Determination Of Chemical Composition Research Articles

Microstructural Insights and Composition Analysis of a Fractured Brass Alloy of Unknown Composition Using Advanced Characterization Techniques

This study aims to investigate the microstructural and compositional characteristics of a fractured brass alloy using energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The brass alloy, initially of unknown composition, was determined to consist of 63.65 at% Cu, and 36.35 at% Zn through EDS analysis. Microstructural analysis via SEM revealed a typical ductile fracture pattern with necking and dimple formation, indicative of significant plastic deformation prior to failure. The alloy exhibited a grain size ranging from 10 µm to 80 µm and displayed both α-phase (FCC structure) and possible traces of β-phase, though XRD detected only the α-phase due to the low concentration of β-phase (<5%). A comparison between EDS and XRD results for analyzing chemical composition showed that good assumptions could be made from the lattice parameters of the binary alloy following Nelson-Relay function to predict an approximate composition in binary alloy systems, which was found to be 34 at% Zn in our analysis. Furthermore, the sample’s crystal structure was confirmed as FCC, which supported its observed ductility and plastic deformation prior to fracture. The SEM analysis also confirmed that the material went through an annealing process. The fracture morphology further showed that the FCC structure and the annealing process both contributed to the material’s increased ductility. The analysis further confirms that EDS is more reliable for chemical composition determination in an alloy system. Evidence of annealing twinning in the SEM images suggests the sample underwent an annealing process, contributing to its enhanced ductility.

Chemical composition determination and transcriptomic analyses provide insight into the differences between wild and grafted Semen Ziziphi Spinosae

Semen Ziziphi Spinosae (SZS) is a traditional Chinese herbal medicine widely used to treat insomnia and anxiety in clinical practice. Currently, the demand for SZS is increasing every year, but the production of wild SZS is unstable due to environmental factors. Grafting sour jujube scions onto sour jujube or jujube tree stocks can achieve a high production rate within a short period of time. However, the effects of grafting on the quality of SZS have not been reported. This study investigated the differences between wild-type and grafted SZS from three aspects: phenotype, chemical composition, and molecular mechanism. The findings revealed that the grafted specimens were generally larger in morphology and lighter in color than the wild-type samples. The dimensions of both the grafted specimens were generally larger than those of the wild specimens. The HPLC-ELSD results revealed that the three main chemical components in the grafted SZS, namely, spinosin, jujuboside A, and jujuboside B, had higher contents than their wild-type counterparts. Comprehensive transcriptome sequencing analysis and KEGG annotation revealed that DEG enrichment between grafted and wild-type SZS occurred mainly during stress resistance and rootstock scion healing. There were 23 DEGs that may encode enzymes involved in the biosynthetic pathway of flavonoids and 21 genes encoding terpenoid saponins. Further investigation revealed that the expression of the genes C4H, CHS, CHI, and F3’5’H in the flavonoid biosynthesis pat.hway and HMGR, MVK, MVD, and FPPS in the saponin biosynthesis pathway accounted for the difference in quality between grafted and wild SZS. Furthermore, WGCNA identified 15 core genes related to medicinal ingredients between grafted and wild SZS. These results provide support for further research on the differences in the quality of medicinal ingredients between grafted and wild SZS.

Exploring the biosorption of nickel and lead by Fusarium sp. biomass: kinetic, isotherm, and thermodynamic assessment.

