Fatih Durmaz

Application of multivariate chemometric techniques for simultaneous determination of five parameters of cottonseed oil by single bounce attenuated total reflectance Fourier transform infrared spectroscopy

Single bounce attenuated total reflectance (SB-ATR) Fourier transform infrared (FTIR) spectroscopy in conjunction with chemometrics was used for accurate determination of free fatty acid (FFA), peroxide value (PV), iodine value (IV), conjugated diene (CD) and conjugated triene (CT) of cottonseed oil (CSO) during potato chips frying. Partial least square (PLS), stepwise multiple linear regression (SMLR), principal component regression (PCR) and simple Beer׳s law (SBL) were applied to develop the calibrations for simultaneous evaluation of five stated parameters of cottonseed oil (CSO) during frying of French frozen potato chips at 170°C. Good regression coefficients (R(2)) were achieved for FFA, PV, IV, CD and CT with value of >0.992 by PLS, SMLR, PCR, and SBL. Root mean square error of prediction (RMSEP) was found to be less than 1.95% for all determinations. Result of the study indicated that SB-ATR FTIR in combination with multivariate chemometrics could be used for accurate and simultaneous determination of different parameters during the frying process without using any toxic organic solvent.

Excess molar volumes, viscosity, refractive index, and Gibbs energy of activation of binary biodiesel + benzene, and biodiesel + toluene mixtures at 298.15 and 303.15 K

Excess molar volumes (VE), viscosities, refractive index, and Gibbs energies were evaluated for binary biodiesel + benzene and toluene mixtures at 298.15 and 303.15 K. The excess molar volumes VE were determined from density, while the excess Gibbs free energy of activation G*E was calculated from viscosity deviation Δη. The excess molar volume (VE), viscosity deviation (Δη), and excess Gibbs energy of activation (G*E) were fitted to the Redlich-Kister polynomial equation to derive binary coefficients and estimate the standard deviations between the experimental data and calculation results. All mixtures showed positive VE values obviously caused by increased physical interactions between biodiesel and the organic solvents.

Oxidation on the Stability of Canola Oil Blended with Stinging Nettle Oil at Frying Temperature

The present study was carried out to investigate changes in fatty acids composition and their ratio by mixing of canola oil (CLO) with cold pressed stinging nettle oil (SNO) during heating at 180°C for 10 h, and analyzed by gas chromatography-mass spectrometry. The blended oils were prepared by gravimetrically mixing of CLO and SNO at various ratios of 60:40 and 40:60 w/w, respectively. Trans fatty acid in fresh CLO and SNO of 1.1 and 0.05%, whereas fresh blended oils of CLO:SNO (40:60, 60:40 w/w) contained 0.44, 0.91% and heated oils of CLO, SNO and CLO: SNO (40:60, 60:40 w/w) were found from 1.35 −2.49, 0.06 −0.09, and 0.46 −0.51, 1.02 −1.27%, correspondingly. The linolenic fatty acid is more prone to oxidation in heated oils and their percentage in fresh CLO, SNO and blended (40:60, 60:40) CLO:SNO samples of 10.58, 0.00, and 3.94, 6.64%, respectively. The linolenic acid was decreased from 10.27 −6.54, 0.00, and 3.93 −3.79%, 6.47 −5.68% in heated CLO, SNO and CLO:SNO (40:60, 60:40 w/w) oils, respectively. The oxidation parameters were also analyzed such as free fatty acids, peroxide value, iodine value, conjugated diene and triene using standard methods. The best results of free fatty acids, peroxide value, iodine value, conjugated diene and triene were obtained in blended CLO:SNO (40:60 w/w) oil at 0.31%, 0.63 meqO2/Kg, 0.79 g/100 g, 60 and 31.36% during 10 h. The obtained results show that mixing of CLO with SNO increased the stability against oxidation and consequently enhanced the worth of CLO during heating/frying route.

Simultaneous determination of some basic dyes using p-tetranitrocalix[4]arene-appended silica-based HPLC column

This study focuses on the synthesis, characterization and application of p-tetranitrocalix[4]arene-appended silica-based material as a stationary phase in high-performance liquid chromatography for the simultaneous separation of some basic dyes such as methyl violet, methyl green and methylene blue. The effect of the pH of mobile phase on the retention, separation and selectivity of these compounds was investigated. The method was validated for system efficiency, linearity, accuracy, precision, limit of detection and quantification. The limits of detection were 0.1, 0.5 and 0.3 mg L−1; whereas, the limits of quantification were observed to be 1, 1.2 and 0.9 mg L−1 for methyl violet, methyl green and methylene blue, respectively. The separation efficiency of the p-tetranitrocalix[4]arene-appended silica-based column was also compared to that of the octadecylsilane column.

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.

Copper sorption efficiency of p-tetranitrocalix[4]arene based high performance liquid chromatographic column

AbstractPresent study deals with the sorption characteristics of p-tetranitrocalix[4]arene (3) appended silica-based high-performance liquid chromatographic (HPLC) column utilized for preconcentration, determination, and purification of Cu2+ from water. The sorption characteristics of the HPLC column were investigated for Cu2+ in column agreement. The experiments were performed in five steps that were monitored using UV–visible diode-array detector. However, all the HPLC experimental results were reconfirmed by using atomic absorption spectrophotometer. The effect of concentration on the sorption efficiency of the column was evaluated for Cu2+ and data obtained was investigated using Langmuir and Freundlich sorption isotherms. The value of coefficient of determination (R2), i.e. 0.99, suggested that the Freundlich sorption isotherm was found to be the best fit model for Cu2+. The developed method was validated for system efficiency, accuracy, and precision, while the data obtained revealed that the develo...

Removal of ciprofloxacin from aqueous solution using wheat bran as adsorbent

ABSTRACT Current study describes sorption of antibiotic drug (ciprofloxacin) by using nontoxic and biocompatible carrier, i.e., wheat bran (WB). For sorption study, various parameters were optimized and Freundlich, Dubinin–Radushkevich, Langmuir, and Temkin isotherm models were applied to demonstrate the mechanism of sorption, while kinetics study for sorption was evaluated using diffusion models, pseudo-first-order kinetic (Langergren) and pseudo-second-order (Ho and McKay) kinetic models. In addition, thermodynamics study was also carried out. However, sorption of ciprofloxacin was pH depended and it showed 75% drug release in alkaline medium (at pH = 1.5) indicating the good release ability of WB for ciprofloxacin.