Mixture Of HClO4 Research Articles

ZAWARTOŚĆ SELENU W GONADACH SAMCÓW I SAMIC DZIKA EUROAZJATYCKIEGO (SUS SCROFA) Z WOJEWÓDZTWA MAZOWIECKIEGO

Selenium is counted among the trace elements necessary to maintain metabolic processes occurring in the animal body, including reproductive processes. The aim of the study was to assess selenium content in testes and ovaries of wild boars (Sus scrofa) in an attempt to establish a range of reference values for individuals of this species. Selenium concentrations in tissues tested were determined using spectrofluorometric method after wet mineralization in HNO3 and HClO4 mixture. Based on the results, it was found that male wild boars accumulated significantly higher concentrations of Se than females. The average content of this element in the testes of wild boars was 0.32 mg · kg−1 while in the ovaries it was at the level of 0.14 mg · kg−1 wet weight. In addition, the gonads of males were characterized by a higher variability of the analyzed parameter in relation to samples obtained from female wild boars. The coefficient of variation in their case was almost 40.9, while the value of the coefficient of variation for selenium content in the parenchymal layer of the ovaries was 24.9. On the basis of statistical analysis, highly significant differences were found at p ≤ 0.01 according to the sex of the individuals studied. Despite the fact that samples were taken from individuals living in areas with selenium deficiencies due to the biogeochemical background, it should be considered that the supply of Se is optimal, which is evident in the population growth dynamics of individuals of this species in the study area.

ZAWARTOŚĆ SELENU W JAJNIKACH WOLNO ŻYJĄCYCH CERVIDAE Z TERENU PÓŁNOCNO-WSCHODNIEJ POLSKI

Selenium is counted among the trace elements necessary for the maintenance of metabolic processes occurring in the animal body, including the proper functioning of the reproductive system. The aim of the study conducted was to analyze the selenium content in the ovaries of red deer (Cervus elaphus) and European roe deer (Capreolus capreolus) in an attempt to establish a range of reference values for individuals of these species. Selenium concentrations in tissues tested were determined using spectrofluorometric method after wet mineralization in HNO3 and HClO4 mixture. Ovaries Se concentrations ranged from 0.034–0.338 mg⋅kg−1 wet weight and 0.015–0.285 mg⋅kg−1 wet weight in roe deer and red deer respectively. Based on the results, it was found that the average selenium content was higher in the ovaries of red deer and was 0.11 while in roe deer it was 0.09 mg⋅kg−1 wet weight. The gonads of European roe deer were characterized by higher variability of the analyzed pa- rameter in relation to samples obtained from female red deer. The coefficient of variation in their case was almost 90.1, while the value of the coefficient of variation for selenium content in the parenchymal layer of ovaries in red deer was almost 67.6.

Efficient benchtop acid digestion of organic-rich sediments for ICP-MS analyses: testing analytical procedures on NIST 2702 standard reference material

Trace element abundances in organic-rich sediments are widely used in various fields of the geosciences, yet few contributions discuss the effectiveness of low-cost benchtop acid digestion techniques for such samples. Here, we tested three different sample preparation methods (acid digestion in closed and open vessels, and fusion) on twelve powder aliquots of organic-rich sediment, standard reference material NIST 2702. Comparison of newly obtained ICP-MS and LA-ICP-MS results with their respective certificate values, facilitates the assessment of digestion efficiency and the effects of vessel size, acid mixture, and other parameters on the recoveries of 29 trace elements. Our results show that benchtop digestion of organic-rich sediment in closed 7 mL PFA vessels using HF+HNO3+HClO4 mixture is more efficient compared with open vessel digestion treated with the same acid mixture (± HCl), with closed or open vessel digestions without HClO4, and with LA-ICP-MS measurements on fused glass discs.