Fungal biomass is as a cost-effective and sustainable biosorbent utilized in both active and inactive forms. This study investigated the efficacy of inactivated and dried biomass of Fusarium sp. in adsorbing Ni2+ and Pb2+ from aqueous solutions. The strain underwent sequential cultivation and was recovered by filtration. Then, the biomass was dried in an oven at 80 ± 2°C and sieved using a 0.1-cm mesh. The biosorbent was thoroughly characterized, including BET surface area analysis, morphology examination (SEM), chemical composition (XRF and FT-IR), thermal behavior (TGA), and surface charge determination (pH-PZC and zeta potential). The biosorption mechanism was elucidated by fitting equilibrium models of kinetics, isotherm, and thermodynamic to the data. The biosorbent exhibited a neutral charge, a rough surface, a relatively modest surface area, appropriate functional groups for adsorption, and thermal stability above 200°C. Optimal biosorption was achieved at 25 ± 2°C, using 0.05g of adsorbent per 50mL of metallic ion solution at initial concentrations ranging from 0.5 to 2.0mg L-1 and at pH 4.5 for Pb2+ and Ni2+. Biosorption equilibrium was achieved after 240min for Ni2+ and 1440min for Pb2+. The process was spontaneous, mainly through chemisorption, in monolayer for Ni2+ and multilayer for Pb2+, with efficiencies of over 85% for both metallic ion removal. These findings underscore the potential of inactive and dry Fusarium sp. biomass (IDFB) as a promising material for the biosorption of Ni2+ and Pb2+.

Method of obtaining and possibility of using of new complex fertilizers from flotation sludge – potassium-magnesium ore processing wastes

The results of research on properties of cinders obtained by high-temperature roasting of clay-salt waste (sludge) after processing K-Mg ores are presented. Cinders are used as complex fertilizers, ameliorant components and microelement fertilizers. Secondary wastes, after extraction of Pd, Pt, Ag from burnt sludge (cinder), consist of sludge after deslagging of crushed cinder and “tails” after sand enrichment. Mixing these products, moistening, granulating and sintering forms result in a sintering product (CP) that is ready for application as complex fertilizer, ameliorating additive and microfertilizer. A study of the chemical composition and composition of impurities of cinders and CP was carried out. The identity of the composition of cinders and CP has been established. Tests with cinders and CP as a complex of fertilizers, ameliorants and microfertilizers were carried out. The research was carried out on the experimental field of Perm Agricultural Research Institute, on sod-podzolic heavy loamy soil formed on the deluvium of Permian clays, this soil represents up to 70% of the arable lands of the Perm region, the studied crop was potato. The yield of potato when applying cinder as an ameliorant additive was higher by 6.05 t/ha compared to the control (the use of traditional fertilizers provided an increase of 3.56 t/ha). For the first time determination of chemical composition including trace elements studies was fulfilled in potato tubers from unfertilized variants, plots fertilized with traditional fertilizers and plots fertilized with cinders. Two components of tubers – peel and pulp – were analyzed using a mass spectral method, with decomposition in a closed system (autoclave). Most of the elements were characterized by a higher content in the peel (almost an order of magnitude) compared to the pulp. An inverse relationship was observed for P and S, their content was higher in pulp than in peel. In the variant with the use of cinder, a higher content of microelements, especially rare-earths elements, was observed compared to the control. A method for processing sludge to extract Pd, Pt, Ag, results in secondary wastes, that can be used as complex slow-release fertilizers, ameliorating additives and microelement-containing fertilizers.

Effect of alkali treatment and fungal degradation on the nanostructure and cellulose arrangement in Scots pine cell walls – A neutron and X-ray scattering study

Research on new conservation treatments for historical wood requires considerable amounts of appropriate wood material, which is hard to acquire. Thus, we produced biologically and chemically degraded model wood that could be used as a representative material in future research on consolidating agents. Using chemical composition determinations, we found that fungal decay targeted mainly polysaccharides, while alkaline treatment mostly reduced hemicelluloses and lignin content. X-ray and neutron scattering showed that all decayed samples had increased disorder in microfibril alignment and larger elementary fibril cross-sections, and alkaline-treated samples had much larger elementary fibril spacing compared to those decayed by fungi. These nanoscale and chemical differences correlate with physical property changes. For example, decreased cellulose crystallinity and increased disorder of the microfibrils in degraded cell walls likely contribute to the lower elastic moduli measured for these cell walls. The obtained data improves understanding of how degradation alters wood structures and properties across length scales and will be valuable for future studies focusing on archeological wood. Moreover, it leads to the conclusion that it is more appropriate to develop treatments that consider not only spatial variability and degree of wood degradation but also the corresponding molecular and nanoscale changes in the cell walls.

