Microwave Plasma Atomic Emission Spectroscopy Research Articles

Determination Of Exchangeability Cations (Ec), Texture And C-Organic Content In Mineral Soils and Peat

EC or can be called exchangeable cation is a nutrient cation found in the soil. This is useful for indicating the degree of alkaline saturation, which indicates that the more saturated the soil base, the more fertile the soil will be. This study aims to obtain supporting information to obtain soil conditions that show the quality of the land as a growing medium. The method used for texture analysis on this soil refers to SNI 3423.03:1994 and C-Organic content analysis refers to SNI 4720.13:1998. The cation level test was carried out using NH4OAc solution with a Microwave Plasma Atomic Emission Spectroscopy (MP-AES) instrument. This instrument has a principle, namely atomic emission which is a form of energy produced by an atom when it returns to the ground state (Ground State) of the excited state (Excitation State). The results of this cation level test with analyte concentrations of K, Ca, Na and Mg with sample code SJ2022-01826 successively 0.65; 3,59; 0.82 and 0.94. The amount of cation content in fertile soil is worth at least 6 mg / L in accordance with the provisions of the Chemical Technical Manual.

Major and heavy metals contents and health risk assessment of pumpkin peel, flesh and seed by microwave plasma-atomic emission spectroscopy

ABSTRACT. The aim of this study was to determine the levels of major (Na, Mg, K, Ca) and heavy (Cr, Mn, Fe, Ni, Cu, Zn, Cd) metals and health risk assessment of the peel, flesh and seed of pumpkins cultivated in Ethiopia, using microwave plasma-atomic emission spectrometry. Dried powdered samples (0.5 g) were wet digested with 69% HNO3 and 30% H2O2 in microwave digester. The percent recovery for the three parts of pumpkin samples were 90-110%. The mean concentration of metals in pumpkin peel, flesh, seed samples, respectively, were K (27806±9767, 29531±2452, 10667±1133), Ca (5267±2092, 3190±900, 2919±397), Mg (4716±469, 848±349, 4668±413), Fe (158±29, 111±46, 225±56), Na (167±116, 63.1±15, 171±123), Mn (28.9±1.4, 9.61±3.2, 33.4±4.9), Zn (24.2±4.4, 10.6±4.0, 67.5±12.3), Cu (8.14±1.1, 15.1±9.3, 10.8±0.9), Ni (3.79±2.4, 2.14±1.3, 3.44±2.8), Cr (0.28±0.1, 0.36±0.2, 0.69±0.1), Cd (0.24±0.1, 0.46±0.1, 1.39±0.2) mg/kg. The hazard index (HI) of pumpkin flesh and seed indicated ingestion of pumpkin is safe from non-carcinogenic risk. The total cancer risk (CR) due to consumption of pumpkin flesh and seed through Cr and Cd from the three sampling sites are in the range 1.1 x 10-4 -1.8 x 10-4, indicating a non-risk of exposure to cancer due to the consumption of pumpkin grown in the sampling areas.
 
 KEY WORDS: Pumpkin, Mineral content, Health risk, Microwave plasma-atomic emission spectrometry
 
 Bull. Chem. Soc. Ethiop. 2023, 37(3), 533-551. 
 DOI: https://dx.doi.org/10.4314/bcse.v37i3.1

Glutathione-S-transferase (GSTM1 and GSTT1) polymorphism and lead toxicity in individuals environmentally exposed to lead