Highly Efficient β‐Functionalized Oxidomolybdenum(V) Corroles for Catalytic Oxidative Bromination of Phenols at Room Temperature

AbstractTwo new β‐functionalized oxidomolybdenum(V) corroles, oxido[3‐formyl‐5,10,15‐triphenylcorrolato]molybdenum(V) (Mo‐1) and oxido[3‐dicyanovinyl‐5,10,15‐triphenylcorrolato]molybdenum(V) (Mo‐2) were synthesized and characterized by various spectroscopic techniques and electrochemical studies. Mo‐2 manifests splitted B bands due to x and y polarizations and highly red shifted longest B and Q bands due to the electron‐deficient nature of the dicyanovinyl group. EPR data showed that these complexes exhibit an axial compression with dxy1 configuration. DFT studies revealed that HOMO and LUMO orbitals are stabilized in Mo‐2 relative to Mo‐1. Mo‐1 exhibits two successive reversible reductions and two oxidation potentials in cyclic voltammetry. Surprisingly, Mo‐2 exhibits three successive reversible reductions and two oxidations; the one extra reduction could possibly be due to the reduction of the dicyanovinyl moiety. The catalytic activities of Mo‐1 and Mo‐2 for the oxidative bromination of various phenols using H2O2‐KBr‐HClO4 mixture in water have been explored and exhibited excellent activity at a very low catalyst loading of 0.0030 and 0.0028 mol%, respectively. Both synthesized β‐functionalized Mo(V) corroles manifest much higher conversion and TOF (59801–71174 h−1) for oxidative bromination of phenols relative to earlier reported meso‐functionalized Mo(V) corroles (20781–61646 h−1). Hence, Mo‐1 and Mo‐2 mimic vanadium bromoperoxidase (VBPO) and act as functional models for these catalytic applications. These catalysts were reused upto 3 cycles and showed conversion rate upto 82 % indicating their excellent thermal and chemical stabilities.

Evaluation of metal contents of selected red wines consumed in South-East Nigeria

ABSTRACT Some metals (aluminium, lead, zinc and cadmium) contents and their potential health risks in 36 different brands of red wines locally produced and imported to South-East Nigeria are reported. The metals were determined using flame atomic absorption spectrometry after digestion with HNO3 and HClO4 mixture. The results revealed their mean concentration ranges as: Al (0.14 ± 0.01–16.02 ± 0.04 mg/L); Cd (not detected (ND) to 0.012 ± 0.02 mg/L); Pb (nd to 0.65 ± 0.01 mg/L) and Zn (0.08 ± 0.10–12.10 ± 0.12 mg/L). The concentration values obtained for the metals in some of the wines studied were higher than the maximum allowable limits established by Office International de la Vigne et du Vin. The brands of wines (made in Nigeria and imported ones) popularly consumed in the region are contaminated by these metals especially Zn and Cd. This is a source of concern due to possible health risks associated with their ingestion.

Evaluation of antioxidant activities and essential/toxicmetal levels and their health risk assessment in citrus fruits from Pakistan.

Fruits are important components of human diet, and their contamination by environmental pollutants is an emerging challenge nowadays. The present study is based on the measurement of selected essential and toxic trace metals including Na, K, Ca, Mg, Fe, Zn, Cu, Mn, Cr, Co, Sr, Li, Ni, Pb, and Cd in commercially available citrus fruits from Pakistan. The samples were digested in HNO3 and HCLO4 mixture, and the metal contents were quantified by flame atomic absorption spectrometry. Highest concentration was found for Ca (609.0-3596 mg/kg), followed by relatively higher levels of K (277.6-682.1 mg/kg), Mg (53.65-123.4 mg/kg), Na (1.173-52.14 mg/kg), and Fe (0.236-10.57 mg/kg), while Li, Ni, and Cd showed the lowest contributions in most of the samples. In addition, antioxidant activities such as DPPH radical scavenging assay, hydroxyl radical scavenging activity, ferrous chelating activity, ferric reducing antioxidant power assay, and phosphomolybdenum assay were also evaluated in the fruit samples. Considerably higher antioxidant activities were shown by grapefruit, mandarin, sweet lime, and tangerine. Most of the antioxidant assays were significantly correlated with Na, Mg, Fe, Mn, and Cu levels in the fruits. Human health risk was evaluated in terms of health risk index (HRI), target hazard quotient (THQ), and target cancer risk (TCR) which revealed insignificant health risks; thus, the consumption of these fruits can be considered as safe for human diet.