Boriding of Low-Carbon Steel by Plasma Method: Microstructure and Coating Properties

In materials science, steel boration is a promising type of thermochemical diffusion process, the purpose of which is the introduction of hard and wear-resistant boride particles into the surface layers of the metal. The main disadvantage of boration is the fragility of borated layers, especially boride. Currently, there are promising methods for the formation of a composite structure, which are based on the treatment of surface layers of steels with concentrated energy flows (laser, electron beam and plasma). The work includes studies of microstructure, hardness measurements, analysis of phase composition, and determination of chemical composition in local locations, wear tests under various conditions, and adhesion testing of the coatings obtained after plasma boration. As the degree of alloying of the molten layer decreases in the direction from the surface to the base metal, zones of overeutectic, eutectic and pre-eutectic types with a different combination of structural components are formed. The material obtained after borating a mixture of 40% B + 10% Fe is characterized by the highest level of microhardness, which is 1000...1300 HV. The highest results in friction tests are provided by boration of a powder mixture of 40% B + 10% Fe.

Performance and environmental impact of ethanol-kerosene blends as sustainable aviation fuels in micro turbo-engines

The research experimentally examines the viability of ethanol (E) as a sustainable aviation fuel (SAF) when mixed with kerosene (Ke) – Jet A aviation fuel + 5% Aeroshell oil. Various blends of ethanol and kerosene (10%, 20%, and 30% vol. of ethanol added in kerosene) were subjected to testing in an aviation micro turbo-engine under different operational states: idle, cruise, and maximum power. During the tests, monitoring of engine parameters such as burning temperature, fuel consumption, and thrust force was conducted. The study also encompassed the calculation of crucial performance indicators like burning efficiency, thermal efficiency, and specific consumption for all fuel blends under maximum power conditions. Physical-chemical properties of the blends, encompassing density, viscosity, flash point, and calorific power, were determined. Furthermore, elemental analysis and FTIR were used for chemical composition determination. The research delved into analyzing the air requirements for stoichiometric combustion and computed resulting emissions of CO2 and H2O. Experimental assessments were performed on the Jet Cat P80® micro-turbo engine, covering aspects such as starting procedures, acceleration, deceleration, and emissions of pollutants (CO and SO2) during diverse engine operational phases. The outcomes reveal that the examined fuel blends exhibited stable engine performance across all tested conditions. This indicates that these blends hold promise as sustainable aviation fuels for micro turbo-engines, presenting benefits in terms of diminished pollution and a more ecologically sound raw material base for fuel production.

Quantitative analysis of UF4 and ThF4 in Indian MSR fuel using laser induced breakdown spectroscopy

The Molten Salt Reactor (MSR) represents a significant addition to India's clean energy initiative through nuclear energy. Noteworthy for its inherent safety features and the utilization of mixed fluoride salts (U, Th, Li) as molten-liquid fuel, this reactor stands out as a unique advancement. This paper showcases the application of Laser-Induced Breakdown Spectroscopy (LIBS) to ensure the chemical composition of the fuel. The micro-destructive nature of the analysis, minimal sample preparation requirements and the potential for remote analysis position LIBS as a viable alternative to Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The study encompasses the quantification of UF4 and ThF4, demonstrating both univariate and multivariate chemometrics calibration approaches. Various normalization methods on the raw spectral data are explored, and the results are meticulously compared. Upon evaluating different analytical methods, the optimal accuracy and precision achieved were in the range of approximately 2.6% and 3.9% for UF4, and about 0.4% and 0.5% for ThF4, respectively. This underscores the effectiveness of LIBS in ensuring the accurate determination of chemical composition in the context of MSR fuel.