Genetic variation in enzymes involved in metal detoxification could have influence on susceptibility to lead-induced oxidative stress. The present study aimed at evaluating the effects of genetic variation of Glutathione-S- transferase gene on oxidative stress markers (GSH, SOD, CAT and MDA) among individuals environmentally exposed to lead. GSTM1 and GSTT1 null homozygous genotypes were determined by polymerase chain reaction. Blood lead levels were determined using Microwave Plasma Atomic Emission Spectroscopy (MP- AES-Agilent 4210 USA). Activities of superoxide dismutase, catalase and glutathione levels were assayed using Cayman’s commercial kits. The study found mean blood lead levels of the study subjects of 78.16± 5.79µg/dl with range from 26.6 to 191.0 µg/dl. The frequencies of GSTM1 and GSTT1 null genotypes were 23% and 50.8% respectively. The frequency was high in individuals with blood lead levels greater than 70µg/dl. Significant decreased activity of antioxidant enzymes (SOD and CAT), glutathione levels and concomitant increased of MDA concentrations were observed in individuals with GSTM1 and GSTT1 null genotypes. Therefore, findings from this study were enough to infer a causal relationship between environmental exposure to lead and oxidative stress. Individuals who are homologous null at GSTM1 and GSTT1 loci predispose to increased risk of multi-organs toxicity from environmental exposure to lead.

Comparative study of some macro & micro elements in milk samples from Abuja, Nigeria using microwave plasma atomic emission spectroscopy (MP-AES) and flame atomic absorption spectroscopy (F-AAS) methods

A comparative study was carried out for the determination of calcium, magnesium, iron and zinc contents in two brands of powdered milk samples, using the Microwave Plasma Atomic Emission Spectroscopy (MP-AES) and Flame Atomic Absorption spectroscopy (F-AAS) methods. The powdered milk samples were collected and placed in a muffle furnace at 550°C for 6 hours, and the ash contents obtained was used for the sample preparation. The percentage recoveries for the spikes were as follows: for MP-AES determination; the recoveries for the milk samples were within the range (116.9 – 163.1%) for calcium; (51.8 – 78.8%) for magnesium; (110.9 – 125.4%) for iron; (90.7 – 92.9%) for zinc. For FAAS determination; the recoveries for the milk samples were within the range (51.1 – 83.6%) for calcium; (52.2 – 61.9%) for magnesium; (77.7 – 84.8%) for iron; (46.5 – 71.7%) for zinc. The percentage recoveries showed a better recovery with MP-AES than the F-AAS method. The analysis of variance conducted using One way ANOVA method shows that there is no significant difference between the two methods used for the analysis, as the P-values (calculated probability) obtained were higher than 0.05. The values obtained for Ca, Mg, Fe and Zn content shows that only Ca was found to be within WHO/FAO standard, while Mg, Fe and Zn were found to be below the WHO/FAO standard. It is highly recommended that a 100g of any of the powdered milk used for the research work be consumed per day in order to meet up with the RDA per day, or other sources of these elements to be considered.Â

Preparation and structure analyses of Sn-bentonite for pertechnetate removal

Tin (Sn) -bentonite was prepared by ion exchange method from Ca-bentonite. For the ion exchange process, tin-chloride (SnCl2) solution was prepared from metallic tin, and the tin concentration was determined by Microwave Plasma Atomic Emission Spectroscopy (MP-AES). Sn-bentonite was characterized by X-ray fluorescence spectrometry (XRF), X-ray powder diffraction (XRPD), X-ray photoelectron spectroscopy (XPS) and 119Sn as well as iron-57 (57Fe) Mössbauer spectroscopy. 119Sn Mössbauer spectroscopy and XPS undoubtedly revealed both Sn+2 and Sn+4 ions in Sn-bentonite. SnII was attributed to be incorporated into the interlayer space while SnIV located partly in the octahedral position and in the interlayer space of montmorillonite. The removal of radioactive pertechnetate anion (99mTcO4-) was studied on Sn-bentonite in aqueous and artificial urine media. Based on the measurement results, 99mTcO4- ion can be removed, in case of aqueous media, the equilibrium is reached after 5 mins (x = 99.9 ± 0.01%, k = 4.2 ± 0.83 1/min) (Buzetzky et al., 2019), while in the case of urine media the equilibrium is reached after 30 mins (x = 59.1% ± 2.7, k = 0.18 ± 0.05 1/min). Pertechnetate anoin sorption on tin-bentonite is a (Sn(II/IV)-TcO4-) redox reaction. Thus, Sn-bentonite can be a suitable sorbent for radioactive waste management.