Through-hole AAO-SA templates with a small pore diameter prepared by the voltage pulse detachment method

A voltage pulse detachment method is a fast and simple alternative for the preparation of nanoporous anodic aluminum oxide (AAO) templates. Free-standing through-hole porous anodic aluminum oxide membranes were fabricated by a two-step self-organized anodization of aluminum in a sulfuric acid (SA) solution followed by a voltage pulse detachment process in a mixture of HClO4 and C2H5OH (1:1 vol). In this work, the influence of height, time and number of the voltage pulses, time and conditions of sample storage, and the thickness of oxide layer on the measured current density, bottom-side morphology of the AAO-SA membrane, pore diameter, and overall detachment effect were examined in detail for the first time. The pore diameter of the AAO-SA membranes was estimated from FE-SEM images. It was found that the maximum current density, measured during the voltage detachment process, is the most strongly affected by the conditions and time of sample storage and the AAO thickness. The number of applied pulses and pulse duration influence the most significantly the pore diameter at the bottom side. The as detached AAO membranes with the pore diameter of ca. 20 nm were used as templates for electrodeposition of Au nanowire arrays.

Development of a simple and rapid microwave-assisted extraction method using very dilute solutions of perchloric acid and hydrogen peroxide for the multi-elemental analysis of food materials by ICP-OES: A green analytical method

A simple and rapid microwave-assisted extraction (MAE) method for the quantitative determination of various elements by inductively coupled plasma optical emission spectrometry (ICP-OES) has been developed. A single-step MAE procedure employing very dilute solutions of a mixture of HClO4 and H2O2 was utilized for the extraction of Zn, P, Cd, Pb, Fe, Mn, Mg, Cu, Ca, Al, Na and K from wide range of food materials (wheat flour, brown bread, total diet and skimmed milk powder). Critical parameters affecting MAE process such as extractant concentration (HClO4 and H2O2), extraction time and temperature were optimized to get quantitative recovery of elements. The methodology was optimized by using two representative food based reference materials; wheat flour NIST-1567a and non-fat milk powder NIST-1549. The solid residues remained after MAE extraction was filtered and the supernatant was diluted 3–10 times with high purity water before analysis by ICP-OES. These studies indicate that the method is a rapid (within 15 min) and quantitative recoveries (>95%) for all the selected elements, were obtained using a 2% (v/v) HClO4 and 4% (v/v) H2O2 mixture as extractant. The optimum microwave extraction parameters obtained were: temperature - 140 °C, pressure - 6 bar and time - 10 min. The accuracy of the proposed MAE method was further evaluated analyzing two more certified reference materials, brown bread BCR-191 and total diet NIST-1548. It was possible to perform the extraction of up to 0.5 g of food materials using an optimized extractant mixture of 2% (v/v) HClO4 and 4% (v/v) H2O2 with resultant carbon content lower than 3470 mg L−1. The results showed no significant statistical difference (Student's t-test, 95% confidence level) between found values and certified values. The recoveries ranging from 97 to 104% were obtained with RSD values <8%. Under optimal conditions, the limits of detection (LOD) of selected elements ranged from 0.01 mg kg−1 to 7.8 mg kg−1 were obtained for ICP-OES in conjunction with present MAE method. The optimized MAE approach was subsequently applied to wheat flour samples of a few leading brands purchased from local super market. These investigations reveal that the proposed MAE method in conjunction with ICP-OES can be utilized for the quantitative determination of various elements in wide range of food materials on regular basis.

Effect of Chemotherapy on Zn, Fe, Mg, Pb, Ca and Se in the Serum

Trace element concentrations in blood serum are very important in various carcinomas. However, the literature lacks in studies of the relationship between the trace element concentrations and cancer types. The present study analyzes blood serums from 40 patients with throat, stomach and lung cancers by inductively coupled plasma optical emission spectrometry (ICP-OES) after low-volume microwave digestion. 7 elements were investigated: Se, Ca, Fe, K, Mg, Pb, and Zn. The elements were categorized into macro elements (Ca, Mg, K) and trace elements (Fe, Zn, Pb, Se) for human blood. The mixture of HClO4:HNO3:H2SO4 was selected for analyzing the trace elements in serums taken from cancer patients. The digested blood serums of pre-chemotherapy and post-chemotherapy were analyzed to investigate the effect of chemotherapy on amounts of trace elements. Decreases were observed in amounts of the essential trace elements except Pb for post-chemotherapy by time, as biochemical reactions were catalyzed by many enzymes and proteins. Certain changes must be made in the scientific approach in cancer therapy. Such changes in treatment of the patient with cancer should include continuous treatment of each patient individually according to the results obtained.