Angle-resolved X-ray photoelectron spectroscopy intensity modeling of SiNx ultrathin layer grown on Si (100) and Si (111) substrates by N2 plasma treatment

In this work, we investigate the silicon nitridation process using a N2 plasma Glow Discharge Source (GDS) in an ultra-high vacuum chamber. In situ Angle Resolved X-ray Photoelectron Spectroscopy (ARXPS) measurements were performed to determine various chemical environments of the surface species. The main goals of this study are determination of the film chemical composition, to estimate its thickness and identify various phenomena taking place during the nitridation process under different experimental conditions. To achieve these objectives, we developed an ARXPS intensity model for an ultrathin SiNx overlayer. Based on the ARXPS results, which indicate that the silicon nitride film is not homogenous, we adopted a bi-layer model composed of two SixNyOz layers with varying thickness and chemical composition. The model is built from analysis of photoelectron intensities, considering a comparison between experimental and theoretical data. This bi-layer model revealed that the silicon nitride layer consists of a surface layer composed of approximately equal amounts of silicon and nitrogen (50% each), and an interfacial layer containing varying amounts of oxygen depending on experimental parameters. The presence of oxygen is due to residual air contamination in the vacuum chamber and/or to Si native oxide. The estimated thickness of silicon nitride film is less than 9 nm, depending on the nitridation time and temperature.The model developed in this work enabled us to study the effects of initial surface state (as received or chemically cleaned), Si substrate crystallographic orientation (such as (100) and (111)), and the nitridation temperature (room temperature and 500°C). The diffusing species (N+, N2+, O+), which play a crucial role during nitridation, were found to be influenced by temperature, treatment time, and substrate orientation. The diffusion phenomenon competed with other processes such as NO desorption, leading to a significant impact on formation of the SiNx film. Furthermore, we compared the thickness obtained from the ARXPS model using cross-sectional High-Resolution Transmission Electron Microscopy (HR-TEM) images. Additional Low-Energy Electron Diffraction (LEED) measurements indicated that the SiNx film was amorphous.

Antimicrobial properties of Clausena anisata (Rutaceae) essential oil from Bafou area against the pathogenic fungus Candida albicans and antioxidant activity

The aim of the present work was to determine the antimicrobial and antioxidant activities of Clausena anisata essential oil. The extraction of essential oils was performed by the hydro distillation method with a Clevenger apparatus. The determination of essential oils chemical composition was conducted by gas chromatography and gas chromatography coupled with mass spectrometry. Then the antimicrobial activity was assessed using disk diffusion method and micro titration. In order to determine the antioxidant activity 2 methods were carried out: the free radical scavenging assay was performed using the DPPH+ radical (2,2-diphenyl-1-picrylhydrazyl) and the method with ABTS radical reagents (acid2, 2'-azynobis-[3-ethylbenzothiazoline-6 ​​sulfonic acid]). The yield of extraction of the essential oil was 0.77%. The study of its chemical composition revealed E- anethol (70.77%), methyl iso eugenol (13.85) as major compounds. The anti-radical DPPH test revealed a SC50 of 1g/L; 0.265g/L respectively for DPPH and ABTS tests. The results also highlighted a potent antimicrobial property. An antimicrobial screening study revealed a susceptibility of Candida albicans isolates at a concentration of 8000 ppm. This activity was characterized by minimum inhibitory concentrations of 2000 ppm for all the tested pathogenic yeasts Sab1, Sab2, Sab3, Sab250, Sab2501, Sab256, Sab259 and Sab290. The essential oil minimum inhibitory concentration (MIC) was lower than the MIC of fluconazole. The same observations were resulted with the fungicidal effect. These data can be used as a starting point for subsequent studies to produce antifungal and antioxidant drugs to face the challenge of the antimicrobial resistance and oxidative stress.