Analysis of Micro-Contaminants in Solid Particles from Direct Injection Gasoline Vehicles

Exhaust emissions from vehicles are the subject of numerous studies and legal acts. In the European Union, exhaust emissions are regulated by “Euro” emission standards, which limit emissions of gaseous pollutants such as CO, CO2, HC, and NOx, as well as the particulate matter (PM) and particle number (PN). Solid particles consist of a number of micro-contaminants, inter alia polycyclic aromatic hydrocarbons (PAHs) and their nitrated and oxygenated derivatives. Despite their highly mutagenic and carcinogenic character, these micro-contaminants are not regulated in Euro emissions standards. This paper presents both a general discussion of the phenomenon of particulate formation in and emission from direct injection gasoline engines, as well as a wide range of results on the subject. The subject of the micro-contaminants in solid particles from modern gasoline vehicles is explored. The samples of solid particles were collected from 11 groups of vehicles according to the WLTP test methodology. Solid particles from gasoline vehicles were analyzed via various analytical techniques, including ion chromatography (IC) to measure selected anion concentrations, gas chromatography with mass spectroscopy (GC-MS) to study 16 PAHs and selected PAH derivatives, scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS) for images and elemental composition, and microwave plasma atomic emission spectroscopy (MP-AES) for qualitative screening analysis of 19 elements. The study of non-regulated compounds is crucial in efforts to establish the influence of solid particles on health and the environment. Furthermore, extended studies can provide a basis for further research on vehicle emissions or other fields, such as medicine or material engineering.

Effect of microwave processing on Mn doped ZnO diluted magnetic semiconductor characteristics

5 and 7.5 at% Mn doped ZnO samples were prepared by microwave treatment following thermal curing. The XRD phase analysis reveals the Mn may be present in the unreacted Mn3O4 form or bonded with wurtzite ZnO forming substitutional solid solution (Zn0.99Mn0.01O and Zn0.95Mn0.05O) or spinel (ZnMn2O4). The Fourier transform infra-red (FTIR) band shift to higher wavenumber for the microwave treated samples appearing at 538 and 619 cm−1 indicates formation of ZnMn2O4 spinel structure. Identification of tiny particles in the wall of ZnO lamellae and decrease in Zn2p binding energy signifies vigorous chemical changes taken place on microwave treatment. The structural evolution was depicted by 3d modelling. Quantitative estimation of Mn in the samples was performed by microwave plasma atomic emission spectroscopy (MPAES) and the result matches with the calculated value. Raman spectroscopy shows clear peaks of ZnO, Mn3O4 and MnO2 compounds for all the samples prepared. Whereas, shoulder peak of ZnMn2O4 is observed for 7.5 at% Mn doped microwave pre-treated sample. The optical absorption spectra show major peak near to 360 nm signifying bandgap of ZnO in the visible range. The cation substitution in the host lattice by dopant creates oxygen vacancy (VO) in excess, responsible for increasing bound magnetic polaron, which is clearly evidenced by the presence of broad PL peak near to 535 nm and 548 nm for microwave treated samples. The microwave treatment assists the incorporation of Mn into ZnO lattice as evidenced by reduction of photoluminescence (PL) peak intensity. The magnetic hysteresis loop (B-H curve) of the samples clearly shows increase in saturation magnetisation by ~16.1 and ~24.7 % on microwave treatment of 5 and 7.5 at% Mn doped ZnO respectively.

