http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2013 , Hindawi Publishing Corporation . All rights reserved. Tue, 18 Jun 2013 09:33:07 +0000 http://www.hindawi.com/journals/ijac/2013/305124/ UV-visible and atomic spectrophotometry and HPLC techniques were applied for the determination of tetracycline (TC) in pharmaceutical preparations via complexation of the drug with Au(III) and Hg(II) ions in solutions. The mole ratio of TC to metal ions was 1 : 1. Maximum peak absorption at λ 425 and 320 nm for the two ions, respectively, was optimized at heating temperature 75°C for 15 minutes at pH = 4 followed by the extraction with ethyl acetate. The percentage of extraction and stability constants for the two complexes was 95.247, 95.335% and ,  M−1, respectively. HPLC method was applied without extraction process. The analytical data obtained from direct calibration curves of UV-visible absorption, FAAS, and HPLC for Au(III) complexes were recovery (100.78, 104.85, and 101.777%, resp.); detection limits (0.7403, 0.0997, and 2.647 μg/ml, resp.); linearity (5–70, 5–30, and 10–150 μg/ml, resp.), and correlation coefficient (0.9991, 0.9967, and 0.9986, resp.). The analytical data obtained from direct calibration curves for Hg(II) complexes by UV-visible spectrophotometry and HPLC were recovery (100.95 and 102.000%, resp.); detection limits (0.5867 and 2.532 μg/ml, resp.); linearity (5–70 and 10–150 μg/ml, resp.); and correlation coefficients (0.9989 and 0.9997, resp.). Ahlam Jameel Abdulghani, Hadi Hassan Jasim, and Abbas Shebeeb Hassan Copyright © 2013 Ahlam Jameel Abdulghani et al. All rights reserved. Tue, 28 May 2013 17:45:08 +0000 http://www.hindawi.com/journals/ijac/2013/501856/ The discovery of high concentration uranium deposit at Mkuju, southern part of Tanzania, has brought concern about the levels of natural radioactivity at villages in the neighborhood of the deposit. This study determined the radioactivity levels of 30 soil samples and 20 water samples from Likuyu village which is 54 km east of the uranium deposit. The concentrations of the natural radionuclides 238U, 232Th, and 40K were determined using low level gamma spectrometry of the Tanzania Atomic Energy Commission (TAEC) Laboratory in Arusha. The average radioactivity concentrations obtained in soil samples for 238U (51.7 Bq/kg), 232Th (36.4 Bq/kg), and 40K (564.3 Bq/kg) were higher than the worldwide average concentrations value of these radionuclides reported by UNSCEAR, 2000. The average activity concentration value of 238U (2.35 Bq/L) and 232Th (1.85 Bq/L) in water samples was similar and comparable to their mean concentrations in the control sample collected from Nduluma River in Arusha. Najat K. Mohammed and Mohamed S. Mazunga Copyright © 2013 Najat K. Mohammed and Mohamed S. Mazunga. All rights reserved. Fri, 24 May 2013 15:34:58 +0000 http://www.hindawi.com/journals/ijac/2013/312581/ The present paper deals with the assessment of heavy metals in soil and roadside dust around Misurata City Centre and industrial areas/roads in the period of October 2011–May 2012. The levels of Pb, Fe, Zn, Ni, Cd, Cr, and Cu in settled dust samples collected near small streets, playgrounds, gas stations and main streets in the Misurata Area have been determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Also, the levels of same heavy metals in industrial areas have been determined. Metal concentration trend variation was also discussed in relation with traffic density and other sources of fugitive emission around different sites on each road/area. The overall mean concentration for main streets was significantly higher () than for other small streets, where Misurata has been the centre of fierce fighting and is located in a frontline battle zone in the Libyan war; therefore most of metal concentrations in surface soil in the fighting area Tripoli Street and Benghazi Street were higher than those from the other sites (outside fighting area). M. A. Elbagermi, H. G. M. Edwards, and A. I. Alajtal Copyright © 2013 M. A. Elbagermi et al. All rights reserved. Thu, 16 May 2013 11:08:49 +0000 http://www.hindawi.com/journals/ijac/2013/137279/ Two new, sensitive, and selective spectrofluorometric methods were developed for the determination of gemifloxacin mesylate (GFX) in tablets and spiked human plasma. Method A was based on measurement of the enhanced fluorescence spectral behaviour of GFX in a