Relationship between soil properties, p sorption characteristics and fertilizer p for optimum yield of soybean (Glycine Max (L.) Merr.) on some inceptisols in Benue

Phosphorus (P) sorption influences P requirement of Nigerian soils. Four Inceptisols in Benue state were therefore used to examine the influence of soil properties on sorption indices and yield of soybean. Soil inorganic P was fractionated using standard procedures. Sorption characteristics were determined in 0.01 M CaCl2 solutions of various P concentrations. For each soil, the amounts of P that gave 0.025, 0.05, 0.075, 0.100, 0.125, 0.150, 0.175, 0.200, 0.225, 0.250 mg/kg solution concentration and the buffering capacity were estimated from adsorption curves. In the greenhouse, 4 kg of soil from each location was placed in plastic pots. Amount of P estimated from sorption study was added as KH2PO4. The treatments were laid out in Randomized Complete Block Design (RCBD) and soybean seed variety (TGx 1448-2E) was planted and observed to maturity. At harvest, the shoot was dried, weighed, milled and digested in a 4:1 HNO3:HClO4 mixture and analyzed for P. Optimum solution P concentration (SPC) was determined for each soil in relation to yield. The P adsorption capacities (K) of the soils related significantly to P in biomass (r=0.661). High grain yield (t/ha) was obtained at 0.025 mg P/kg SPC in Abeda-Mbadyul (8.5) and Otobi-Akpa (12.5) while 5.4 t/ha was obtained in Tor-donga and 4.1 t/hain Odobaat 0.10 mg P/kg SPC in the green house experiment. Slightly higher grain yield was obtained at Otobi (6.4t/ha) in the field trial than the estimated SPC values. Buffering capacities of soils varied and related significantly with seed weight (r= 0.605) and P in biomass (r=-0.667). Consequently, Odoba would require highest P fertilizer application (604.84 Kg P/ha), Tor-Donga (112.31), Abeda-Mbadyul (105.93) and Otobi (33.18)

Wild boars (Sus scrofa) as bioindicators of environmental levels of selenium in Poland

The objective of the study was to determine selenium content in selected organs (liver, kidney) of wild boars from different regions of Poland. Materials for the study were obtained from 28 sites located in 16 provinces of Poland. Selenium concentrations in organs were determined using spectrofluorometric methods after wet mineralization in HNO3 and HClO4 mixture. Mean selenium concentrations in the investigated wild boars from Poland were 0.230 μg/g wet weight in the liver and 1.327 μg/g w.w. in the kidneys. Hepatic and nephric Se concentrations ranged from 0.036-0.626 μg/g w.w. and 0.322-4.286 μg/g w.w., respectively. Selenium concentrations in the wild boars differed considerably according to geographical location. Concentrations of selenium were highest in wild boars from south-eastern provinces and lowest in animals from northern provinces. Most of Poland's area is environmentally deficient in this trace element, as evidenced by marginal selenium levels in the organs of the wild boars.

A Comparative Study of Anodic Aluminum Oxide Preparation for Synthesis of Nanomaterials