Oxygen reduction reaction on PdM/C (M = Pb, Sn, Bi) alloy nanocatalysts

In this work three PdM/C bimetallic catalysts were prepared with a second metal being either Bi, Pb or Sn. The synthesised Pd-alloy nanoparticles were supported on Vulcan carbon XC-72R. These catalysts were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HR-TEM) and electrochemically using the rotating disk electrode (RDE) technique. The prepared Pd-based electrocatalysts were compared to pure Pd/C catalyst synthesised using the citrate method. The oxygen reduction reaction (ORR) kinetics on Pd-alloy catalysts in alkaline solution was systematically investigated. Pd content was determined by microwave plasma atomic emission spectroscopy, which was used to calculate the mass activities (MA) for ORR. Mass activities revealed that BiPd had two-fold higher and PbPd showed 1.6-times increase in MA as compared to Pd/C, however SnPd showed lower MA than Pd/C. BiPd/C catalyst showed around 45% increase in specific activity (SA) for ORR, PdSn catalyst showed around 25% increase and PbPd no increase in SA in comparison to the Pd/C catalyst. Methanol tolerance was also studied for the PdM/C alloy catalysts and a higher tolerance was observed for BiPd/C losing 17 mV in the half-wave potential value and even better methanol tolerance was in evidence with the other two catalysts that lost only ∼10 mV in 0.1 M KOH + 0.5 M MeOH.

Assessment of fatty acids, amino acids, minerals, and thermal properties of bee propolis from Northern India using a multivariate approach

First-ever, the propolis samples collected from different geographical locations of Northern India were investigated based on nutritional composition and thermal analysis. Gas chromatograph flame ionization detector (GC-FID) identified the presence of essential fatty acids: linoleic acid, α-linolenic acid, cis-11,14,17-eicosatrienoic acid, eicosapentaenoic acid, docosahexaenoic acid, γ-linolenic acid, dihomo-γ-linolenic acid, and cis-11–14-eicosadienoic acid in the samples. Additionally, first-time detection of 17 amino acids showed the presences of tyrosine, glutamic acid, threonine, arginine, lysine and aspartic acid as predominant in the samples, whereas microwave plasma-atomic emission spectroscopy (MP-AES) revealed abundance of calcium (5706.2–3121.0 mg/kg) followed by potassium (2636.0–1615.5 mg/kg), iron (2487.0–1161.2 mg/kg) and magnesium (1573.4–841.0 mg/kg). Furthermore, differential scanning calorimetry (DSC) showed major endothermic peaks at approximately 60 ᵒC demonstrating melting of long and medium chain fatty acids especially beeswax and palmitic acid, while the secondary peaks exposed vaporization of aromatic compounds. Thermogravimetric analyzer (TGA) depicted major weight loss of propolis between 270 and 470 °C and obtained 14.99–40.02% residual weight. Principal Component analysis demonstrated 99.18% variation in the first three principal components. Hierarchical cluster analysis categorized all the propolis samples successfully based on geographical locations. This study may assist quality control authorities to establish nutritional and quality standards of Indian propolis in future.

Esterification of Levulinic Acid to Methyl Levulinate over Zr-MOFs Catalysts

At present, the trend towards partial replacement of petroleum-derived fuels by those from the revaluation of biomass has become of great importance. An effective strategy for processing complex biomass feedstocks involves prior conversion to simpler compounds (platform molecules) that are more easily transformed in subsequent reactions. This study analyzes the metal–organic frameworks (MOFs) that contain Zr metal clusters formed by ligands of terephthalic acid (UiO-66) and aminoterephthalic acid (UiO-66-NH2), as active and stable catalysts for the esterification of levulinic acid with methanol. An alternative synthesis is presented by means of ultrasonic stirring at room temperature and 60 °C, in order to improve the structural properties of the catalysts. They were analyzed by X-ray diffraction, scanning electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, microwave plasma atomic emission spectroscopy, acidity measurement, and N2 adsorption. The catalytic reaction was carried out in a batch system and under pressure in an autoclave. Its progress was followed by gas chromatography and mass spectrometry. Parameters such as temperature, catalyst mass, and molar ratio of reactants were optimized to improve the catalytic performance. The MOF that presented the highest activity and selectivity to the desired product was obtained by synthesis with ultrasound and 60 °C with aminoterephthalic acid. The methyl levulinate yield was 67.77% in batch at 5 h and 85.89% in an autoclave at 1 h. An analysis of the kinetic parameters of the reaction is presented. The spent material can be activated by ethanol washing allowing the catalytic activity to be maintained in the recycles.

