrow pore (JNU-80-NP). Specifically, JNU-80-LP can undergo a dehydration-induced cluster consolidation under heat treatment, resulting in JNU-80-NP with a reduced channel that allows exclusion of di-branched hexane isomers while high adsorption of linear and mono-branched hexane isomers. We further demonstrate the fabrication of MOF-polymer composite (JNU-80-NP-block) and its application in the purification of di-branched isomers from liquid-phase hexane mixtures (98 % di-branched) at room temperature, affording the di-branched hexane isomers with 99.5 % purity and close to 90 % recovery rate over ten cycles. This work illustrates an interesting dehydration-induced cluster consolidation in MOF structure and the ensuing channel shrinkage for sieving di-branched hexane isomers, which may have important implications for the development of MOFs with dynamic behavior and their potential applications in non-thermal driven separation technologies.

Development and Validation of High-Performance Thin Layer Chromatographic Method for Simultaneous Estimation of Curcumin and Artemisinin

Curcumin and Artemisinin are proposed to be formulated as combination therapy to expand the antimalarial effect in resistant and liable isolates. The present research work was to develop and validate a simple, accurate, precise, high-performance thin layer chromatographic method for simultaneous determination of Curcumin and Artemisinin. The chromatographic separation was carried out on a precoated silica gel aluminum plate, 20 × 20 cm, 100μm thickness, with a mixture of Hexane, Toluene and Ethyl acetate (6:1:3) as mobile phase UV detection was performed at 496nm. The Rf were 0.23 and 0.76 for Curcumin and Artemisinin, respectively. Calibration plots were linear over the concentration range 200-1000ng/band for both Curcumin and Artemisinin. The method was validated in accordance with ICH Q2(R1) guidelines for linearity, sensitivity accuracy, precision, and robustness. The percent recoveries in terms of accuracy for the synthetic mixture were found to be 99.8% to 100.0% and 99.94% to 100.4%, and the pooled percent relative standard deviation for repeatability and intermediate precision studies was found to be 0.015-0.042% and 0.008-0.070% for Curcumin and Artemisinin, respectively. A factorial design was used to optimize the chromatographic conditions for the robustness study. In conclusion, a novel, simple, accurate and reproducible HPTLC method was developed and could be applied for quality control testing of Curcumin and Artemisinin in synthetic mixture.

A Microporous Multi-Cage Metal-Organic Framework for an Effective One-Step Separation of Branched Alkanes Feeds.

The improvement of the Total Isomerization Process (TIP) for the production of high-quality gasoline with the ultimate goal of reaching a Research Octane Number (RON) higher than 92 requires the use of specific sorbents to separate pentane and hexane isomers into classes of linear, mono- and di-branched isomers. Herein we report the design of a new multi-cage microporous Fe(III)-MOF (referred to as MIP-214, MIP stands for materials of the Institute of Porous Materials of Paris) with a flu-e topology, incorporating an asymmetric heterofunctional ditopic ligand, 4-pyrazolecarboxylic acid, that exhibits an appropriate microporous structure for a thermodynamic-controlled separation of hydrocarbon isomers. This MOF produced via a direct, scalable, and mild synthesis route was proven to encompass a unique separation of C5/C6 isomers by classes of low RON over high RON alkanes with a sorption hierarchy: (n-hexane≫n-pentane≈2-methylpentane>3-methylpentane)low RON≫(2,3-dimethylbutane≈i-pentane≈2,2-dimethylbutane)high RON following the adsorption enthalpy sequence. We reveal for the first time that a single sorbent can efficiently separate such a complex mixture of high RON di-branched hexane and mono-branched pentane isomers from their low RON counterparts, which is a major achievement reported so far.

