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Analytical and Bioanalytical Chemistry Research - Volume:1 Issue: 1, Winter - Spring 2014

Analytical and Bioanalytical Chemistry Research
Volume:1 Issue: 1, Winter - Spring 2014

  • تاریخ انتشار: 1393/06/28
  • تعداد عناوین: 7
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  • Mir Ali Farajzadeh, Leila Khoshmarram, Saheleh Sheykhizadeh Pages 1-19
    Foodstuffs analysis is very important due to population growth and increasing consumer demand for safety and nutritional excellence. The Analysis of different compounds in foodstuffs is so difficult without using sample preparation techniques. Traditional techniques require large amounts of toxic organic solvents. As a result, they are not only expensive but also environmentally unfriendly and they generate a considerable amount of waste. Nowadays efforts are being focused on development of microextraction techniques. Different microextraction techniques such as solid phase microextraction (SPME), stir bar sorptive extraction (SBSE), and liquid phase microextraction (LPME) have found an important place in sample preparation because of their inherent advantages over the conventional procedures. In particular, they have been applied with successfully for the analysis of food samples despite their complexity. The review discusses different microextraction approaches used in analysis of chemical compounds and metal ions in foodstuffs. It summarizes the application of microextraction techniques in food analysis in details as possible.
    Keywords: Food analysis, Sample preparation, microextraction, Chromatography, Spectrometry
  • M. Adibmehr, H. Bagheri Sadeghi, Sh. Dehghan Abkenar Pages 20-28
    A simple and rapid microextraction procedure based on dispersive liquid-liquid microextraction (DLLME) was developed for determination and speciation of trace amounts of chromium (Cr) by flame atomic absorption spectrometry (FAAS). In the proposed approach, chloroform and methanol were used as extraction and dispersive solvents. A new Schiff's base ligand, bis(2-methoxy benzaldehyde) ethylene diimine was used as complexing agent. Effect of extraction solvent, disperser solvent, the volume of extraction and disperser solvent, pH of the aqueous solution and extraction time on extraction procedure were investigated and optimized. Under the optimum conditions, the calibration graph was linear in the range of 1-50 µg l-1 with a limit of detection of 0.7 µg l-1. The relative standard deviation (RSD%) was 2.7% (n = 7) for Cr(III). The relative recoveries of spiked samples were between 98% and 102% and preconcentration factor (PF) was 20. The proposed method is a simple, fast, accurate, highly stable and selective and was applied for determination of chromium in milk and water samples with satisfactory results.
    Keywords: Chromium, Dispersive liquid-liquid microextraction, Flame atomic absorption spectrometry, Speciation
  • Morteza Bahram, Shima Jahangiri, Khalil Farhadi, Reza Hasanzadeh Pages 29-37
    In the present work a pH-dependent cloud point extraction procedure using pH-sensitive hydrogel polymer was applied for preconcentration and spectrophotometric determination of the Hg(II) as its Thio micher's ketone complex. Central composite design (CCD) and response surface method were applied to design the experiments and find out the optimum conditions. Four factors entitled concentration of hydrogel, HCl, TMK and KCl (to study the salting out effect) were investigated. At the optimum conditions, the analytical characteristics of the method (e.g., limit of detection, linear range, Relative standard deviation) were obtained. Linearity was obeyed in the range of 5-200 ng ml-1 of Hg(II) with a correlation coefficient of 0.987. The detection limit of the method was 1 ng ml-1 for Hg(II) ion. Relative standard deviation (RSD) for 7 replicate determinations of complex mercury with Thio micher's ketone was 3.37%. The interference effect of some anions and cations was also investigated.
