Atomic Absorption Spectroscopy Analysis Research Articles

Synthesis and characterization of a single-walled carbon nanotubes/l-cysteine/Nafion-ionic liquid nanocomposite and its application in the ultrasensitive determination of Cd(II) and Pb(II)

In this paper, an electrochemical sensor was fabricated for the sensitive and simultaneous analysis of Pb(II) and Cd(II) by the modification of glassy carbon electrodes (GCEs) with a dispersion of l-cysteine-functionalized single-walled carbon nanotubes (SWCNs) incorporating Nafion and ionic liquid (IL) (SWCNs/l-cysteine/Nafion-IL/GCE). The SWCNs were functionalized by the covalent interaction between the −NH3 groups of l-cysteine and −COOH groups of pyrene carboxylic acid (PCA), and this interaction was activated by N-ethyl-N′(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide (NHS). The modification of PCA on the SWCNs was realized by noncovalent π–π stacking interactions between the PCA molecules and SWCNs. The prepared nanocomposite was characterized by square-wave anodic stripping voltammetry (SWASV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and cyclic voltammetry (CV). By combining the outstanding adsorption capacity of l-cysteine and Nafion toward Pb(II) and Cd(II) with the advantages of SWCNs and ILs, the modified SWCNs/l-cysteine/Nafion-IL/GCE composite showed excellent detection performance, including good stability, high sensitivity and selectivity. Under the optimal conditions, the concentration of target heavy metals (HMs) was significantly linear with corresponding stripping currents for Pb(II) and Cd(II) in the concentration range of 0–50 μg L−1. The limits of detection for Cd(II) and Pb(II) were 0.05 μg L−1 and 0.08 μg L−1, respectively. Finally, SWCNs/l-cysteine/Nafion-IL/GCEs were successfully applied in the determination of Pb(II) and Cd(II) in real samples, and the results were compared with those of an atomic absorption spectrometry (AAS) analysis.

Anchoring of triethanolamine–Cu(II) complex on magnetic carbon nanotube as a promising recyclable catalyst for the synthesis of 5-substituted 1H-tetrazoles from aldehydes

The development of heterogenization of copper nanoparticles on conductive supports is very challenging and has received much attention. Here, we synthesize a practical, efficient, and inexpensive heterogeneous catalyst to grow stable metallic copper(II) nanoparticles on the surface of magnetic carbon nanotube (Fe3O4-CNT) catalyst support physically functionalized with triethanolamine (TEA) that acts as a low-cost and non-toxic ligand to capture the copper nanoparticles [Fe3O4-CNT-TEA-Cu(II)]. The as-prepared heterogeneous catalyst was characterized by different techniques, such as Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, vibrating sample magnetometer, X-ray diffraction patterns, field-emission scanning electron microscopy, and atomic absorption spectroscopy analysis. The catalytic behavior of Fe3O4-CNT-TEA-Cu(II) was investigated in the preparation of 5-substituted 1H-tetrazole derivatives via one-pot, three-component reaction between aromatic aldehydes, hydroxylamine, and sodium azide. The low catalyst loading, wide substrate scope, use of inexpensive materials, simple separation of the catalyst from the reaction mixture by an external magnet, short reaction times, easy workup, affordability, and superb yield are some advantages of this protocol.

Development of a very simple and fast analytical methodology for FAAS/FAES measurements of Ca, K, Mg and Na in red beetroot juices along with chemical fractionation of Ca and Mg by solid phase extraction

A new simplified method of flame atomic absorption and emission spectrometry (FAAS/FAES) analysis of red beetroot juices on the content of Ca, K, Mg, and Na was proposed and validated. The method included only appropriate dilution of samples with 0.5 mol L−1 HNO3 prior to spectrometric measurements and was characterized by precision better than 2% and trueness better than 3%. It was used to verify quality of twelve commercially available red beetroot juices. In addition, chemical fractionation of Ca and Mg was undertaken with the aid of tandem solid phase extraction (SPE) with reversed phase and cation exchange sorptive materials. Three operationally defined fractions, including hydrophobic, residual, and cationic species, were distinguished. On the basis of contributions of these fractions it was presumed that Ca and Mg were organically bound to a high degree, i.e., on average 86% in case of Ca and 75% in case of Mg.