A template-based synthesis of nanomaterials is one of the most simple and low-cost fabricating way. The template-assisted method, which employs porous anodic aluminum oxide (AAO) templates, allows for a precise control of the morphology and dimensions of deposited nanowires [1, 2]. Nanoporous Al2O3 can be prepared by a two-step anodization of aluminum in acidic electrolytes. During the anodization, Al foil [2] or Al film sputtered on conducting substrates [3] is subjected to anodic oxidation. The anodization of Al foil results in the Al2O3/Al substrate, which is not suitable to carry out a direct electrodeposition into the pores, due to the presence of the non-conductive oxide barrier layer at the oxide/metal interface. To enable a direct electrodeposition in the Al2O3/Al substrate, the barrier layer at the pore bottom has to be removed. There are two basic methods used for the removal of the barrier layer: wet chemical etching [1, 2] and electrochemical [4–8]. The first one, the wet chemical etching requires additional steps, which include: dissolving the aluminum layer remaining after anodization of the Al foil, pore opening and widening in a phosphoric acid solution to obtain a through-hole membrane, and the sputter deposition of the conductive metal layer that serves as a working electrode during electrodeposition. Drawbacks of this method are: the use of harmful chemicals (HgCl2, CuCl2) [2] or concentrated acid solutions (H3PO4, HCl) [1, 2], and multi-stage process (loss of the material at each stage). The alternative method is based on the electrochemical reduction of the barrier layer. Due to the fact that the thickness of the barrier layer depends on the anodizing potential, a gradual decrease in the applied potential leads to a significant reduction of the barrier layer thickness. As a result of this treatment we obtain AAO, with dendritic channels with a very thin barrier layer at the pore bottoms. Such a structure allows to conduct the direct electrodeposition on the aluminum substrate without any additional steps. An important advantage of this method is the fact that the potential reduction is carried out in the same electrolyte in which the anodization was realized. Therefore, the potential reduction can be performed immediately after the anodizing process. On the other hand, there is a new electrochemical method developed by Lira and Paterson [7] for AAO detachment from the aluminum substrate. It was found that a large voltage pulse applied to the sample results in simultaneous membrane detachment and pore opening. The voltage detachment method has significant advantages over the typically used chemical etching, e.g., it is faster, and environmental friendly. As-obtained AAO membranes are suitable for electrodeposition of metallic nanostructures. Herein, we report on investigation of electrochemical methods for the AAO membrane preparation and their optimization toward further metallic nanostructure deposition. Highly ordered nanoporous AAO templates were fabricated by a two-step self-organized anodization of aluminum carried out in oxalic and sulfuric acids solutions. In the first method, the barrier layer thinning was done by applying an exponentially decreasing voltage at the end of anodization process. Depending on the function used for the reduction of the barrier layer and its thickness, the dendrite-like structures of the barrier layer were observed at the cross-sections. In the second method, a modified voltage detachment method in a mixture of HClO4 and ethanol was used. Different pulses were applied for the detachment of alumina formed in oxalic and sulfuric acids.

Growth Behavior of Anodic Alumina Nanofibers Fabricated By Pyrophosphoric Acid Anodizing and Their Hydrophilicity

Introduction Anodizing of aluminum is a simple electrochemical technique that has been widely investigated in the fields of surface science and engineering for corrosion protection, electronic devices, and optical materials. Anodic oxide films fabricated via anodizing can be typically classified into the following two groups: barrier type oxide films formed in neutral solutions and porous type oxide films (porous alumina) formed in acidic and alkaline solutions. Here, we have demonstrated the fabrication of novel anodic alumina nanofibers via a simple anodizing technique in a new electrolyte, pyrophosphoric acid (H4P2O7). Experimental High-purity aluminum specimens (99.99 wt%, 110–400 µm thick) were ultrasonically degreased in ethanol for 10 min. After drying, the specimens were electropolished in a 13.6 M CH3COOH/2.56 M HClO4 mixture (T = 280 K) at a constant voltage of 28 V for 1 min. The electropolished specimens were immersed in a concentrated pyrophosphoric acid solution (74.0-78.0 wt%, T = 293 K), and then were anodized at a constant voltage of 10 to 95 V using a PC-connected direct-current power supply. A platinum plate was used as the cathode for pyrophosphoric acid anodizing. The surface nanomorphology of the anodized specimens was examined by field emission scanning electron microscopy (FE-SEM) and scanning transmission electron microscopy (STEM). The water contact angles on the aluminum surface anodized via each anodizing condition were measured by an optical contact angle meter. For the wettability measurements, the volume of distilled water placed on the surface of the specimens was adjusted to a relatively large amount of 4 µL to evaluate the superhydrophilic behavior in the initial stage of the measurements. Results and discussion Figure 1 shows the SEM images of the aluminum specimen anodized in pyrophosphoric acid at 50 V and 293 K for 12 min. The thin barrier anodic oxide, which was several tens of nanometers in thickness, was observed on the aluminum substrate by SEM observation of the fracture cross-section (Fig. 1a). This thin barrier oxide was immediately formed on the aluminum substrate by applying a constant voltage for 30 s. Due to additional anodizing for 4 min, a honeycomb oxide structure with narrow hexagonal walls was formed on the aluminum surface (Fig. 1b). Although the nanomorphology of the oxide is very similar to the structure of anodic porous alumina, the nanopores in the honeycomb layer are considerably larger than those obtained by typical anodizing in other acidic solutions. Therefore, vigorous chemical dissolution of the anodic oxide occurs during anodizing. When the anodizing time increased to 12 min, fibrous nanostructures were formed on the honeycomb layer, and several nanofibers became tangled and bundled together due to bending under their own weight (Fig. 1c). The bottom honeycomb alumina contains phosphorus that is due to the incorporation of anions originating from the electrolyte, which is similar to typical porous alumina. However, phosphorus is not found in the alumina nanofibers. The anodic oxides without anions remain during long-term pyrophosphoric acid anodizing because of their slow dissolution rate, and numerous anodic alumina nanofibers cover the aluminum surface during anodizing. The water contact angle on the nanofiber-covered aluminum surface decreased with time after a 4-µL droplet was placed on the surface, and a superhydrophilic behavior with a contact angle measuring 2.2° was observed within 2 s; this contact angle is considerably lower than those observed for electropolished and porous alumina-covered aluminum surfaces. Figure 1

