Influence of Cr-doping on structural, magnetic and dielectric properties of M-type hexaferrites synthesized using microwave digestion technique

M-type hexaferrite SrCrxFe12-xO19 compounds doped with Cr (x=0, 1, 2, 3 and 4 at.%) were prepared by microwave digestion system. X-ray diffraction was used to study the structure and crystallization of the samples. The samples are found to have a hexagonal phase, SrFe12O19, as a main phase at 2Θ ≈ 33.144° and 35.618° for x = 0 and 1 respectively, and 32.451° and 34.295° for x ≥ 2. The Rietveld refined parameters such as the lattice parameters (a=b, c), direct and indirect cell volume, crystallite size and microstrain were investigated. TEM and SEM results showed that the samples have hexagonal shape and grain sizes range from 126 nm to 379 nm. Magnetization, M, as a function of the applied magnetic field, H, was obtained from the hysteresis loop. The coercive field, HC , saturation, Ms and remnant, Mr , magnetization and squareness ration, Mr/Ms , were extracted from the hysteresis loop results. These results revealed that HC is inversely proportional with the grains size of the samples but directly proportional with Cr-doping values candidating these compounds to be used in computer hard disk memories applications. M values are inversely proportional with Cr-doping values. The variation of conductivity, σ, impedance, Z, dielectric constant, ε, dielectric loss factor, tan δ and dissipation factor as functions of both AC frequency, F(Hz) and Cr-doping, x, were investigated. The maximum value of the dissipation factor was at x=2 which equals 8.05x109 m/F when F = 2x105 Hz. The impedance of the samples behaved as a capacitor reactance that makes our compounds candidate for many crucial dielectric applications.

Organ-specific accumulation of toxic elements in Hilsa shad (Tenualosa ilisha) from Bangladesh and human health risk assessment

Purpose: We aimed to determine the amount of some toxic elements in three organs of Hilsa shad, focusing on the possible exposure to human health through Hilsa consumption. This study was designed to determine the concentration of seven toxic trace elements (As, Cd, Cr, Cu, Ni, Pb, and Zn) in three distinct organs (n = 21) (muscle, liver, and gills) of Hilsa shad (Tenualosa ilisha) fish collected from the Bangladeshi coastal area. The samples were digested following a microwave digestion. Inductively coupled plasma mass spectrometer was used as analytical instrument. Estimated daily intakes (EDI) and target cancer risk (TR) were used to evaluate carcinogenic and non-carcinogenic risk. Results: The mean concentrations (mg/kg-wet weight) of toxic elements in different organs of T. ilisha were determined as follows: in muscle, As (4.05), Cd (0.09), Cr (0.12), Cu (0.77), Ni (0.26), Pb (0.20), and Zn (10.64); in liver, As (2.83), Cd (0.84), Cr (0.18), Cu (6.17), Ni (0.55), Pb (0.23), and Zn (30.16) and in gills, As (3.45), Cd (0.05), Cr (0.08), Cu (1.06), Ni (0.51), Pb (0.78), and Zn (35.21). The liver showed higher concentrations of most elements than that of muscle except for As. Concentration of As, Cd, and Pb in the fish were found above the food safety guidelines, while other trace element concentrations were below the permissible range for human consumption. According to EDI and TR values, there were carcinogenic and non-carcinogenic risks from exposure to total As concentration from Hilsa fish consumption. Conclusion: This study suggests that the toxic trace elements contamination levels in Hilsa fish from Bangladesh’s coastal area need to be monitored on a systematic and regular basis to ensure the safety of this food item for human consumption.

The Absorption, Distribution, and Excretion of 18 Elements of Tibetan Medicine Qishiwei Zhenzhu Pills in Rats with Cerebral Ischemia

The aim of this study is to determine 18 elements in Tibetan medicine Qishiwei Zhenzhu pills (QSW) and their absorption, distribution, and excretion in rats with cerebral ischemia. Microwave digestion and inductively coupled plasma mass spectrometry (ICP-MS) were used to determine 18 elements of QSW in simulated gastrointestinal (GI) juice. Rats were given QSW (66.68 mg/kg) followed by middle cerebral artery occlusion (MCAO). Sham rats received saline and were not subjected to MCAO. ICP-MS was applied to determine the content of 18 elements in hepatic venous blood, abdominal aortic blood, brain, liver, kidney, hair, urine, and feces 24 h after MCAO. In vitro results showed that the extraction rate of Mn, Cu, Sr, Pb, Au, and Hg of QSW in gastric juice (1 h) was higher than that in water, and the contents of Cu, Au, Sr, and As were higher in intestinal juice (4 h) than in water. In vivo results showed that the contents of elements in the blood were quite low, and QSW increased Ni, Cr, Sr, Co, and V in artery blood and decreased V in venous blood. Elements in the tissues were also low, and QSW increased brain Li but decreased Cr and Cd; QSW increased kidney Ag and Cs and liver Mn but decreased liver Ni. QSW increased urinary excretion of Li, Sr, Hg, Cs, and V; QSW increased Hg content in hair but decreased Ni. Stool is the main excretion pathway of the elements in QSW, with Ba, Mn, Sr, Cd, V, Cu, Cs, Li, Pb, Ag, Hg, Cr, As, and Co the highest. In summary, this study examined the distribution of 18 elements in QSW-treated MCAO rats. The accumulation of these elements in blood and tissues was extremely low, and the majority was excreted in feces within 24 h, highlighting the importance of the gut-microbiota-brain axis in QSW-mediated brain protection.

