Classical chemical sciences
Corrosion resistance of three metals namely mild steel, 22 carat gold and 18 carat gold in Ringer Solution –A has been evaluated by polarization study. The corrosion resistance of metals in simulated Ringer Solution-A is follows; 22 carat gold > 18 carat gold > mild steel. This is due to the variation in composition of various types of gold
Keywords: Corrosion resistance of metals, Gold, Mild Steel and Ringer Solution-A (SRSA)
The extraction of Ni2+ from aqueous solutions of various concentrations of SO4 2- ions in buffered media using 1-phenyl-l,3-methyl4- trichloroacetyl-pyrazolone-5 (HTCP) has been investigated. The synergistic effect of butanol on the extraction of the metal was also examined. Ni2+ was quantitatively extracted from solutions by HTCP only at high pH values (5 - 8) over the pH range 0 – 8 studied. However, addition of butanol resulted in a synergistic extraction of Ni2+ up to 97.78% over the range of pH 5.00 – 8.00 from aqueous buffer media containing 0.1M SO4 2- ion concentration. Increased SO4 2- ion concentration resulted in a slight decrease in the extraction of Ni2+ ion due to masking of the metal by the SO4 2- ion. In addition, overall extraction was shifted to higher pH values for extraction into chloroform solution of the ligand for Ni2+ using butanol. The log Kex and pH1/2 of the various extraction systems were determined.
Keywords: Extraction, nickel(II), 1-phenyl-3-methyl-4-trichloroacetyl-pyrazolone-5, effect of pH and sulphate io
The objectives of the review are the collection, concise description and evaluation of the various chromatographic technologies applied for the separation and quantitative determination of macro- and microcomponents present in wines.
Keywords: gas chromatography; high performance liquid chromatography; white wines; red wines, wine specialities
Materials and environmental chemistry
Self-supply with home-produced vegetables is very common in urban areas, where cadmium is a characteristic pollutant due to its anthropogenic origin. It has a harmful effect on human health. People are exposed to cadmium in different ways. One of the most common is through consumption of contaminated food, such as home-produced vegetables. However, different vegetables accumulate cadmium in different concentrations and as such pose different risk to human health. In this research 6 species of vegetables were sampled: endive, chicory, courgettes, tomato, onion and carrot. Vegetables (edible parts) were sampled in gardens of the Municipality of Celje, which is the third largest city in Slovenia. In some areas soils in the city and its vicinity are polluted with heavy metals (e.g. cadmium, lead, zinc) due to past industrial activities. Sampling area was stratified into 6 zones according to Slovenian legislation and the level of soil pollution with cadmium (mg/kg DW): <0.99, 1.00 - 1.99; 2.00 – 3.99; 4 – 7.99; 8 – 11.99; >12. Additionally, vegetables were purchased in local shops, markets and supermarkets in order to compare concentrations of cadmium in vegetables grown in gardens and in purchased vegetables. The main goal of this research was to determine whether purchased vegetables contain significantly lower concentration of cadmium than vegetables produced on gardens of the Municipality of Celje. Results showed that the significant difference between the average concentrations of cadmium in purchased and garden vegetables was observed in vegetables produced in gardens with soil cadmium content above 2 mg/kg DW. Therefore, the recommendation to purchase vegetable rather than to produce it at home garden is justified in areas where the contamination of soil with cadmium is above 2 mg/kg DW when producing carrot, chicory and endive or above 4 mg/kg DW when producing courgettes, tomato and onion.
Keywords: cadmium, contamination, soil, vegetables, garden, market.
SrBi2Nb2O9 (SBN) compound was synthesized by the hydrothermal method at 220°C for 8h. The dielectric characteristics of ferroelectric SBN ceramic in the 10 Hz – 13 MHz frequency range at various temperatures (300-950 K) have been studied. This study relates initially to measurements of dielectric constant (εr'), and the dielectric losses (tanδ) according to the temperature, as well as the determination of the Curie temperature of SBN. The nature of ferroelectric - paraelectric transition was then deduced. The bulk conductivity of SBN ceramic was performed at different temperatures and the activation energy was calculated.
Keywords: Hydrothermal synthesis, Dielectric properties, Ferroelectric transition, Ionic conductivity
A poly (vinyl chloride) matrix membrane sensors for selective determination of camylofin (CY) in pharmaceutical formulations were developed based on the use of dibenzo-18crown-6 (DB18C6) as a neutral carrier and ion-association complex ([CY]2[PM])of (CY) cation with phosphomolybdate anion (PM). Subsequently, these electroactive materials were dispersed in dioctyl sebacate (DOS) as solvent mediator designed and can be easily used in flow injection system. Under static mode of operation, the sensors revealed a near Nernstain response over a wide CY+ concentration range 8.5x 10-6 and 5 x 10-6 to 1.0 x 10-2 mol L-1 with a detection limit of 6.0x10-6 and 2.5x10-6 mol L-1, respectively. In flow injection potentiometry, excellent reproducibility (RSD %±0.7%), fast response, high sensitivity with a near- Nernstian 53.9±1.1 and 40.2±0.8 mV decade-1, linear range 1.0x10-4 -1.0x10-2 mol L-1, detection limit 16.4±0.3 and 5.9±0.3 μg mL-1, high sampling rate (20-22 and 40-45 sample h-1) and stable baseline was observed in the presence of 0.05 mol L-1 citrate buffer, pH 4.5 as a carrier for ([CY]2[PM] and (DB18C6) membrane based sensors, respectively. The utility of the sensors was tested for field monitoring of CY+ in different pharmaceutical formulations collected from the local market.