Enhancing the Spectroelectrochemical Performance of WO3 Films by Use of Structure-Directing Agents during Film Growth

Thin, porous films of WO3 were fabricated by solution-based synthesis via spin-coating using polyethylene glycol (PEG), a block copolymer (PIB50-b-PEO45), or a combination of PEG and PIB50-b-PEO45 as structure-directing agents. The influence of the polymers on the composition and porosity of WO3 was investigated by microwave plasma atomic emission spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, X-ray diffraction, and gas sorption analysis. The electrochromic performance of the WO3 thin films was characterized with LiClO4 in propylene carbonate as electrolyte. To analyze the intercalation of the Li+ ions, time-of-flight secondary ion mass spectrometry, and X-ray photoelectron spectroscopy were performed on films in a pristine or reduced state. The use of PEG led to networks of micropores allowing fast reversible electrochromic switching with a high modulation of the optical transmittance and a high coloration efficiency. The use of PIB50-b-PEO45 provided isolated spherical mesopores leading to an electrochromic performance similar to compact WO3, only. Optimum characteristics were obtained in films which had been prepared in the presence of both, PEG and PIB50-b-PEO45, since WO3 films with mesopores were obtained that were interconnected by a microporous network and showed a clear progress in electrochromic switching beyond compact or microporous WO3.

Heavy metal impression in surface sediments and factors governing the fate of macrobenthic communties in tropical estuarine ecosystem, India.

The present study aims to investigate the contamination of heavy metals in the sediments of a tropical ecosystem, India, and to evaluate the factors responsible for the dominance of specific macrobenthic communities, particularly in estuarine sediments. For the analysis of Cu, Cr, Ni, Zn, Pb and Cd in sediments, acid digestion and subsequent quantification by microwave plasma atomic emission spectroscopy was performed, whereas for Hg determination, cold vapour atomic absorption spectrophotometry was used. The general trend of the heavy metal concentration was observed as Cr > Cu > Zn > Ni > Pb > Cd > Hg, regardless of any seasonal alteration. The estuarine region was considerably contaminated by Cu and Cr (C.F. > 2) irrespective of any seasonal difference, and by Cd in 2017 non-monsoon (CF > 3). Heavy metal contamination was most pronounced during the monsoon (2018). Estuarine and marine zone together considered as deteriorated zone especially during monsoon seasons (PLI > 1, 2018 monsoon) while riverine zone remained poorly contaminated (PLI < 1). Clay Loam/Clay/Heavy Clay textures preferred polychaetes and bivalves in the estuarine and marine zone as compared to other macrobenthic communities (OMC). Among the hydrochemical parameters, total dissolved solids in general and euryhaline and slightly alkaline pH preferred domination of bivalves followed by polychaetes in non-monsoon seasons. The trace metal contamination in estuarine sediments increases the concern of bioaccumulation tendency of dominant bivalves of the estuarine and coastal sediments.

Heavy Metal Concentration And Health Risk Assessment In Soil, Vegetables, And Water Of Central Rift Valley, Ethiopia

