Semahat Kucukkolbasi

Synthesis and characterization of novel nano-chitosan Schiff base and use of lead (II) sensor

A new kind of nano-chitosan Schiff base ligand (CHNS) with particle size of 34 nm was formed by the reaction between the 2-amino groups of glucosamine residue of nano-chitosan and a 2,5-dihydroxybenzaldehyde. The chemical structures of the nano-chitosan and nano-chitosan Schiff base were characterized by FT-IR spectra, particle sizer, zeta potential, and elemental analysis. A new, simple and effective chemically modified carbon paste electrode with CHNS was prepared and used as a lead (II) sensor. The prepared electrode was characterized using scanning electronic microscopy (SEM-EDX) and cyclic voltammetry (CV). The modified electrode showed only one oxidation peak in the anodic scan at -0.34 V (vs. Ag/AgCl) for the oxidation of lead (II). The dedection limit (LOD) was calculated as 1.36×10(-7) for a 10-min preconcentration time at pH 6.0.

Development of a Spectrofluorimetric Method for Determination of Albendazole in Tablets

Abstract In this study a spectrofluorimetric method was developed to determine drug active compound in the tablets for albendazole (ABZ). For this aim, fluorescence spectra of albendazolee drug active compound in various solvents were taken, it was determined that the most suitable solvent was chloroform and excitation (λex) and emission (λem) wavelength in a row was 360 nm and 440 nm in this solvent. Calibration graphics were drawn and shown linear at 0–2.5 mg/l concentration range (R2=0.9993). Albendazole quantity in the andazol tablets was determined from directly calibration graphs and with standard addition method. Results obtained with developed spectrofluorimetric method were compared with standard USP method and it was found no difference between two methods within 95% confidence limits. It was determined that proposed method was easy and highly accuracy method to be able to use in routine albendazole analyze for the quality control.

DETERMINATION OF DEFENSIN HNP-1 IN HUMAN SALIVA OF PATIENTS WITH ORAL MUCOSAL DISEASES

Saliva is a biological fluid that is easily obtainable and that can give useful information both in systemic and oral diseases. In this study, a chromatographic method was applied to determine the amount of defensin HNP-1 in human saliva of patients with oral mucosal diseases before and after treatments and compared with controls. Defensin human neutrophil peptide-1 (HNP-1) was identified and confirmed. The concentration of HNP-1 in saliva was determined by comparing the area of eluted HNP-1 with that of HNP-1 standard. Linear calibration range of defensin HNP-1 was 0.10 to 0.90 μg/10 μL with R2 values of 0.996. The concentrations of HNP-1 in the saliva of patients with oral lichen planus, Behçets disease, and recurrent apthous stomatitis were 33.6 ± 10.6, 15.5 ± 7.6, and 36.3 ± 9.5 μg mL−1 (mean ± S.D.), respectively. The salivary defensin-1 concentration was significantly higher in patients with oral mucosal diseases than in healthy volunteers; furthermore, in patients with oral mucosal diseases, the concentration was significantly higher before treatment than after treatment.

Electrochemical studies of olmesartan medoxomil and its detection in pharmaceutical dosage forms and biological fluids by cathodic adsorptive stripping voltammetric method

The electrochemical properties of olmesartan (OLME) were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) at hanging mercury drop electrode (HMDE). All studies were based on the irreversible and adsorption-controlled electrochemical reduction signal of OLME at about -1.2 and -1.5 V vs. Ag/AgCl at pH 5.0 in Britton-Robinson (BR) buffer. This adsorptive character of the molecule was used to develop a novel, fully validated, rapid, selective and simple differential pulse cathodic adsorptive stripping voltammeric (DPCAdSV) method for the direct determination of OLME in pharmaceutical dosage form and human urine without time-consuming steps prior to drug assay. Peak current of electrochemical reduction of OLME was found to vary linearly with the concentration in the range from 4.7 × 10-8 mol L-1 (0.0262 µg mL-1) to 8.3 × 10-6 mol L-1 (4.636 µg mL-1). In this method, limit of quantification (LOQ) was found to be 5.1 × 10-7 mol L-1 (0.284 µg mL-1). The method was applied to determine the content of OLME in commercial pharmaceutical preparation and spiked human urine. It was found to be highly accurate and precise, having a relative standard deviation of less than 10% for all applications.

Role of Different Bleaching Earths for Sunfl ower Oil in a Pilot Plant Bleaching System

Abstract The purpose of present study is to investigate the efficiency of different kinds of Turkish commercial bleaching earth materials for changes in different colour pigment concentrations in neutralized sunflower oils. The bleaching experiments were performed in a pilot system under at stable vacuum (50 mmHg) and temperature (100ºC) for 30 min. By examining the changes in chlorophyll, β-carotene and red colour, bleaching process parameters such as type and dosage of the bleaching material were optimised. The sorption characteristics of colour pigments were evaluated using common adsorption isotherms and Scatchard plot analysis. Ads-3 acid-activated earth material at 1% (w/w) per samples was found to be the most appropriate sorbent and the amount of sorbed pigments was calculated as 1.01x10-4 mmol/g ads. for chlorophyll, 1.15x10-3 mmol/g ads. for carotene and 1.70 red on Lovibond colour scale. The procedure indicated that this system can be easily adapted to the actual oil refining systems.

SIMULTANEOUS AND ACCURATE DETERMINATION OF WATER- AND FAT-SOLUBLE VITAMINS IN MULTIVITAMIN TABLETS BY USING AN RP-HPLC METHOD

In the present study, a reversed-phase high-performance liquid chromatographic (RP-HPLC) procedure was developed and validated for the simultaneous determination of seven water-soluble vitamins (thiamine, riboflavin, niacin, cyanocobalamin, ascorbic acid, folic acid, and p-aminobenzoic acid) and four fat-soluble vitamins (retinol acetate, cholecalciferol, α-tocopherol, and phytonadione) in multivitamin tablets. The linearity of the method was excellent (R2 > 0.999) over the concentration range of 10 - 500 ng mL-1. The statistical evaluation of the method was carried out by performing the intra- and inter-day precision. The accuracy of the method was tested by measuring the average recovery; values ranged between 87.4% and 98.5% and were acceptable quantitative results that corresponded with the label claims.

The Use of Voltammetry for Sorption Studies of Pb2+ from Aqueous Media using Schiff Base Immobilized Biologic Polymer Material

Adsorption by low-cost adsorbents and biosorbents is recognized as an effective and economic method for low-concentration heavy metal. The purpose of this study was to investigate the possibility of the utilization of N,N′-bis(2, 5-dihydroxybenzylidene)-1, 4-diaminobenzene (DHDB)-immobilized sporopollenin (Schiff base-immobilized sporopollenin, Sp-DHDB) as a sorbent for removal of lead (II) ion from aqueous solution. The effects of different parameters (such as sorbate concentration, sorbent dosage, and pH of the medium) were investigated by differential pulse anodic stripping voltammetry (DPASV) technique. The experimental data were analyzed by the Freundlich, Langmuir, and Dubinin–Radushkevich (D–R) isotherms. Equilibrium data fitted well with the Freundlich model and the procedure developed was successfully applied for the removal of lead ions in aqueous solutions. This investigation reveals a new, simple, environmentally friendly, and cost-effective method for the removal of lead ions from aqueous solutions by a new Sp-DHDB material.