Assessing Mercury Mobility in Sediment of the Union Canal, Scotland, UK by Sequential Extraction and Thermal Desorption.

The mobility of mercury (Hg) was assessed in sediment from the Union Canal, Scotland, UK. Samples collected from the vicinity of a former munitions factory that manufactured mercury fulminate detonators were subjected to sequential extraction followed by cold vapor atomic absorption spectrometry (CVAAS) and direct analysis using thermal desorption (TD). The sequential extraction indicated that > 75% of mercury (up to 429mgkg-1) was in mobile forms, with < 12% semimobile and < 23% nonmobile species. In the TD method, > 67% of the total Hg content was desorbed in the temperature range 100-250°C consistent with species weakly attached to the mineral matrix [tentatively identified as an iron (oxy)hydroxide-associated species]. This predominance of mobile mercury species may arise from a lack of association between Hg and either organic matter or sulfur in the sediments. Further investigation of Hg mobilization, transport, and assimilation/biomagnification is required both to determine whether there is a need for remediation of the sediment and to improve understanding of the biogeochemical cycling of Hg in shallow, oxic, freshwater systems.

Development of magnetic porous coordination polymer adsorbent for the removal and preconcentration of Pb(II) from environmental water samples

A novel porous coordination polymer adsorbent (BTCA-P-Cu-CP) based on a piperazine(P) as a ligand and 1,2,4,5-benzenetetracarboxylic acid (BTCA) as a linker was synthesized and magnetized to form magnetic porous coordination polymer (BTCA-P-Cu-MCP). Fourier transform infrared (FTIR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), field emission scanning electron microscope(FESEM), energy-dispersive X-ray spectroscopy(EDS), CHN, and Brunauer-Emmett-Teller(BET) analysis were used to characterize the synthesized adsorbent. BTCA-P-Cu-MCP was used for removal and preconcentration of Pb(II) ions from environmental water samples prior to flame atomic absorption spectrometry(FAAS) analysis. The maximum adsorption capacity of BTCA-P-Cu-MCP was 582mgg-1. Adsorption isotherm, kinetic, and thermodynamic parameters were investigated for Pb(II) ions adsorption. Magnetic solid phase extraction (MSPE) method was used for preconcentration of Pb(II) ions and the parameters influencing the preconcentration process have been examined. The linearity range of proposed method was 0.1-100μgL-1 with a preconcentration factor of 100. The limits of detection and limits of quantification for lead were 0.03μgL-1 and 0.11μgL-1, respectively. The intra-day (n = 7) and inter-day (n = 3) relative standard deviations (RSDs) were 1.54 and 3.43% respectively. The recoveries from 94.75 ± 4 to 100.93 ± 1.9% were obtained for rapid extraction of trace levels of Pb(II) ions in different water samples. The results showed that the BTCA-P-Cu-MCP was steady and effective adsorbent for the decontamination and preconcentration of lead ions from the aqueous environment.

Aluminium release by coated and uncoated fluid-warming devices.

The use of fluid-warming systems is recommended for infusion rates >500ml.h-1 to avoid peri-operative hypothermia. Some fluid-warming devices use disposable aluminium-heated plates for heat transfer, but there is no protective coating to separate the fluid from the heated aluminium surface. It is unknown if this could promote release of aluminium into infusion fluids. We investigated a coated (Fluido compact) and an uncoated (enFlow) fluid-warming device using normal saline or balanced electrolyte solution as infusion fluids, pumped through the heated disposables at flow rates of 2, 4 and 8ml.min-1 for 60min each. Aluminium concentrations in the fluid samples were analysed using graphite furnace atomic absorption spectrometry. With saline the coated and uncoated devices yielded aluminium concentrations below the level of quantification (<128μg.l-1 ). Similarly, balanced electrolyte solution in the coated device yielded aluminium concentrations <128μg.l-1 . However, balanced electrolyte solution in the uncoated device yielded aluminium concentrations of up to 6794 (3465-8002 [1868-7421]) μg.l-1 . Repeating this last study at a flow rate of 2ml.min-1 resulted in quite high aluminium concentrations when the uncoated device was not heated (~1000μg.l-1 ) and higher concentrations after the device was heated. We conclude that using uncoated aluminium plates in fluid-warming systems can lead to a risk of administering potentially harmful concentrations of aluminium when balanced crystalloid solutions are used. The mechanism is unclear, but heat is in part involved. Coating for aluminium within medical devices in direct contact with infusion fluids should be recommended.