One-factor-at-a-time method combined with ICP-MS for determining 11 elements in soy sauce and their migration from the containing glass bottles

This study was designed to determine the 11 metal elements (Al, Cr, Mn, Fe, As, Ni, Cu, Zn, Cd, Sb, and Pb) in soy sauce and their migration from the containing glass bottles. Inductively coupled plasma mass spectrometry (ICP-MS) was applied for the determination of the elements and one-factor-at-a-time method was employed for optimizing the ICP-MS parameters in migration experiment and microwave digestion experiment. The developed method was successfully applied to determine the content of 11 elements. The results showed that the experiment had excellent correlation and sensitivity. The accuracy of the elements in the migration study and test of soy sauce itself ranging from 84.25% to 118.75% was satisfied, and the precision of the method was validated and the RSD was no more than 15.5%. The concentration of all the detected metal elements migrated from the glass bottles were between 0.3450 and 2.398 ng·mL−1, and the risk assessment indicated that the metal elements in soy sauce had no risk to the public health. The proposed methodology in this study was successfully applied for the quality control for metal elements in soy sauce and the containing glass bottles for the first time, and a research method suitable for soy sauce consumption process control and risk assessment has been established.

Chemical characterization methods for biodegradable organic wastes with relevance for the composting process. Case study

The study aimed to develop some methods for the compositional characterization of biodegradable waste with relevance to the composting process at the laboratory level. For testing, four waste fractions were selected, such as waste-based on dehydrated sludge, waste from parks (leaves, branches), market waste (mixture of vegetable and fruit), and cardboard waste. For metals and phosphorus, several microwave digestion methods were applied. The ammonium nitrogen content (NH4-N) was determined using a number of extraction procedures (water, CaCl2, and KCl). Three certified reference materials were used for testing the validity of the results. Recovery percentages higher than 90% were obtained. The developed and validated methods are suitable for biodegradable waste characterization used in composting processes.

Determination of Rare Earth Elements in Plant Samples by ICP-MS with Microwave Digestion

Method of microwave digestion using HNO3, HCl and HF in MARS‑5 system followed by ICP-MS analysis is proposed for determination of rare earth elements (REE) in plant materials. Limits of detection are 0.0001–0.001 ppm and allow for determination of all REE in certified reference materials Tr‑1, LB‑1 and EK‑1 and new reference material NSP‑1, relative standard deviations are lower than 13 %.Influence of HF addition during microwave digestion in UltraWAVE system on the ICP-MS analysis of REE in plant materials depending on silica content is studied. Necessity of HF addition during microwave digestion for better REE recoveries is shown for plant materials with Si contents exceeding 0.1 %

Protein Binding of a Novel Platinum-Based Anticancer Agent BP-C1 Containing a Lignin-Derived Polymeric Ligand

Platinum (Pt) antineoplastic agents remain indispensable for the treatment of oncological disease. Pt-based drugs are mainly used in the therapy of ovarian cancer and non-small-cell lung carcinoma. A novel platinum-containing antineoplastic agent BP-C1 is a complex of diamminoplatinum with an oxygen-donor polymeric ligand of benzene-polycarboxylic acids, isolated from natural lignin. The aim of the study was to investigate ex vivo protein binding of BP-C1. Protein binding of BP-C1 was tested using equilibrium dialysis. Pooled blood plasma was used in the study. Control solutions contained the same dosages of BP-C1 in PBS (pH 7.2). Plasma and control solutions were submitted to equilibrium dialysis across a vertical 8 kDa cut-off membrane for 4 h at 37 °C under gentle shaking. Platinum was quantified in dialysis and retained fractions using inductively coupled plasma mass spectrometry after microwave digestion. The dialysis system was tested and validated; this showed no protein saturation with platinum. A medium degree of binding of platinum to macromolecular species of ca. 60% was observed. The study showed the maintenance of a high fraction of free BP-C1 in the bloodstream, facilitating its pharmacological activity.

Analysis of toxic elements in leaves and fruits of loquat by inductively coupled plasma-mass spectrometry (ICP-MS)

This study aimed at analyzing the content of 10 toxic elements (Be, Al, Ti, As, Cd, Sn, Sb, Hg, Pb and Ag) in different tissues (leaf blade, seed, fruit peel and pulp) of loquat fruits, at different maturity stages (immature green, mature green and full ripe) from Fujian (Yun Xiao/Zhangzhou) in China, using inductively coupled plasma-mass spectrometry (ICP-MS), with microwave digestion. Results revealed that the concentrations of Be, Al and Hg in all observed tissues were significantly reduced with the change in maturity of fruits from immature green to full ripe. Whereas the toxicity of Ti, As, Cd, Sb and Pb were observed to be shifted from seed and pulp to peel and leaves. Tin concentration was increased in all observed tissues except seeds, while silver concentration was only increased in fruit peel of loquat. In sum up, toxic elements concentration detected in the fruit pulp of loquat, at full ripe stage, was found safe for human consumption.