Preparation of Sulfur-Free Exfoliated Graphite in the Graphite-HClO&lt;sub&gt;4&lt;/sub&gt;-CH&lt;sub&gt;3&lt;/sub&gt;COOH Systerms

The sulfur-free exfoliated graphite(EG) was prepared by chemical oxidation method using the mixture of HClO4 and CH3COOH as reaction medium, the 100 orders natural flake graphite(NG) as raw material, and KMnO4 as oxidant. The effects of influence factors on the exfoliation volume(EV) were analyzed by single factor experiments and orthogonal experiments, the structure of NG and EG were characterized by X-ray diffraction. Results show that the optimum preparation conditions were as follows: graphite(g): KMnO4(g): the mixed acid (mL) = 1:0.35:4, HClO4 (mL):CH3COOH (mL) = 3:1, reaction temperature at 35°C for 90 minutes, the maximum EV of up to 500mL/g. The influence factors are governed the descending order: the volume ratio of HClO4 :CH3COOH, reaction temperature, the dosage of mixed acid, the dosage of KMnO4, reaction time.

The profile distribution of zinc in arable alluvial soils with naturally elevated content of calcium carbonate

The objective of the study was to analyze profile spatiation of total and DTPA-extractable zinc forms in alluvial arable soils. Six soil profiles located in the Unislaw Basin were analyzed. The soils were classified as alluvial black earths. The alluvial material of the examined soils was overlying calcareous sinter situated 100 cm deep into the ground. Soil samples were analyzed for the grain size composition, reaction, Corg and the CaCO3 content. The total zinc concentration was assessed after mineralization in HF+ HClO4 mixture according to Crock and Severson (1980), while zinc forms extractable with DTPA were assayed with ASA as described by Lindsay and norveLL (1978). The soils did not show symptoms of zinc pollution. Its total, Zn concentrations ranged between 6.25 and 18.78 mg kg–1, while an average content was 11.16 mg kg–1. The analyzed soil samples contained zinc forms extractable with DTPA in amounts fluctuating between 0.32 and 2.6 mg kg–1. The highest concentrations of total and available zinc were noted in the surface horizons of the soils and in the horizons enriched with organic carbon.

Estimating the Phosphate Fertilizer Need of Soybean (Glycine Max (L) Merr.) In Some Ultisols In Benue State, Nigeria From Their Solution Phosphate Concentration