Cadmium tolerance is associated with the root-driven coordination of cadmium sequestration, iron regulation, and ROS scavenging in rice

Excess cadmium (Cd) is a serious threat to agriculture and the environment. High Cd availability showed no significant decline in growth, chlorophyll synthesis, soluble protein, cell and membrane stability in Sonarbangla (Cd-tolerant), while these were severely affected in BRRI 72 (Cd-sensitive). Atomic absorption spectroscopy analysis demonstrated a huge increment of Cd and Fe in root and shoot of BRRI 72; however, Sonarbangla only exhibited a significant increase of Cd in roots. It suggests that excess Cd in Sonarbangla possibly retained in roots through vacuolar sequestration without interfering cell functions. This was further confirmed by the increased accumulation of cysteine, glutathione, and phytochelatin along with OsPCS1 and OsHMA3 upregulation, possibly facilitated by nitric oxide in roots of Sonarbangla. Further, Fe chelate reductase activity in conjunction with the genes (OsFRO1, OsNRAMP1, OsIRT1, and OsYSL15) associated with Fe availability significantly upregulated in BRRI 72 but not in Sonarbangla in response to Cd. It advises that Fe acquisition and transport were tightly regulated in Cd-tolerant Sonarbangla. Furthermore, elevated CAT, APX, GR, NO in root along with shoot sugar helps rice plants to withstand Cd-induced oxidative damage. Finally, reciprocal grafting combining Sonarbangla rootstock with either BRRI 72 or Sonarbangla scion showed Sonarbangla type tolerance along with no changes of H2O2 and Fe reductase activity in roots under high Cd. It indicates that the signal inducing the responses to adjust Cd stress is originated in the root system. These messages deliver essential background for further breeding program to produce Cd-free rice.

Physical and Chemical Properties of Biodiesel Obtained from Amazon Sailfin Catfish (Pterygoplichthys pardalis) Biomass Oil

Amazon sailfin catfish (Pterygoplichthys pardalis) is considered one of the greatest threats to the biodiversity of continental aquatic systems, causing serious economic and environmental problems in the regions. In this work, the production of biodiesel from Amazon sailfin catfish biomass oil is studied. The physical and chemical properties of biofuel produced were evaluated under the specifications of the European standard EN-14214 by using gas chromatography-mass spectrometry, infrared spectroscopy, and atomic absorption spectrometry analyses. The results show that the biodiesel complies with all the specifications of the standard, except the content of polyunsaturated methyl esters. The yields obtained from oil and biodiesel were 9.67 and 90.71% (m/m), respectively. The methyl ester concentrations study identified 17 components where 47.003% m/m corresponded to methyl esters with saturated chains, whereas 34.394% m/m was attributed to monosaturated methyl esters and the remaining (18.624% m/m) to polysaturated methyl esters. Finally, mineral analysis by atomic absorption showed the absence of heavy metals Cd, Ni, and Pb, as well as low concentrations of Ni, Fe, Cu, and Zn, demonstrating that the quality of the fuel is not compromised. The study indicates the feasibility of manufacturing biodiesel using Amazon sailfin catfish biomass oil as a low-cost raw material. It represents an environmental option to mitigate a global problem of atmospheric pollution, and at the same time, it shows a commercial alternative to reduce the ecological impact caused by this fish in the diverse ecosystems to which it has spread. In addition, the great adaptability of this fish provides the possibility of a profitable process to have very high rates of reproduction and growth, allowing the generation of large amounts of biomass for the production of biodiesel.