Application of super base calcium oxide catalyst in the synthesis of stearamide surfactants by amidation

Surfactant is a substance that can reduce surface tension, which has two groups in one molecule: hydrophilic and hydrophobic. These two groups, in the same molecule, have different degrees of polarity. In this study, stearic acid was amidated with urea using a super base calcium oxide catalyst in a mixture of hexane and isopropanol solvents. The study was carried out by observing two process-independent variables: the reaction temperature in the range of 55˚C, 65˚C, and 75˚C, and the reaction time in the range of 2 hours, 3 hours, and 4 hours. Optimum conditions were obtained at a temperature of 75°C and a reaction time of 3 hours, where a conversion of 89.88% was obtained. Then the research samples were analyzed using FT-IR and super base calcium oxide catalyst and analyzed for morphological properties using SEM.

Chromatographic analysis of triple cough therapy; bromhexine, guaiafenesin and salbutamol and pharmaceutical impurity: in-silico toxicity profile of drug impurity

Bromhexine (BR), guaiafenesin (GUF) and salbutamol (SAL) are formulated as Ventocough syrup® (with and without sugar), labeled to contain propyl paraben and sodium benzoate as inactive ingredients. They are used to make coughing more productive and easier. A crucial element and a major issue in the pharmaceutical industry is the control of organic related impurities to obtain safe and effective treatment. Guaiacol (GUL) is reported to be GUF related impurity that was proved to be extremely toxic (toxic rating class 5), and its use should be banned. In this work, In-Silico study and ADMET estimation were conducted to predict GUL pharmacokinetic properties and its toxicity profile. Additionally, two chromatographic methods were conducted to analyze the studied components along with GUF impurity in the presence of the labeled dosage form excipients. The In-Silico study assured that GUL has oral rat acute toxicity and it is considered to be skin sensitizer. On the other hand, the developed TLC- densitometeric method depended on using a mobile phase mixture of hexane: methylene chloride: triethylamine (5.0:6.0:0.3, by volume) as a developing system. UV-Scanning was performed immediately at 275 nm for SAL, GUF and GUL, while scanning at 310 nm was used for scanning BR. Linearity was established in the ranges of 0.25–4.0, 0.25–4.0, 0.5–8.0 and 0.1–1.6 µg/band for BR, SAL, GUF and GUL, respectively. In the developed HPLC method, separation was performed on X-Bridge® C18 column (250 × 4.6 mm, 5 μm) using a solvent mixture of 0.05M disodium hydrogen phosphate pH 3 with aqueous phosphoric acid: methanol (containing 0.3%, v/v triethylamine) (40:60, v/v). Detection was done at 225 nm and separation was achieved within 10 min. Linearity was proved in the range of 2–50 µg/mL for the proposed drugs. Validation of the developed methods was done and all the calculated parameters were within the acceptable limits recommended by ICH guidelines. After that, methods were used to examine the potency of the selected marketed dosage forms and concentrations of all drugs were within the acceptable limits. Additionally, complete separation between the studied drugs and the additives were observed. The developed methods can be used during routine quality control analysis of the proposed drugs when the required issues concern on sensitivity, selectivity and analysis time.Graphical

Valorization of Monoraphidium sp. microalgal biomass for human nutrition applications

The green microalga Monoraphidium sp. has potential for biodiesel production since it grows fast and can accumulate high levels of lipids. However, there is a lack of information on the potential use in human nutrition. In this work Monoraphidium sp. was characterized in terms of macronutrients with a special focus on the fatty acid profile of the lipid fraction and on the amino acid profile of the proteins. Furthermore, aiming at nutrient valorization, various methods for lipid extraction that could be used in the production of high quality and safe foods were investigated. To this end, the focus was on cell disruption methods in order to optimize oil recovery. The Monoraphidium sp. biomass had a high protein concentration (44.5 %) and a relatively low lipid concentration (12.5 %) but was rich in ω-3 fatty acids demonstrating its high nutritive value. Regarding cell disruption, ultrasonication and high-speed homogenization were insufficient to disrupt cells under the conditions examined. On the other hand, the effectiveness of the ball milling was regulated via processing time and water-to-biomass ratio and complete cell disruption could be achieved by this method. For lipid extraction, solvent extraction using a mixture of food-grade hexane and ethanol resulted in an oil recovery of 70.4 %, whereas using ethanol alone as an environmentally friendly solvent resulted in an oil recovery equal to 54 %. Supercritical CO2 extraction resulted in a lower oil recovery (25 %), whereas ethanol addition, as a cosolvent to CO2, significantly increased the oil recovery (60 %).