AI-Driven Optimization of PCL/PEG Electrospun Scaffolds for Enhanced In Vivo Wound Healing.

Here, an artificial intelligence (AI)-based approach was employed to optimize the production of electrospun scaffolds for in vivo wound healing applications. By combining polycaprolactone (PCL) and poly(ethylene glycol) (PEG) in various concentration ratios, dissolved in chloroform (CHCl3) and dimethylformamide (DMF), 125 different polymer combinations were created. From these polymer combinations, electrospun nanofiber meshes were produced and characterized structurally and mechanically via microscopic techniques, including chemical composition and fiber diameter determination. Subsequently, these data were used to train a neural network, creating an AI model to predict the optimal scaffold production solution. Guided by the predictions and experimental outcomes of the AI model, the most promising scaffold for further in vitro analyses was identified. Moreover, we enriched this selected polymer combination by incorporating antibiotics, aiming to develop electrospun nanofiber scaffolds tailored for in vivo wound healing applications. Our study underscores three noteworthy conclusions: (i) the application of AI is pivotal in the fields of material and biomedical sciences, (ii) our methodology provides an effective blueprint for the initial screening of biomedical materials, and (iii) electrospun PCL/PEG antibiotic-bearing scaffolds exhibit outstanding results in promoting neoangiogenesis and facilitating in vivo wound treatment.

Carcass characteristics, physicochemical traits, texture and microstructure of young and spent quails meat

The purpose of the study was to compare young (6-wk-old) and spent (52-wk-old) Japanese quail in terms of body weight, carcass characteristics, and some meat quality traits. Whole carcasses were dissected, pectoral muscles and leg muscles were sampled for determination of basic chemical composition and L*a*b* color parameters, while m. pectoralis major was sampled for texture and microstructure traits. Age of quails had a significant effect on body weight, carcass weight, carcass yield, pectoral muscle, abdominal fat and skin with subcutaneous fat, and carcass remainders contents in eviscerated carcass. Spent quails had significantly higher intramuscular fat content in pectoral and leg muscles and protein content in breast muscle, and also lower content of water in breast and leg muscles than young quails. Slaughter age significantly affected lightness (L*) and redness (a*) of pectoral muscles, as well as texture traits (except for cohesiveness) and microstructure of m. pectoralis major, except for thickness of perimysium and endomysium. Regardless of age, quail sex had an effect on the carcass traits studied (except for leg muscle content), intramuscular fat content of pectoral and leg muscles, water content of leg muscles and yellowness of pectoral muscle. In addition, a significant effect of quail sex was found on cutting work, springiness, chewiness and marked microstructural characteristics, except for vertical fiber diameter. The interaction between age and sex was significant for most slaughter and microstructural characteristics and also WB-shear force of m. pectoralis major, and L*, b* pectoral muscles. Higher fatness of carcasses, higher intramuscular fat in meat, and poorer textural and microstructural characteristics of m. pectoralis major spent Japanese quail indicate poorer fulfillment of most consumers' requirements compared to carcasses and meat of young quails.

Determination of chemical composition and antioxidant, cytotoxic, antimicrobial, and enzyme inhibition activities of Rumex acetosella L. plant extract

Determination of chemical composition and antioxidant, cytotoxic, antimicrobial, and enzyme inhibition activities of Rumex acetosella L. plant extract

Determination of chemical compositions of rosemary and sweet marjoram essential oils and their blends and their antifungal potential against potato rubbery rot disease agent Geotrichum candidum