Adjusting Porosity and Pore Radius of Electrodeposited ZnO Photoanodes

The optimization of the porosity and pore radius of ZnO for the application in dye-sensitized solar cells is essential to enhance the cell performance. Porous ZnO films were fabricated by electrodeposition in the presence of eosin Y or in combination with eosin B which was used as a structure directing agent (SDA) for the first time. The influence of the deposition time and the SDA concentration on film porosity and pore radius was characterized by a combined electrochemical and atomic absorption spectroscopy analysis, and confirmed by gas sorption, optical spectroscopy and scanning electron microscopy. The combination of eosin Y with eosin B as SDA results in porous ZnO films with larger pore radius compared to the films prepared with eosin Y only. The larger pores showed a significantly decreased diffusion impedance leading to an increased photocurrent less hindered by mass transport. Successful application of these new ZnO films in dye-sensitized solar cells confirmed improved pathways for large complex ions as redox shuttles through the ZnO pore structure.

Synthesis and Structural Investigation of Some Transition Metals Complexes of Benzimidazolium Bromide

The present work involves the synthesis of novel imidazolium salts of bromide in step-wise reactions which are started from preparation of 2,4-dimorpholine-6-(1H-benzimidazole-1-yl)-1,3,5-triazine (1) in potassium hydroxide and DMF solvent followed by substitution reactions with n-butyl bromide and n-octyl bromide to afford the new ligands names L1 = 1-(2,4-dimorpholino-1,3,5-triazine-2-yl)-3-butyl-1H-benzimidazol-3-ium bromide and L2 = 1-(2,4-dimorpholino-1,3,5-triazine-2-yl)-3-octyl-1Hbenimidazol-3-ium bromide. The new ligands were recrystallized from hot chloroform and the following of reactions completion were carried out by thin layer chromatography (TLC). The formula and structures of the two salts of benzimidazolium bromide were confirmed on the basis of measurements of (CHN) elemental analyses, FT-IR, NMR and EIMS spectroscopy. Furthermore the manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes were synthesized from the direct reactions of their hydrated metal salts in methanol with the solutions of the ligands in chloroform in 1:1 mole ratio and the analytical data of atomic absorption spectroscopy and elemental analyses revealed the proposed formula of the solid metal complexes. The data obtained from FT-IR, UV-Visible spectra, molar conductivity and magnetic susceptibility measurements confirmed the octahedral environment around cobalt(II) ion in [CoL(H2O)2Cl2] and the tetrahedral geometry was adopted for manganese(II) and zinc(II) ions. However the square-planner structure was expected for the copper(II) and nickel(II) complexes in [MLCl2], M = Ni(II) and Cu(II) ions and L = L1 and L2 ligands. As well as the suitable and favourable active sites in the two ligands L1 and L2 were the two nitrogen atoms of morpholine rings which has been observed from FT-IR spectra and the kinetic stability of five-member ring up on chelation with the metal ions supported the conclusion of the symmetry.

Synthesis of N-F-codoped TiO2/SiO2 nanocomposites as a visible and sunlight response photocatalyst for simultaneous degradation of organic water pollutants and reduction of Cr (VI)

A new N-F-codoped TiO2/SiO2 nanocomposite was prepared by simple sol-gel method, and strongly stabilized on a substrate used in a fabricated photoreactor. The prepared photocatalysts were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, diffuse reflectance UV/Vis, photoluminescence, field emission scanning electron microscope, energy dispersive X-ray, transmission electron microscope, and N2 adsorption/desorption methods. The effective parameters of pH, flow rate of the incoming current, and the photoreactor tubes angle against sunlight were optimized. The photocatalytic performance of prepared photocatalysts was evaluated by studying the simultaneous removal of a mixture containing three azo dyes and Cr (VI) in the fabricated continuous-flow photoreactor under visible and solar irradiation. The performance of the designed system was also proved under various outdoor climate conditions. Total organic carbon and flame atomic absorption spectroscopy analysis were performed on the treated sample to confirm the decontamination of the model pollutant mixture. It was found that doping N and F in TiO2/SiO2 nanoparticles caused least agglomeration, enhanced activity under visible and solar irradiation, and fully anatase crystalline structure in the as-synthesized nanoparticles.