Background Several heavy metals are toxic to organisms including human and therefore their entry into food chain from polluted agricultural land is required to be controlled. The objective of this study was to investigate the impact of industrialization on the quality of agricultural products and environments in the area of the central rift valley, Ethiopia. The samples of soils, water, and vegetables were randomly collected, processed, and analyzed for heavy metals using microwave plasma atomic emission spectroscopy (MPAES). Also, it examines potential health risks from the consumption of these vegetables. Results The result shown the average concentration gradient of metals in the soil, water, and vegetables (ppm) was Ni&lt;Co&lt; Cd&lt;Pb&lt;Cu&lt;Cr&lt;Zn&lt;Mn&lt;Fe. According to the statistics, Pearson cross-correlation analysis results for the element pairs of CoNi (0.879), Cr-Cu (0.582), Fe-Cr (0.597), Fe-Cu (0.581), Fe-Pb (0.587) and Fe-Cu (0.694) were showed the highest and positive. Metals with the highest positive correlations indicated that the same behavior in the environment, increasing or decreasing together in the environment. The correlations obtained between Cr-Mn, Cr-Zn, Cu-Mn, Cu-Zn, Mn-PB, and Ni-Zn was the moderately highest among the others. The moderately high correlations between these metals indicated that the pollutants possibly shared the same source, whereas the others may have arisen from individual sources in the region. Moreover, the soil concentrations of Fe, Mn, Zn, and Cr were also high and higher compared with the level of different countries' standards. The average daily intake for Pb(7.79), Fe(2755.38), Zn(55.83) and Cu(639.05) mg/person/day were above the permissible maximum tolerable daily intake of 0.21, 15, 15, 2.0mg/person/day endorsed by WHO/FAO. Hazard quotient of Pb, Fe, Zn, Zn, Mn and Cu as well as the hazard indices of selected vegetables were exceeded unity, signifying presence of health risks from consumption of the vegetables. Conclusion Based on the results of this study, heavy metals had a significant health risk (both non-carcinogenic and carcinogenic) effects to the consumer associated with the consumption of these vegetables grown within the study area. Consequently, we recommend a strict regulatory control on the safety of vegetables originated from the study area and food chain.

Synthesis, Characterization and Catalytic Activity of UiO-66-NH2 in the Esterification of Levulinic Acid

The massive use of petroleum and its possible exhaustion are driving the current research trend to study alternative raw materials from biomass for organic reactions. In this context, the present article presents a study of the catalytic esterification of levulinic acid, a platform molecule, with ethanol. Metal-organic framework (MOF) type compounds UiO-66-NH2 have been synthesized. Zirconium was incorporated, using zirconium chloride as a metal precursor, together with 2-aminoterephthalic acid as an organic binding agent. An alternative route of synthesis was proposed using more favorable conditions from an economic and environmental point of view, replacing dimethylformamide by 50 and 75% acetone as substitute solvent. The physicochemical properties of the materials were evaluated by X-ray diffraction (XRD), Infrared Spectrometry with Fourier Transform (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), microwave plasma atomic emission spectroscopy (MP-AES) and N2 adsorption to understand their morphology, crystalline, chemical and pore structure. The progress of the reaction was followed by gas chromatography and mass spectroscopy. The catalytic activity result of MOF25% in autoclave reactor, showed 100% of selectivity to ethyl levulinate and a turnover number (TON) of 66.18 moles of product/moles of Zr. This good catalytic performance obtained by partial solvent replacement in the synthetic material provides a more economical and eco-friendly process for ethyl levulinate generation.

Assessment of metals content of widely used traditional toothbrushes in Addis Ababa, Ethiopia

ABSTRACT. Traditional toothbrushes are used by the vast majority of people who cannot afford to buy the commercial toothbrush and toothpaste. The traditional toothbrushes are generally obtained from any slim woody part of a toothbrush tree. The main purpose of this study was to determine selected metals (Ca, Fe, Mg, Al, Cu, Cr, Ni, Zn, Mn, Pb, and Cd) in traditional toothbrushes obtained from three plants including Ligustrum vulgare L., Phoenix reclinata and Olea africana, which are extensively used in Addis Ababa, Ethiopia, by using microwave plasma-atomic emission spectroscopy (MP-AES) after wet digestion. Recoveries of the metals in spiked samples varied from 90.4–107%. The overall mean concentrations determined (mg/kg, dry weight) were in the ranges of Ca (4267–36514) &gt; Fe (131–318) &gt; Al (81.6 –224) &gt; Mg (45.6–122) &gt; Zn (27.2–175) &gt; Mn (20.1–29) &gt; Cu (6.6–20.3) &gt; Cr (6.7–8.9) &gt; Ni (2.6–7.9). Analysis of variance at 95% indicated significant differences in the metals’ contents of three toothbrushes. The results indicated that the selected traditional toothbrushes are good sources of essential metals and free from Pb and Cd. Therefore, the investigated Ethiopian traditional toothbrushes are found to be safe for human use.&#x0D; &#x0D; KEY WORDS: Metal contents, Traditional toothbrushes, Wild privet (Ligustrum vulgare), Wild date palm (Phoenix reclinata), African wild olive (Olea africana), Ethiopia&#x0D; &#x0D; Bull. Chem. Soc. Ethiop. 2021, 35(2), 257-272.&#x0D; DOI: https://dx.doi.org/10.4314/bcse.v35i2.4