AbstractIn this study, the chemical compositions of rosemary (Rosmarinus officinalis Spenn.) and sweet marjoram (Origanum majorana L.) essential oils, both individually and in various blend ratios, were investigated by using Gas Chromatography-Mass Spectrometry. Their antifungal activities were also determined against the potato rubbery rot disease agent, Geotrichum candidum, under in vitro and in vivo conditions. Camphor (20.69%) and terpinen-4-ol (35.13%) were determined as primary constituents in rosemary and sweet marjoram essential oils, respectively. Sweet marjoram and rosemary essential oils completely inhibited mycelial growth of G. candidum at 55.0 and 65.0 µL/Petri concentrations, respectively. Essential oils at these concentrations were found as fungicidal. Notably, a synergistic fungicidal antifungal effects were also observed in essential oil blends. Blend of sweet marjoram and rosemary essential oil in a 3:1 ratio (O75R25) significantly enhanced antifungal activity at the relatively lower concentration (45.0 µL/Petri). Microscopic observations revealed structural deformations in exposed hyphae, including cytoplasmic coagulation and vacuolization. Essential oil blend (O75R25), sweet marjoram and rosemary essential oils completely inhibited the disease lesion caused by G. candidum on potato tubers at concentrations of 100.0, 125.0, and 150.0 µL/L air, respectively. These findings emphasized that essential oil blends of rosemary and sweet marjoram have synergistic antifungal potential and can be used as effective biofungicides against plant fungal diseases.

Structural, Electrical and Corrosion Properties of Bulk Ti-Cu Alloys Produced by Mechanical Alloying and Powder Metallurgy.

Binary Ti100-x-Cux (x = 1.6 and 3.0 wt.%) alloys were produced by the application of mechanical alloying and powder metallurgy processes. The influence of the copper concentration in titanium on the microstructure and properties of bulk alloys was investigated. The synthesized materials were characterized by an X-ray diffraction technique, scanning electron microscopy, and chemical composition determination. The electrochemical and corrosion properties were also investigated. Cold compaction and sintering reduced the content of α-Ti content in Ti98.4-Cu1.6 and Ti97-Cu3 alloys to 92.4% and 83.7%, respectively. Open Circuit Potential measurements showed a positive shift after the addition of copper, suggesting a potential deterioration in the corrosion resistance of the Ti-Cu alloys compared to pure Ti. Electrochemical Impedance Spectroscopy analysis revealed significant improvement in electrical conductivity after the addition of copper. Corrosion testing results demonstrated compromised corrosion resistance of Ti-Cu alloys compared to pure Ti. In summary, the comprehensive investigation of Ti100-x-Cux alloys provides valuable insights for potential applications in biosensing.

Determination of essential oil and chemical composition of St. John’s Wort

Abstract Considering it contains a variety of physiologically active compounds, including flavonoids, common phenols, and essential oils (EOs), St. John’s wort (Hypericum perforatum L.) is a common plant in Bulgaria that is predominantly used in folk medicine to cure various disorders. Determining the chemical makeup of St. John’s wort inflorescences that were gathered from northern Bulgaria was the purpose of this investigation. The antioxidant activity of H. perforatum L. extracts was assessed using 1,1-diphenyl-2-picrilhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and Trolox equivalent antioxidant capacity (TEAC) tests on methanol extract. The amount of EO obtained by water distillation was 0.08%, with its main components (over 3%) being n-nonane (27.46%), β-sesquiphellandrene (11.17%), heptanal dimethyl acetal (5.94%), ethyl hexyl ketone (5.93%), undecane (3.75%), sabinene (3.3%), and tridecyl alcohol (3.1%). Methanol extracts were obtained from the inflorescences, with the total flavonoid content determined as 8.66 mg quercetin equivalents (QE)/mg and total phenolic content as 271.33 mg Gallic acid equivalent/g. The FRAP assay yielded 493.07 µmol/L of antioxidant activity, while the TEAC assay yielded 106.39 µmol/L, respectively. Our findings enable a comprehensive characterization of H. perforatum from Bulgaria and an assessment of its oil suitability for potential industrial applications. Additionally, the results could guide the selection of specimens for future targeted breeding efforts.