Simultaneous determination of iron and nickel as contaminants in multimineral and multivitamin supplements by solid sampling HR-CS GF AAS

A methodology to assay simultaneously iron and nickel present as contaminants in multimineral and multivitamin supplements was investigated. High-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sample analysis were used. Measurements were done with the secondary lines of Fe (352.604 nm) and Ni (352.454 nm) to avoid spectral interferences. The best temperatures for pyrolysis and atomization for Fe and Ni were 1000 and 2700 °C, respectively. Chemical modifiers were not necessary and no matrix effects were observed. Aqueous standard solutions were used for calibration. The limit of detection was 0.517 µg g−1 for Fe and 0.011 µg g−1 for Ni. The precision ranged from 4.3% to 17% and 4.4–20% for Fe and Ni, respectively. The method accuracy was confirmed by comparing statistically the results obtained by solid sampling with those of sample acid digestion. The proposed methodology was successfully applied to determine both metals in different multimineral and multivitamin supplements.

Two Highly Stable Luminescent Lead Phosphonates Based on Mixed Ligands: Highly Selective and Sensitive Sensing for Thymine Molecule and VO3 - Anion.

Two luminescent lead phosphonates with two-dimensional (2D) layer and three-dimensional (3D) framework structure, namely, Pb3[(L1)2(Hssc)(H2O)2] (1) and [Pb2(L2)0.5(bts)(H2O)2]·H2O (2) (H2L1 = O(CH2CH2)2NCH2PO3H2, H4L2 = H2PO3CH2NH(C2H4)2NHCH2PO3H2, H3ssc = 5-sulfosalicylic acid, NaH2bts = 5-sulfoisophthalic acid sodium) have been prepared via hydrothermal techniques. The two compounds not only show excellent thermal stability but also remain intact in aqueous solution within an extensive pH range. Moreover, the atomic absorption spectroscopy analysis experiment indicates that there does not exist the leaching of Pb2+ ions from the lead phosphonates, which show they are nontoxic in aqueous solution. In compound 1, the Pb(1)O4, Pb(2)O7, Pb(3)O4, and CPO3 polyhedra are interlinked into a one-dimensional chain, which is further connected to adjacent chain by sharing the Hssc2– to form a 2D layer. Interestingly, compound 1 as a highly selective and sensitive luminescent material can be used to detect the thymine molecule with a very low detection limit of 8.26 × 10–7 M. In compound 2, the Pb(1)O6 and Pb(2)O5 polyhedra are interlinked into a dimer via edge sharing, which is further connected to adjacent dimer to form a tetramer via corner sharing, and such a tetramer is then interlinked into a 2D layer through bts3– ligands; the adjacent 2D layers are finally constructed to a 3D structure by sharing the L24– ligand. Compound 2 can be applied as an excellent luminescent sensor for sensing of VO3– anion. Furthermore, the probable fluorescent quenching mechanisms of the two compounds have also been studied.

A complementary experimental and in silico studies on the action of fluorophenyl‑2,2′‑bichalcophenes as ecofriendly corrosion inhibitors and biocide agents

The inhibition effect of fluorophenyl‑2,2′‑bichalcophenes on corrosion of carbon steel (C-steel) in 1.0 M hydrochloric acid (HCl) was investigated using various experimental techniques combined with quantum chemical calculations and atomistic modeling methodologies. Significant corrosion protection was demonstrated with the addition of the investigated inhibitors and 4‑([2,2′‑bithiophen]‑5‑yl)‑2‑fluorobenzamidine (MA-1156) exhibited very promising %IE (98%) at 18 × 10−6 M by Atomic Absorption Spectroscopy analysis. The studied compounds are classified as mixed-type inhibitors based on the potentiodynamic polarization results and the adsorption of compounds on C-steel surface was best described by Langmuir isotherm. The interaction of inhibitor compounds on Fe surface was deeply explored by Monte Carlo simulation in vacuum, water and acid solutions. The binding interaction of inhibitors was almost strengthened in acid solutions. In addition, the biocidal action of compounds against the growth of bacteria responsible for microbial influenced corrosion (MIC) was demonstrated. This served dual functions which would be beneficial from both an economic and environmental point of view.

Study on the chemical stability of the synthesized TiCx in Ti-Al-C system after immersion in the HF + H2O2 solution

The aim of this study is to investigate the phase stability of the prepared TiCx in Ti-Al-C system after immersion in the mixture of hydrofluoric acid (HF) and H2O2. The powders were immersed in the solution for different period times of 24, 48 and 96 h. The phase change of powders after different immersion times was studied by X-ray diffraction (XRD). The morphology evolution was detected by the field-emission scanning electron (FESEM). Moreover, atomic absorption spectroscopy (AAS) analysis was employed to study the changes in the chemical composition of solutions. The XRD results showed that by increasing the immersion time, gradually, the TiCx decomposed. It was also found that the selection oxidation aluminum occurred and the Al2O3 was the main final product of treatments. The FESEM images also confirmed the XRD results and after immersion of the powders into the solutions the rod-like and sheet-like morphology of the Al2O3 particles were obtained.