Ultisols in Benue state were studied to determine the solution phosphate concentration (SPC) required to obtain optimum yield of soybean for estimating the P fertilizer requirement of soybean. Soil inorganic P was fractionated using standard procedures. Sorption characteristics were determined in 0.01 M CaCl2 solutions of various P concentrations. Amounts of P that gave 0.025, 0.05, 0.075, 0.100, 0.125, 0.150, 0.175, 0.200, 0.225, 0.250 mg kg -1 solution concentration were estimated from adsorption curves. In the greenhouse, 4 kg of soil from each location was placed in plastic pots. P estimated was added as KH2PO4. Treatments were laid out in Randomized Complete Block Design. Soybean (TGx 1448-2E) was planted to maturity. The shoot was dried, weighed, milled and digested in a 4:1 HNO3:HClO4 mixture and analyzed for P. SPC was determined in relation to yield. Field trial was conducted at Vanam and phosphate fertilizer quantity that resulted in 0.0, 0.5 SPC, 1.0 SPC, and 2.0 SPC was added per plot, seeds were drilled and replicated thrice. At harvest, SPC that gave highest grain yield was evaluated and the quantity of P required (SPR) to achieve this concentration was calculated. High grain yield was obtained at Vanam and Abaji-Kpav at SPC of 0.025 mg P kg -1 , Ogyoma attained optimum yield at 0.050 mg P kg -1 and Ofugo of 0.075mg P kg -1 , in the green house experiment. The estimated SPC value gave high grain yield in the field trial. Highest P fertilization would be required at Ofugo while Vanam would require the least.

Cadmium in locally grown rice (Oryza sativa) in Nigeria

Cadmium levels were determined in locally grown rice samples in Nigeria and any potential risk involved in their consumption was assessed. The dried samples were digested with a 1:1 HNO3:HClO4 mixture and analysed with atomic absorption spectrophotometer (AAS). Mean cadmium values (mg/kg) were: Adamawa (0.50 ± 0.02), Benue (0.63 ± 0.05), Nasarawa (0.48 ± 0.10), Taraba (0.48 ± 0.10), Anambra (0.49 ± 0.09), Ebonyi (0.60 ± 0.08) and Enugu (0.59 ± 0.10). All samples exceeded the Codex Alimentarius maximum limit for cadmium in rice. The dietary intake for a 60 kg adult ranges from 235 to 309 µg/week in the northern region and 240–294 µg/week in the south-eastern region. The target hazard quotient (THQ) ranged from 0.54 to 0.71, which is less than 1, indicating that the population will not be exposed to a potential health risk from dietary cadmium. However, the measured cadmium levels in rice should be of concern.

Development of radio analytical method for in-vitro monitoring of Pu in urine matrix

ABSTRACT A relatively less expensive and less time consuming radioanalytical technique for quantitative determination of Pu in urine at the mBq level was developed. In this new method, Pu in urine is co-precipitated with Ca2C2O4 from wet oxidized urine matrix and oxalate ions is destroyed with HClO4· Pu in +4 state is extracted into 0.01M PC-88A (2-ethyl hexyl phosphonic acid mono-2-ethylhexyl ester)dissolved in toluene from optimized 2M HCl aqueous phase. Pu is stripped into 5% oxalic acid solution and is evaporated with HNO3–HClO4 mixture to destroy oxalate ions. Finally, Pu is electro deposited in ammonium oxalate medium and counted in an alpha spectrometer. The detailed study of the work is presented in this paper. An interference study on elements that are normally present in urine and other actinides (if present) was performed and is also given.

Effects of Ionic Strength and Charge Density on the Stability of Chloride Complexes of Trivalent Lanthanides

The stability constants of chloride complexes of trivalent praseodymium, europium, erbium, and lutetium (βLn,ClI and βLn,2ClI) were determined at 303 K in a mixture of HClO4 and HCl media (ionic strength between (1 and 4) mol·dm−3) by means of a solvent extraction method using dinonyl napthalene sulfonic acid. Praseodymium and erbium concentrations were measured by a VIS spectrophotometric method using xylenol orange at pH 6, whereas radioactivity measurements were undertaken for europium and lutetium. The specific ion interaction theory (SIT) was applied for the calculation of log10 βLn,Cl0, and a general view of the behavior of the first chloride constants against charge density of lanthanides was obtained.

Atomic-absorption spectrometric determination of catalytic components (Pd, Ti, and Cu) in mixtures based on phenol

Procedures for the determination of palladium, titanium, and copper in organic reaction mixtures based on phenol were developed with the use of atomic absorption spectrometry and various sample preparation techniques: quantitative back extraction of the metals with a 2 M HCl solution; autoclave digestion in an acid mixture of HClO4, HF, and HNO3; and decomposition in a muffle furnace. The accuracy of analysis was demonstrated by a comparison between the results of the atomic-absorption spectrometric determination of the elements obtained with the use of all of the sample preparation techniques proposed and the standard addition method. The relative standard deviation in the determination of palladium, copper, and titanium was 7–10%.