Keywords: camylofin; smooth muscle relaxant; potentiometric sensor; flow injection analysis
Biochemistry, molecular biology and biotechnology
The essential trace element selenium (Se) exerts complex effects on the endocrine and immune systems, partly due to its antioxidant capacity. The importance of an optimal Se intake has been established in autoimmune thyreoiditis. A recently published study reported beneficial results in Se supplemented patients with mild Graves’ orbitopathy. Eight female patients with mild Graves’ orbitopathy and three female patients with mild orbitopathy based on Hashimoto thyreoiditis participated in the study. The status of the orbita was registered at the beginning of the study and one-six months thereafter both according to the scores recommended by the American Thyroid Association (ATA) and clinical activity scores (CAS). The patients were treated according to their thyroid hormone status, their antibody results and their CAS. Moreover, they received adjuvant 100 or 200 μg Se as sodium-selenite. Serum Se concentrations were measured before Se supplementation was implemented and 1-6 months after the beginning of treatment.. ATA scores improved in 10 patients and worsened slightly in one female patient. CAS improved in all study participants. Mean Se concentrations were 75.08±11.55 μg L-1 before supplementation was started and 91.35±17.37 μg L-1 one-eight months later (p<0.05). At the beginning of the study, the majority of patients exhibited elevated antibody levels. After conventional treatment and adjuvant Se supplementation, antibody levels decreased or reached the normal range (except in the case of one patient).
Keywords: selenium, Graves’ orbitopathy, clinical activity scores
Fresh asparagus is rich in protein, vitamins and minerals with high nutritional value. But nutritional content and composition are affected by the genotype and the harvest time. In our trials at the experimental farm Pallag of Debrecen University 3 asparagus varieties (Cumulus, Gijnlim, Grolim) were tested on brown humus sand soil in ridge cultivation. Solids, nutritional fibre, protein, sugar and vitamin-C contents were measured in the white spears at 3 different harvest times (8 May, 24 May, 6 June 2012). Mineral element tests included B, Ca, Cu, Fe, K, Mg, Na, P, S, Zn and sulphate sulphur. Our trials confirmed the strong negative correlation (r = -0.828) between the sugar and vitamin-C content of the spears. This investigation confirm that the variety with higher vitamin-C content has lower flavour materials. On the start of the harvest period we measured higher sugar and lower vitamin-C content in the spears. In our variety comparison trial the variety Cumulus had the highest solids (7.1 %), nutritional fibre (4.7 %), protein (2.81 %) and sugar (3.51 %) contents on the brown humus sand. Among the microelements the high Fe content (4.93 – 7.63 mg kg-1 fresh weight) deserves attention. Fe is variety dependent at different genotypes. The highest value was found in Gijnlim with 7.63 mg kg-1 on fresh weight basis. The sulphate-S content is responsible for the special taste and flavour of asparagus. In our trials Cumulus had the highest sulphate-S value (279 mg kg-1 fresh weight). Cumulus also excelled in Mg content (84.10 mg kg-1 fresh weight) and Grolim in Ca content (27,23 mg kg-1 fresh weight). The low Na content of the element composition is essentially favourable. It varied between 17.07 and 27.23 mg kg-1 on fresh weight basis in the tested 3 varieties.
Keywords: asparagus, mineral elements, vitamin-C, Sulphate-S, different harvest times
Industrial and engineering chemistry
A few of synthetic methods of isoamyl benzoate using different catalysts such as sulfonic acid (p-toluene-sulfonic acid and aryl sulphonic acid), inorganic salt (NH4Fe(SO4)2·12H2O, NaHSO4·H2O, Fe2(SO4)3 ·xH2O and FeCl3·6H2O), heteropolyacid (H4O40W12 and TiSiW12O40/TiO2) and solid super acid (Ti(SO4)2/TiO2 and Zr(SO4)2·4H2O) have been discussed in the present paper. The yields of isoamyl benzoate have been improved by the addition of above catalysts. Due to simple process and low investment cost these methods are having an advantage over other conventional methods.
Keywords: overview; synthetic study; isoamyl benzoate; catalysts
Three synthetic methods of alkyl cinnamates using different catalysts such as heteropolyacids (H8SiW12O42·XH2O) and solid superacids (SO4 2-/La2O3-ZrO2-HZSM-5 and SO4 2-/TiO2) have been reviewed in the present paper. Effects of the reaction conditions such as the microwave heating power and times, the amount of the catalyst, the molar ratio of cinnamic acid to alcohols and the reaction time on the yields of alkyl cinnamates have also been discussed. The yields of alkyl cinnamates are improved by the addition of the abovementioned catalysts. Due to low investment costs and simple process these methods are having the advantages on other processes.
Keywords: overview; synthetic method; alkyl cinnamates; catalysts