Development of Phosphatized Calcium Carbonate Biominerals as Bioactive Bone Graft Substitute Materials, Part II: Functionalization with Antibacterial Silver Ions

Porous calcium phosphate (CaP) materials as bone graft substitutes can be prepared from Ca carbonate biomineral structures by hydrothermal conversion into pseudomorphic CaP scaffolds. The present study aims at furnishing such phosphatized Ca carbonate biomineral (PCCB) materials with antibacterial Ag ions in order to avoid perisurgical wound infections. Prior to this study, PCCB materials with Mg and/or Sr ions incorporated for stimulating bone formation were prepared from coral skeletons and sea urchin spines as starting materials. The porous PCCB materials were treated with aqueous solutions of Ag nitrate with concentrations of 10 or 100 mmol/L, resulting in the formation of Ag phosphate nanoparticles on the sample surfaces through a replacement reaction. The materials were characterized using scanning electron microscopy (SEM) energy-dispersive X-ray spectroscopy (EDS) and X-ray diffractometry (XRD). In contact with Ringer`s solution, the Ag phosphate nanoparticles dissolved and released Ag ions with concentrations up to 0.51 mg/L, as shown by atomic absorption spectroscopy (AAS) analyses. In tests against Pseudomonas aeruginosa and Staphylococcus aureus on agar plates, antibacterial properties were similar for both types of Ag-modified PCCB materials. Concerning the antibacterial performance, the treatment with AgNO3 solutions with 10 mmol/L was almost as effective as with 100 mmol/L.

Determination of gold in microelectronic waste using atomic absorption spectroscopy and gravimetry

The procedures of gold determination in microelectronic waste using flame atomic absorption spectroscopy (FAAS) and gravimetric analysis are developed. The developed methods are used for gold determination in the waste of gold etching (KI + I 2 ) solution, technological mixture formed after cleaning vacuum deposition unit with aqua-regia solution as well as in a gold-containing powder obtained after reprocessing of liquid wastes. Optimum conditions for preparation and analysis of liquid and solid wastes having complex and variable matrix composition are specified. The FAAS methods of analysis provide determination of wastes in a wide range of gold concentration: in the solution for gold etching within the concentration range from 0.02 to 40 g/dm3, in the liquid phase of the technological mixture — from 0.1 to 30 g/dm3, in the solid phase of the technological mixture and in the gold-containing powder — from 3 to 80 wt. % with the relative error no more than ±5%. The gravimetric methods provide gold determination in the liquid phase of the technological mixture after gold reduction with hydrazine hedrochloride within the range of gold concentration from 0.5 to 500.0 g/dm3 with the relative error no more than ±1.3%. It is shown that the developed methods of analysis demonstrate good convergence of the results of analysis. The methods of analysis are certified by the Metrological Department of the enterprise and can be in a support technology of microelectronics production.

Chromium (VI) \u2013 induced stress response in the plant Plantago ovata Forsk in vitro