Profile, health risk assessment and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in terrestrial snails and some aquatic species consumed in parts of Ogbia LGA, Bayelsa, Nigeria

Abstract The determination of Polycyclic Aromatic Hydrocarbons (PAHs) in giant land snails (Achatina achatina) and three aquatic species [mudfish (Clarias anguillaris), mud crab (Scylla serrata), and prawn (Palaemon maculatus)] in Ogbia LGA, their origin and their health implications on consumers were the focus of this work. PAHs analysis was done with Gas Chromatography couple to a Mass Spectrometer Detector (GC-MS), after extractions with 1:1 mixture of hexane and dichloromethane and clean-up with silica gel column. Total PAHs (∑16PAHs) in µg/kg in edible tissues averaged: 3342.26±845.70 for snails, 393.14±452.50 for fishes, 382.22±235.72 for crabs, and 344.81±91.93 for prawns respectively. The hazard indices showed some potential for non-carcinogenic harms: very high for snails, moderately high for fishes and crabs, and slightly high for the prawns. The calculated benzo(a)pyrene equivalent concentrations (PEC) for species were higher than the estimated screening value (SV) of 3.95 µg/kg, an indications of possible carcinogenic effects on consumers of these foods. However, the excess cancer risk (ECR) did not indicate threat of additional cancer risk as most of the calculated values (except in some snails’ samples with values < 10-4) were less than the acceptable standard of 1.0x10-6 established by the USEPA. Source diagnostic ratios revealed that source of PAHs were largely pyrolytic. The presence of these PAHs in these edible species, and possible further accumulations and its attendant impacts on human’s health calls for periodic monitoring.

Reusing a residue from the juice industry: extraction of oil from passion fruit seeds and its incorporation into liposomes

AbstractBACKGROUNDPassion fruit seeds are a residue of the pulp and juice production industry and have the potential to be used for the extraction of vegetable oil contained in them, which is rich in bioactive compounds. This work evaluated the extraction of oil using organic solvents (mixtures of hexane–ethanol–water and hexane–methanol–water) and the use of ethanol as an alternative to methanol, which is used in traditional methodologies. Several solvent mixtures were investigated to determine the condition that provides the highest oil yield. Subsequently, liposomes were produced using the ethanol injection method and the influence of oil addition on the physical–chemical characteristics of the nanoparticulated system was evaluated.RESULTS AND CONCLUSIONThe results showed that the highest oil yield was obtained using the mixture of hexane, ethanol and water, indicating the possibility of replacing methanol with a less toxic solvent. In addition, good results were obtained for the incorporation of lipids with passion fruit oil into liposomes, with the best conditions obtained being for lipid concentrations of 4.64 and 6.96 mmol L−1 with 10% and 17% of oil content, respectively. © 2023 Society of Chemical Industry (SCI).

Vapor-liquid-liquid equilibrium (VLLE), density, and viscosity of the ternary mixtures of normal hexane, water and bitumen at T=185–210°C and at P= 2.5 MPa