    Keywords: pH-sensitive hydrogel, Central Composite Design (CCD), Thiomicher's ketone (TMK), Mercury
  • Eva Pocurull, Carolina Martinez, Veronica Gomez, Francesc Borrull Pages 38-49
    A headspace-solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) method has been developed for the simultaneously determination of 20 disinfection by-products (DBPs) in water samples from reverse osmosis (RO) membranes. Selected compounds belong to different families including: trihalomethanes (THMs), halogenated acetonitriles (HANs), halogenated nitromethanes (HNMs), halogenated ketones (HKs) and other halogenated DBPs. Four commercial fibres with different polarities were tested for the extraction of the compounds and the main variables affecting HS-SPME such as extraction time, extraction temperature and pH of the samples were optimized by applying a central composite design. The method showed good detection limits in the range of 0.003 mg l-1 up to 0.010 mg l-1 for most of the compounds with reasonable linearity with r2 higher than 0.991. Moreover, the repeatability of the method, expressed as relative standard deviation (RSD) was lower than 13% (n = 5, 1 mg l-1) in brackish and wastewater samples. The validated method has been applied for the determination of the target DBPs in RO water samples from application research units, which treated water from various origins (wastewater, brackish water and sea water), showing good performance in the different types of studied samples. The analysis revealed the presence of several DBPs regarding different families, such as trichloromethane (with concentrations up to 0.36 μg l-1), chloroiodomethane (0.5-1.44 μg l-1), dibromochloromethane (found at concentrations up to 0.76 μg l-1) and tribromoacetaldehyde (at concentrations up to 11 μg l-1 in the influent samples). The tendency of most of them indicated a trend of removal by reverse osmosis treatments, especially the total concentration of THMs which decreased below the limit of detection.
    Keywords: Advanced membrane water treatment, Disinfection by, products, Gas chromatography-mass spectrometry, Solid-phase microextraction, Trihalomethanes, Water samples
  • M. Ghaedi, M. Montazerozohori, H. Saidi, M. Rajabi Pages 50-61
    Powder activated carbon surface (AC) was modified and altered procedure thorough a facile and easy chemical reaction to appearance of 2- ((3-silylpropylimino)-1-methyl) phenol (AC-(SPIMP)). Subsequently, this novel sorbent efficiently applied for the extraction and preconcentration of some metal ions from real samples. Preliminary the influences of variables such as pH, amounts of reagents and porous AC, eluting solution conditions (type and concentrations), sample volume and influence of interference of many ions on the analytes recoveries was studied and optimized. The proposed sorbent has high surface area ( 1317.1346 m2 g-1) and small pore size (
    Keywords: Chemical modification, Activated Carbon, Solid phase extraction, Pore size distribution, BET analysis
  • Meissam Noroozifar, Mozhgan Khorasani Motlagh, Reza Akbari, Mojtaba Bemanadi Parizi Pages 62-72
    In this study, incorporation of iron ion-doped natrolite nanozeolite, multi-wall carbon nanotubes into chitosan-coated glassy carbon electrode for the simultaneous determination of ascorbic acid, epinephrine, uric acid and tyrosine is studied. The results show that the combination of multi-wall carbon nanotubes and iron ion-doped natrolite zeolite causes a dramatic enhancement in the sensitivity of ascorbic acid, epinephrine, uric acid and tyrosine quantification. The sensor gave the separated and sharp voltammetric responses of analytes in four well-defined linear sweep voltammetry peaks. Under the optimum conditions, the calibration curve were linear up to 1.82 × 10-3, 3.15 × 10-3 , 1.50 × 10-4 and 6.29 × 10-4 M with detection limits 1.82 × 10-6, 1.33× 10-6, 4.09 × 10-8 and 2.01× 10-7 M (S/N= 3) for ascorbic acid, epinephrine, uric acid and tyrosine, respectively. The analytical performance of this sensor has been evaluated for simultaneous detection of four analytes in human serum and urine samples.
    Keywords: Simultaneous determination, Nanozeolite, Multiwalled carbon nanotube, Biocompounds
  • A. Shokrollahi, A. Abbaspourb, A. Naghashian Haghighia, A. H. Kianfar Pages 73-82
    A new Al(III) selective membrane based on 5-bromo(salicylidene-2-amino thiophenol) as a neutral carrier in a poly(vinyl chloride) (PVC) matrix is coated on platinum wire to determine trace amounts of Al(III) ion in various samples. The sensor exhibits a good response for Al(III) ion over a wide concentration range of 5.20 × 10-7 to 1.00 × 10-2 M with Nernstian slope of 19.64 ± 0.15 mV decade-1 and low detection limit of 5.01 × 10-7 M. The performance of the sensor is best in the pH range of 4.00-6.50 without any divergence in potential and it also works well in partially non-aqueous medium. The coated wire electrode has a short response time of about 5 s and is stable for at least 2 months. The proposed membrane electrode revealed good selectivity for Al(III) ion over a wide variety of other metal ions. It was successfully applied for determination of Al(III) ion in different real and environmental samples and also as an indicator electrode for potentiometric titration of Al(III) ion with EDTA.
    Keywords: Al(III) selective electrode, Potentiometric sensors, Coated platinum electrode, Schiff base