sodium dodecyl sulphate (SDS) micellar system. In aqueous solution of acetate buffer pH 5.5, the fluorescence intensity of GFX was greatly enhanced about tenfold in the presence of SDS. The fluorescence intensity was measured at 402 nm after excitation at 274 nm. Method B was based on Hantzsch condensation reaction between the primary amino group of GFX with acetylacetone and formaldehyde in acetate buffer of pH 3.5 yielding a highly yellow fluorescent derivative. The reaction of GFX with acetylacetone-formaldehyde system solution resulted in bathochromic shift of both emission (476 nm) and excitation (420 nm) wavelengths. The fluorescence intensity was directly proportional to the concentration over the range 10–1000 ng/ml and 100–2000 ng/ml for method A and B, respectively. The proposed methods were applied successfully for determination of GFX in its tablets and spiked plasma. Therefore, these methods can be considered of real interest for reliable and practical quality control analysis of GFX. Noha N. Atia, Ashraf M. Mahmoud, Salwa R. El-Shabouri, and Wesam M. El-Koussi Copyright © 2013 Noha N. Atia et al. All rights reserved. Sun, 12 May 2013 12:34:37 +0000 http://www.hindawi.com/journals/ijac/2013/743792/ A selective and simple method for separation and preconcentration of zinc ions was developed by using dispersive liquid-liquid microextraction. Parameters that have an effect on the microextraction efficiency such as volume of extraction and disperser solvent, extraction time, and adding salt were investigated. Under optimum conditions, a preconcentration factor of 250 was obtained. The limit of detection (LOD) obtained under the optimal conditions was 0.09 ng mL−1. The linearity of method was obtained in range of 0.2–50 ng mL−1 with a correlation coefficient () of 0.9974. The relative standard deviation for 10 replicate determinations at 1.0 ng mL−1 of zinc was 2.53%. The proposed method was successfully applied to the analysis of zinc in water sample. Ali Mazloomifar Copyright © 2013 Ali Mazloomifar. All rights reserved. Thu, 09 May 2013 15:27:28 +0000 http://www.hindawi.com/journals/ijac/2013/802573/ Seaweeds are important sources of carotenoids, and numerous studies have shown the beneficial effects of these pigments on human health. In the present study, Himanthalia elongata brown seaweed was extracted with a mixture of low polarity solvents, and the crude extract was separated using analytical thin-layer chromatography (TLC). The separated compounds were tested for their potential antioxidant capacity and antimicrobial activity against Listeria monocytogenes bacteria using TLC bioautography approach. For bio-autography, the coloured band on TLC chromatogram was visualized after spraying with DPPH and triphenyl-tetrazolium chloride reagents which screen antioxidant and antimicrobial compounds, respectively, and only one active compound was screened on the TLC plate. Preliminary identification of this active compound was done by comparing its colour and (retention factor) value with the authentic fucoxanthin standard. Further, the active compound was purified using preparative TLC. This purified compound showed a strong antioxidant (EC50:  g/mL) and antimicrobial (inhibition zone: 10.27 mm, 25 g compound/disc) activities, which were examined by DPPH scavenging and agar disc-diffusion bioassay, respectively. The bioactivity shown by the purified compound was almost similar to the fucoxanthin standard. The characteristic UV-visible and FT-IR spectra of the purified active compound completely matched with the standard. Hence, the main active compound in H. elongata was identified as fucoxanthin. Gaurav Rajauria and Nissreen Abu-Ghannam Copyright © 2013 Gaurav Rajauria and Nissreen Abu-Ghannam. All rights reserved. Sun, 28 Apr 2013 18:25:00 +0000 http://www.hindawi.com/journals/ijac/2013/628397/ Mercury has been determined in Ayurvedic dietary supplements (Trifala, Trifala Guggulu, Turmeric, Mahasudarshan, Yograj, Shatawari, Hingwastika, Shatavari, and Shilajit) by inductively coupled plasma-mass spectrometry (ICP-MS) and direct mercury analysis using the Hydra-C direct mercury analyzer (Teledyne Leeman Labs Hudson, NH, USA). Similar results were obtained from the two methods, but the direct mercury analysis method was much faster and safer and required no microwave digestion (unlike ICP-MS). Levels of mercury ranged from 0.002 to 56 μg/g in samples