This paper presents a study on the vapor-liquid-liquid equilibrium (VLLE) of a ternary system consisting of normal-hexane (n-C6) as a solvent, water (H2O), and Mackay River bitumen. The study was conducted at temperatures ranging from 185 to 210 °C and a pressure of 2.5 MPa. The solvent/steam and solvent/bitumen ratios were varied to understand the effect of solvent (n-C6) on the phase behavior and the thermophysical properties of the associated phases. The co-injected solvent with steam is often reported as the concentration of solvent in the solvent/steam mixture. Two concentrations of n-C6 in n-C6/water mixture, including mole fractions of 0.01 and 0.05 (i.e., 6.85 and 27.70 vol.%), were considered to examine the effect of the co-injected solvent with steam. Also, two different mole fractions of n-C6 in the mixture of bitumen/n-C6 at 0.7 and 0.4 (37.45 and 14.61 vol.%), respectively, were considered to examine the effect of solvent solubility in bitumen. In addition to the VLLE study, the viscosity and density of the two distinct liquid phases, hydrocarbon-rich oleic and water-rich aqueous phases, were measured and reported. The results from the experiment infer that the concentration of n-C6 co-injected with steam does not significantly affect the equilibrium phase concentrations and thermophysical properties. However, the mixture showed liquid-liquid equilibria (LLE) instead of the vapor-liquid-liquid equilibria (VLLE) when the concentration of n-C6 in bitumen/solvent mixture was less than the equilibrium solubility of n-C6 in the hydrocarbon-rich phase at that operating condition. Furthermore, the results suggest that the presence of bitumen in equilibrium with n-C6 and H2O has no significant effect on the concentration of n-C6 in the vapor phase when compared with the n-C6/H2O binary mixture. Thermodynamic modelling of the VLLE data was performed using the cubic plus association equation of state (CPA EoS). The matching parameters were obtained by tuning the two-phase data, and those parameters were used in predicting the VLLE data. The model was also used to construct the phase regions of the solvent/bitumen/water system on the ternary diagram at different temperatures and pressures. Different phase regions were determined by phase stability analysis. The findings provide insight into steam/solvent condensation behavior with applications to the solvent-aided thermal recovery of bitumen from oil sands.

Investigating the hydrophilicity of phenol formaldehyde foams: Effects of synthesis parameters

AbstractOpen‐cell phenol (P) formaldehyde (F) foams are used for various applications such as hydroponic seed germination, flower arrangements, and sound insulation. This study investigated the influence of various parameters such as F/P molar ratios, blowing agents, surfactants, wetting agents, polymeric and inorganic additives, and oxidizing agents on the hydrophilicity of PF foams. Experimental results indicate that an F/P ratio of 1.8 was ideal for producing phenolic foams with good foam structure, uniform pore distribution, and favorable mechanical properties. A mixture of pentane and hexane at a mass ratio of 1:3 (wt/wt) used as a blowing agent resulted in a foam with the lowest density. With the optimal foaming catalyst (p‐toluene sulfonic acid) at a loading of 28 wt%, the foam exhibited a low density and excellent mechanical properties. A phenolic foam with a low density (39.27 kg/m3), high water absorption capacity (1210 wt%) and high open cell content (78.94%), was achieved by combining 6 wt% Tween‐80 as the surfactant and 3 wt% sodium dodecyl sulfate as the wetting agent. Additionally, 6.5 wt% loading of H2O2 led to a slight decrease in the foam density (38.46 kg/m3), but with a remarkable improvement in the wetting characteristics (water absorption capacity—2404 wt% and nearly 100% open cell content of the produced foam.

Single injection by LC-ESI-MS/MS for simultaneous determination of organophosphate tri- and di-esters in plant tissue based on ultrasonic-assisted sequential extraction and single-step purification

A novel methodology based on ultrasonic-assisted sequential extraction, dispersive-SPE purification, and single-injection on liquid chromatography-tandem mass spectrometry (LC-MS/MS) is proposed, for the first time, to simultaneously measure 14 tri-OPEs and 9 di-OPEs in plant tissues. The samples were successively ultrasonicated with a mixture of hexane:dichloromethane (1:1, v/v) and 8% acetic acid in acetonitrile for extracting tri- and di-OPEs purified with graphitized carbon black and quantitated on LC-MS/MS at the same time. The recoveries of targeted tri- and di-OPEs in the matrix spike ranged from 66% to 120% and 71% to 110% respectively. The proposed method was validated by processing eight types of common vegetables including spinach (Spinacia oleracea L.), lettuce (Lactuca sativa), carrot (Daucus carota var. sativa Hoffm.), sweet potato (Solanum tuberosum L.), cucumber (Cucumis sativus L.), tomato (Solanum lycopersicum L.), green beans (Phaseolus vulgaris), and cowpeas (Vigna unguiculata), with the recoveries of surrogates ranging from 84% to 98%.