Levels of selected metals in the fruits of a wild edible plant (Rubus steudneri Schweinf) and its underlying soil

ABSTRACT. This study was focused on investigation of amount of macro and trace metals present in the fruit samples of Rubus steudneri Schweinf plant and its underlying soil samples collected from Chencha, Dega Damot and Fiche areas of Ethiopia. The levels of selected metals (K, Ca, Mg, Fe, Mn, Zn, Cu, Cd, and Pb) were determined by microwave plasma-atomic emission spectroscopy using wet-digestion technique. The validity of the method was checked by the analysis of spiked samples whose recovery was found in the range of 90.5-108%. The mean concentration of metals K, Mg, Fe, Ca, Zn, Cu, Mn, Pb and Cd in the fruit samples were found in the range of 9463-9836, 973-1099, 328-639, 2663-2999, 29.6-52.8, 6.70-8.87, 128-639, 2.54-3.37 and 0.26-1.21 mg/kg, respectively. The level of metals in the soil samples were found in the range of 1375-1790, 1169-1388, 74951-104145, 2079-3502, 122-149, 21.6-40.4, 1359-1931, 7.11-17.0 and ND mg/kg, respectively. The accumulation factor values for the tested metals were found in the range of 0.003 (Fe) - 7.07 (K). The Rubus steudneri Schweinf fruit is good source of essential metals and useful to human health. However, the concentration of toxic metals viz. Cd and Pb were found in amount excess as compared to WHO/FAO maximum permissible limit.&#x0D; &#x0D; KEY WORDS: Rubus steudneri Schweinf, Wild edible plant, Fruit, Heavy metals, Soil, Ethiopia&#x0D; &#x0D; Bull. Chem. Soc. Ethiop. 2021, 35(2), 217-228.&#x0D; DOI: https://dx.doi.org/10.4314/bcse.v35i2.1

Macro and trace elements in the black pine needles as inorganic indicators of urban traffic emissions

Urban activities intensify air pollution by increasing the amount of particulate matter (PM). The trees collect PM by adsorption on the leaf surface and simultaneously absorb inorganic components. In this research, we investigated the potential of the black pine as bioindicator of road traffic emissions in Cluj-Napoca (Romania). We defined three sites types with different exposure to the road traffic (streets, outskirts, parks) and a control site far from the city. We quantified 17 inorganic components (Al, B, Ba, Ca, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, Sr, Zn) by MP-AES (microwave-plasma atomic emission spectroscopy) technique in the one-year-old needles and we identified the best candidates for biomonitoring purposes.The concentration of Ba, Cr, Cu and Fe showed the most sensitive variations with the road traffic intensity. While in the streets the Ba, Cu and Fe increased by 2.8–3.5 times in relation to the control site, the Cr varied in the highest degree exhibiting ratios of 2.2 (parks), 3.3 (outskirts) and 6.3 (streets). The success of these elements lies in several characteristics: they are closely related to non-exhaust emissions, they are readily absorbed through the leaves rather than the roots, and they tend to accumulate in the needles instead of being relocated to other organs. The street maintenance activities caused considerable accumulation of Na in the trees from the roadsides, but had no impact over the trees from the parks. The elements originating mainly in the re-suspended urban dust (Ni, Pb, Sr) equally affected the pines from the streets and parks.