BackgroundPlants experience severe physiological stress from heavy metal pollution caused by improper discarding of the industrial wastes. Hexavalent chromium [Cr (VI)] is one of the major heavy metal pollutants in India and is present particularly in some regions where Plantago ovata grows to a great extent. This study was aimed at finding the effects of Cr (VI) on P. ovata and manoeuvres of the plant to combat such heavy metal exposure in vitro.MethodsPotassium dichromate was used as a source of Cr (VI) to induce the heavy metal stress. Range of Cr (VI) sublethal doses [0 mM (control), 0.1 mM, 0.3 mM, 0.5 mM, 1 mM, 1.5 mM and1.8 mM] was used to observe its effect on the plant. The seeds of the plant were grown on sucrose-agar media with different concentrations of potassium dichromate, and ten-day old seedlings were then harvested and examined.ResultsThe germination rate reduced below 50% at 1.9 mM Cr (VI) concentration and thus, 0 mM–1.8 mM concentration ranges were found to be suitable for sublethal dose. Morphological changes namely, reduction of the shoot-root length and multiple root development were caused by Cr (VI) in a dose-dependent manner. The plant showed elevated responses against Cr (VI), up to 1.5 mM (10 days treated) in terms of increasing accumulation of secondary metabolites like polyphenols, chlorophyll content (chlorophyll a, b and total chlorophyll), carotenoids and total antioxidant activity. DPPH radical scavenging activity along with malondialdehyde (MDA) content was not significantly elevated with the increase in Cr (VI) concentration indicating that the lipid peroxidation rate within the tissue was low. Phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO) gene expressions were upregulated by 1 mM Cr (VI) concentration, which decreased at higher concentrations. The atomic absorption spectroscopy analysis also showed significant accumulation of Cr (VI) in the shoot and root with an increase in the potassium dichromate concentration.ConclusionCr (VI) reduced the shoot-root length and seed germination in a dose-dependent manner. The plant system tried to combat the Cr (VI) stress by upregulating the stress response genes in the phenylpropanoid pathway along with an increase in polyphenol and antioxidant contents, which were evident from the lowering of lipid peroxidation rate and increase in PAL and PPO gene expressions.

A rapid ultrasonic energy assisted preconcentration method for simultaneous extraction of lead and cadmium in various cosmetic brands using deep eutectic solvent: A multivariate study

An innovative ultrasonic assisted microextraction method using a deep eutectic solvent for entrapping the organ metallic complexes was developed to pre-concentrate the trace quantities of cadmium (Cd) and lead (Pb) in lipsticks and eye shadows of different brands prior to flame atomic absorption spectrometry analysis. A deep eutectic solvent (DES) was used in this study, prepared by mixing metal salt (ZnCl2) and hydrogen bond donors such as (acetamide) in different ratio. The different branded cosmetic items, lipstick and eye shadows, obtained from local market and subjected to acid digestion prior to application of proposed ultrasonic assisted microextraction method based on deep eutectic solvent (UAµE-DES) with the aid of mechanical and ultrasound energies. Ammonium pyrrolidine dithiocarbamate was used as a ligand to made hydrophobic complexes of Cd and Pb, entrapped in DES in the presence of aprotic solvent. The seven variables, mixing ratio of ZnCl2 and Acetamide, DES volume, Ultrasound and Conventional shaking time, pH, tetrahydrofuran and complexing reagent volume were optimized by multivariate approach for the optimum recovery of Cd and Pb from real cosmetic items. The resulted data indicates that ultrasound energy assisted extraction time, volume of DES and pH were most significant variables. The precision and validity of developed procedure were checked by the spiked known certified standards in real samples. The resulted data indicated that the lipsticks have different glittering colors contains high contents of Pb and Cd, whereas dark colors of eye shadows contain high level of both elements.

Synthesis, characterization, and anticancer activity against human breast cancer cell-line T47D studies of metal ion Cu(II) complex with 2,4,5-triphenylimidazole ligand

The complex of metal ion Cu(II) with the ligand 2,4,5-trifenilimidazol has been successfully synthesized with mole ratio of metal and ligand 1:2 in N,N-dimethylformamide as a solvent. Complex synthesis results obtained green light crystalline solid. Complex absorbs UV-Vis light at 529 nm. Fourier transform infrared (FTIR) characterization results indicate occurrence of bonding of metals and ligand that is Cu-N in region 422.38 cm-1. Results of elemental analyzer and Atomic Absorption Spectroscopy (AAS) analysis show the complex formed has the formula [Cu(L)2(H2O)2].Cl2. The molecular formula is also supported by the Thermal Gravimetric Analyzer data. Thermal Gravimetric Analyzer (TGA) analysis results showed that there was no water in the crystalline complex compounds. The cytotoxicity test complex compounds made by the method of 3-(4,5-dimetiltiazol-2-yl)-2,5-difeniltetrazolium bromide (MTT) and the IC50 value of complex obtained 72.139 μg/ml. Key words: Copper(II), 2,4,5-trifenilimidazol, complex compound, characterization, anticancer.