Development and validation of an analytical methodology based on solvent extraction and gas chromatography for determining pesticides in royal jelly and propolis

We propose a new analytical methodology to determine seven pesticides (atrazine, chlorpyrifos, chlorfenvinphos, α-endosulfan, bromopropylate, coumaphos, and τ-fluvalinate) in royal jelly and propolis products using gas chromatography-mass spectrometry. Sample treatment, with minor modifications for propolis, consisted of a solvent extraction with a hexane and isopropanol mixture, and a further clean-up step. Meanwhile, chromatographic analysis (<25 min) was performed in a DB-5MS column under programmed temperature conditions. In all cases we validated the method in terms of selectivity, limits of detection (0.1–2.8 μg kg−1) and quantification (0.3–9.2 μg kg−1), linearity, matrix effect (<±20 %), trueness (recoveries between 93 % and 118 %), and precision (relative standard deviation < 11 %). All royal jelly liquid dietary supplements were positive for chlorfenvinphos and, in the case of one of them, for α-endosulfan; chlorfenvinphos was determined in some fresh royal jelly samples, and no pesticide residues were detected in the propolis samples analysed.

Acaricides Application Rates and Residue Levels in Homemade Sprays, Soil and Water from the Southern Ewaso Nyiro River in Kajiado West Sub County, Kajiado County, Kenya

Acaricides used in controlling ectoparasites (ticks) is the most preferred and economical sound conventional mode of tick eradication. The study aimed at determining acaricide application rates and residue levels in the homemade cattle sprays, soils within the spraying sites and water from the nearby southern Ewaso Nyiro River. The livestock drink river water which is used for domestic purposes. Acaricide residues levels analyzed were those used by farmers in for homemade cattle sprays. The cattle sprays and soil samples were collected from ten selected homes spraying sites randomly from 138 willing farmers in the May and November representing wet and dry seasons respectively in 2018. The sprays were collected after farmers prepared them in the usual way before spraying their animals. The livestock farmers’ ways of mixing and application of acaricides after normal preparation was assessed. The different acaricides identified were analysed for active ingredient levels after preparation using Gas chromatography-Mass spectrometry. Water samples were collected from six sites adjacent to the homes where the sprays were prepared since some homes were found to share the same water drawing area. Solvents used were triple distilled for samples extractions. The homemade sprays and water samples were extracted using dichloromethane while Soxhlet method for soil in a mixture of acetone and hexane in the ratio of 1:3. Samples were concentrated using a rotary evaporator and the clean-up through aluminium oxide chromatographic glass column. Refrigerator was used for sample storage while a Hewlett-Packard Agilent Gas chromatography system equipped with a mass selective detector was used for quantification of acaricide residues levels. Out of the nine acaricides reported by farmers through the questionnaire, three namely amitraz, cypermethrin and deltamethrin were detected in the homemade cattle sprays and soil samples. Amitraz levels ranged from 884±25.3 to 12,236±14.54 µg/L, Cypermethrin was at 3,834±80.2 to 11,972±74.0 µg/L with Deltamethrin at 3,879±33.2 to 12,298 ±82.1 µg/L in the dry while amitraz was at 5,430±96.10 to 11,634±107.2 µg/, 8,975± 103.7 to 10,383±562 µg/L for Cypermethrin while Deltamethrin was only used by home 3 at concentration of 4,781± 125.8 µg/L in the wet seasons in homemade cattle sprays. In the soil, acaricides were in the range of 3,129±98.7 to 10,641±144.2 µg/kg for amitraz, 3,041±33.15 to 8,654±141.2 µg/kg, Cypermethrin and 1,341±58.06 to 8,167±16.4 µg/kg Deltamethrin in dry and 3,875±97.3 to 7,905±184.2 µg/kg amitraz, 4,832±86.7 to 8,694±146.9 µg/kg Cypermethrin. Deltamethrin was only used by home 3 at a level of 2,367±76.9 µg/kg in the wet season. The analysis revealed that homemade cattle sprays in the sub-county had low levels of amitraz, cypermethrin and deltamethrin than those recommended by the manufacturers of 50,000-400,000 µg/L, indicating that the acaricides were over diluted leading to the observed tick re-occurrence in Kajiado West Sub County.