Chitosan Functionalized with 2-Methylpyridine Cross-Linker Cellulose to Adsorb Pb(II) from Water.

In this study, chitosan was chemically modified with 2-methylpyridine. Subsequently, the modified chitosan was cross-linked to cellulose using succinic anhydride. Additionally, the capacity of cellulose derivatives to adsorb Pb(II) ions in an aqueous solution was studied through the determination of Pb(II) ions concentration in water, using microwave plasma atomic emission spectroscopy (MP-AES). A maximum adsorption capacity of 6.62, 43.14, 60.6, and 80.26 mg/g was found for cellulose, cellulose-succinic acid, cellulose-chitosan, and cellulose-chitosan-pyridine, respectively. The kinetic data analysis of the adsorption process showed a pseudo-second-order behavior. The increase in metal removal from water is possibly due to metal chelation with the carbonyl group of succinic acid, and the pyridine groups incorporated into chitosan.

Correlating ZnSe Quantum Dot Absorption with Particle Size and Concentration.

The focus on heavy metal-free semiconductor nanocrystals has increased interest in ZnSe semiconductor quantum dots (QDs) over the past decade. Reliable and consistent incorporation of ZnSe cores into core/shell heterostructures or devices requires empirical fit equations correlating the lowest-energy electron transition (1S peak) to their size and molar extinction coefficients (ε). While these equations are known and heavily used for CdSe, CdTe, CdS, PbS, etc., they are not well established for ZnSe and are nonexistent for ZnSe QDs with diameters <3.5 nm. In this study, a series of ZnSe QDs with diameters ranging from 2 to 6 nm were characterized by small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), UV-vis spectroscopy, and microwave plasma atomic emission spectroscopy (MP-AES). SAXS-based size analysis enabled the practical inclusion of small particles in the evaluation, and elemental analysis with MP-AES elucidates a nonstoichiometric Zn:Se ratio consistent with zinc-terminated spherical ZnSe QDs. Using these combined results, empirical fit equations correlating QD size with its lowest-energy electron transition (i.e., 1S peak position), Zn:Se ratio, and molar extinction coefficients for 1S peak, 1S integral, and high-energy wavelengths are reported. Finally, the equations are used to track the evolution of a ZnSe core reaction. These results will enable the consistent and reliable use of ZnSe core particles in complex heterostructures and devices.

Fast Fluorescence Titration Quantification of Plasmid DNA with DNA Attractive Magnetic Nanoparticles.

Fluorescence titration using magnetic nanoparticles (FTMN) was performed as a rapid, inexpensive, and simple method for quantifying the amount of fluorophore-intercalated plasmid DNA on these DNA attractive nanoparticles. Binding of the propidium iodide (PI)-intercalated DNA (PI/DNA) to polyethylenimine (PEI)-coated monodisperse iron oxide magnetic nanoparticles (PEI-MNs) was confirmed with transmission electron microscopy after the two species were mixed in water for less than a minute. The amount of DNA on PEI-MNs in aqueous solution, however, could not be easily determined using direct fluorescence measurements due to strong scattering by aggregated MNs, especially at high nanoparticle concentrations. Instead, fluorescence measurements were taken immediately after the solution of PI/DNA and PEI-MN mixtures was treated with a magnet to pull the PEI-MNs out of the solution. The detected fluorescence signal of the remaining free PI/DNA in the solution decreased as the concentration of PEI-MNs in the pre-treated solutions increased, resulting in a titration curve, which was used to determine the amount of DNA on MNs, the dissociation constant, and binding energy after the concentration of PEI-MNs was calibrated with microwave-plasma atomic emission spectroscopy. Quantitative polymerase chain reaction was used to understand the binding of DNA to MNs and to measure the amount of free PI/DNA in solution, and the results were similar to those obtained with the FTMN method.