A Selection of 23 Bright Hypervelocity Gaia DR3 Stars

From the Gaia DR3 data twenty three bright hypervelocity stars that have Tycho catalogue numbers are presented. All these stars are of high galactic latitude and some may be galactic halo stars. All of them have accurate Gaia DR3 parallaxes and radial velocities. There is hardly any relevant literature on some of these stars. The Gaia DR3 astrophysical parameters of some of these stars indicate that they are of late spectral types and some are metal-poor. The astrophysical parameters are available for some of these stars in the literature but they differ from the Gaia DR3 results. Detailed chemical composition determination of these stars from an analysis of high resolution spectra is very much needed to further understand the evolutionary status and how these stars acquired such high radial velocities.

Rapid determination of chemical compositions of raw materials and intermediate products of lube base oil by near infrared spectroscopy combined with library spectral fitting method

Rapid analysis of the detailed hydrocarbon composition of vacuum gas oil, hydrocracking bottom oil, and hydrogenated lube base oil is a critical technology in the production of hydrogenated lube base oil. In this study, based on a quantity of representative samples, a novel approach for estimating the hydrocarbon composition for vacuum gas oil, hydrocracking bottom oil and hydrogenated lube base oil was developed by near infrared (NIR) spectra combined with new chemometric method called library spectra fitting. The proposed method can reduce the maintenance requirements of traditional multivariate calibration such as partial least squares (PLS) apparently. The results of NIR analysis are basically consistent with ASTM standard method, which can fulfill the needs of rapid analysis in industrial field. Currently, the technology and corresponding software tools have been applied in a petroleum refinery.

Determination of chemical composition, antioxidant activity, mass spectrometry and cytotoxicity of the Aiphanes aculeata palm fruit

Berry-type fruits from Arecaceae palms have excellent nutritional, functional and economic characteristics. This study aimed to evaluate the pulp of the Aiphanes aculeata palm fruit through the analysis of proximate composition, physicochemical parameters, micronutrients, total phenolics, antioxidant activity and cytotoxicity. In relation to macronutrients, low levels of lipids, proteins and fibers, and high levels of carbohydrates and sugars were determined. Among the micronutrients analyzed (Ca, Mg, Zn, Fe, P and K), potassium (933.04 mg/100 g) was the most abundant element in the fruit. Regarding the analysis of vitamin C, the value determined was 46.97 mg/100 g. The DPPH, FRAP and ABTS assays were used to evaluate the antioxidant activity. The extracts showed antioxidant activity in the methods used, providing potential for their application in the composition of the food products formulations with functional properties since there was no cytotoxic potential in normal cells (L-929).

Determination of chemical composition and insecticidal potential of leaf essential oil of Mentha piperita L.

Pulverised fresh Mentha piperita leaves was subjected to hydrodistillation for three hours in a Clevenger-type apparatus. The oil obtained was characterised using Gas Chromatography-Mass Spectrometry (GC-MS) and also evaluated for insecticidal activity on Callosobruchus maculatus (bean weevils) and Sitophilus zeamais (maize weevils). The oil afforded a yield of 0.78% (w/w). A total of 39 compounds were identified from their mass spectra representing 98.9% of the oil. The classes of compounds identified revealed predominance of oxygenated monoterpenoids (72.4%), hydrogenated monoterpenoids accounted for 6.0%, hydrogenated sesquiterpenoids and oxygenated sesquiterpenoids constituted 12.2 and 4.0% respectively. Other non-terpenic compounds detected in the oil accounted for 4.3% of the total oil. The most abundant compound was menthol (40.4%), other major compounds identified were menthone (12.3%), menthofuran (9.2%), 1, 8-cineole (5.6%) and limonene (5.5%). The percentage mortality of between 68-94.5% and 65-90.2% were recorded for bean weevils and maize weevils respectively after exposure to 10µl essential oil vapour in fumigation chambers for 6, 12, 18 and 24 hours. The insecticidal activity of the oil compared favourably with that of standard insecticide and so can be used to formulate an alternative insecticide from botanical source.