of dietary supplements. Standard reference materials Ephedra 3240 and tomato leaves that were from the National Institute of Standard and Technology (NIST) and dogfish liver (DOLT3) that was from the Canadian Research Council were analyzed using Hydra-C method. Average mercury recoveries were 102% (RSD% 0.0018), 100% (RSD% 0.0009), and 101% (RSD% 0.0729), respectively. Hydra-C method Limit Of Quantitation was 0.5 ng. Amir A. Abdalla and Robert E. Smith Copyright © 2013 Amir A. Abdalla and Robert E. Smith. All rights reserved. Sun, 25 Nov 2012 09:51:58 +0000 http://www.hindawi.com/journals/ijac/2012/840528/ Sugar cane spirits are some of the most popular alcoholic beverages consumed in Cape Verde. The sugar cane spirit industry in Cape Verde is based mainly on archaic practices that operate without supervision and without efficient control of the production process. The objective of this work was to evaluate samples of industrial and alembic sugar cane spirits from Cape Verde and Ceará, Brazil using principal component analysis. Thirty-two samples of spirits were analyzed, twenty from regions of the islands of Cape Verde and twelve from Ceará, Brazil. Of the samples obtained from Ceará, Brazil seven are alembic and five are industrial spirits. The components analyzed in these studies included the following: volatile organic compounds (n-propanol, isobutanol, isoamylic, higher alcohols, alcoholic grade, acetaldehyde, acetic acid, acetate); copper; and sulfates. Regina F. R. Pereira, Carla B. Vidal, Ari C. A. de Lima, Diego Q. Melo, Allan N. S. Dantas, Gisele S. Lopes, Ronaldo F. do Nascimento, Clerton L. Gomes, and Maria Nataniela da Silva Copyright © 2012 Regina F. R. Pereira et al. All rights reserved. Thu, 23 Aug 2012 09:22:33 +0000 http://www.hindawi.com/journals/ijac/2012/690356/ Trimethylsilanol (TMSOH) can cause damage to surfaces of scanner lenses in the semiconductor industry, and there is a critical need to measure and control airborne TMSOH concentrations. This study develops a thermal desorption (TD)-gas chromatography (GC)-mass spectrometry (MS) method for measuring trace-level TMSOH in occupational indoor air. Laboratory method optimization obtained best performance when using dual-bed tube configuration (100 mg of Tenax TA followed by 100 mg of Carboxen 569), n-decane as a solvent, and a TD temperature of 300°C. The optimized method demonstrated high recovery (87%), satisfactory precision (<15% for spiked amounts exceeding 1 ng), good linearity (𝑅2=0.9999), a wide dynamic mass range (up to 500 ng), low method detection limit (2.8 ng m−3 for a 20-L sample), and negligible losses for 3-4-day storage. The field study showed performance comparable to that in laboratory and yielded first measurements of TMSOH, ranging from 1.02 to 27.30 𝜇g/m3, in the semiconductor industry. We suggested future development of real-time monitoring techniques for TMSOH and other siloxanes for better maintenance and control of scanner lens in semiconductor wafer manufacturing. Jae Hwan Lee, Chunrong Jia, Yong Doo Kim, Hong Hyun Kim, Tien Thang Pham, Young Seok Choi, Young Un Seo, and Ike Woo Lee Copyright © 2012 Jae Hwan Lee et al. All rights reserved. Sun, 22 Jul 2012 13:13:27 +0000 http://www.hindawi.com/journals/ijac/2012/156201/ Norberto P. Lopes, Ernani Pinto, Michael Niehues, Paul J. Gates, and Ricardo Vessecchi Copyright © 2012 Norberto P. Lopes et al. All rights reserved. Sun, 24 Jun 2012 09:52:08 +0000 http://www.hindawi.com/journals/ijac/2012/390182/ This review captures the use of live cells as dynamic microlaboratories through implementation of labeled nanoparticles (nanosensors) that have both sensing and targeting functions. The addition of 2,4-ε-dinitrophenol-L-lysine (DNP) as a FcεRI targeting ligand and 4-mercaptopyridine (4-MPy) as a pH-sensing ligand enables spatial and temporal monitoring of FcεRI receptors and their pH environment within the endocytic pathway. To ensure reliability, the sensor is calibrated in vivo using the ionophore nigericin and standard buffer solutions to equilibrate the external [H+] concentration with that of the cell compartments. This review highlights the nanosensors, ability to traffic and respond to pH of receptor-bound nanosensors (1) at physiological temperature (37∘C) versus room temperature (25∘C), (2) after pharmacological treatment with bafilomycin, an H+ ATPase pump inhibitor, or amiloride, an inhibitor of Na+/H+ exchange, and (3) in response to both temperature and pharmacological treatment. Whole-cell, time lapse images are demonstrated to show the ability to transform live cells into dynamic laboratories to monitor temporal and spatial endosomal pH. The versatility of these probes shows promise for future applications relevant to intracellular trafficking and intelligent drug design. Kristy L. Nowak-Lovato and Kirk D. Rector Copyright © 2012 Kristy L. Nowak-Lovato and Kirk D. Rector. All rights reserved. Thu, 10 May 2012 09:45:13 +0000 http://www.hindawi.com/journals/ijac/2012/205101/ A strategy for analyzing flavone C-glucosides in the leaves of different species of bamboo was developed. Firstly, the flavone C-glycosides were extracted from the bamboo leaves (51 species in 17 genera) with methanol and chromatographed on silica gel 60 plates in automatic developing chamber (ADC2), and a qualitative survey using simple derivatization steps with the NP reagent was carried out. The flavone C-glycosides were found in 40 of 51 species of bamboo examined. Secondly, an HPLC method with photodiode array and multiple wavelength detector was optimized and validated for the simultaneous determination of flavone C-glycosides, including isoorientin, isovitexin, orientin, and vitexin in the leaves of three species of bamboo and the flavone C-glycosides were confirmed by LC/MS. The optimized HPLC method proved to be linear in the concentration range tested (0.2–100 μg/mL, 𝑟2≥0.9997), precise (RSD≤1.56%), and accurate (88–106%). The concentration ranges of isoorientin, isovitexin, orientin, and vitexin in three bamboo leaves samples were 1.00–2.78, 0–0.31, 0–0.07, and 0.20–0.68 mg/g, respectively. The proposed method was validated to be simple and reliable and can be a tool for quality control of bamboo leaf extract or its commercial products. Jin Wang, Yong-de Yue, Hao Jiang, and Feng Tang Copyright © 2012 Jin Wang et al. All rights reserved. Thu, 03 May 2012 11:44:15 +0000 http://www.hindawi.com/journals/ijac/2012/154907/ Eman Y. Z. Frag, Gehad G. Mohamed, Mohamed M. Khalil, and Mohammad M. A. Hwehy Copyright © 2012 Eman Y. Z. Frag et al. All rights reserved. Mon, 23 Apr 2012 12:08:39 +0000 http://www.hindawi.com/journals/ijac/2012/382021/ Paper Spray Ionization is an atmospheric pressure ionization technique that utilizes an offline electro-osmotic flow to generate ions off a paper medium. This technique can be performed on a Bruker SolariX Fourier transform ion cyclotron resonance mass spectrometer by modifying the existing nanospray source. High-resolution paper spray spectra were obtained for both organic and biological samples to demonstrate the benefit of linking the technique with a high-resolution mass analyzer. Error values in the range 0.23 to 2.14 ppm were obtained for calf lung surfactant extract with broadband mass resolving power (m/Δm50%) above 60,000 utilizing an external calibration standard. Kevin D. Quinn, Charmion I. Cruickshank, and Troy D. Wood Copyright © 2012 Kevin D. Quinn et al. All rights reserved. Sun, 08 Apr 2012 15:55:01 +0000 http://www.hindawi.com/journals/ijac/2012/376381/ Tin content in samples of canned fruits and vegetables was determined by hydride generation inductively coupled plasma atomic emission spectrometry (HG-ICP-OES), and it was compared with results obtained by standard method of flame atomic absorption spectrometry (AAS). Selected tin emission lines intensity was measured in prepared samples after addition of tartaric acid and followed by hydride generation with sodium borohydride solution. The most favorable line at 189.991 nm showed the best detection limit (1.9 μg L−1) and limit of quantification (6.4 μg kg−1). Good linearity and sensitivity were established from time resolved analysis and calibration tests. Analytical accuracy of 98–102% was obtained by recovery study of spiked samples. Method of standard addition was applied for tin determination in samples from fully protected tinplate. Tin presence at low-concentration range was successfully determined. It was shown that tenth times less concentrations of Sn were present in protected cans than in nonprotected or partially protected tinplate. Sanda Rončević, Anica Benutić, Ivan Nemet, and Buga Gabelica Copyright © 2012 Sanda Rončević et al. All rights reserved. Thu, 05 Apr 2012 15:20:28 +0000 http://www.hindawi.com/journals/ijac/2012/375831/ We investigated the electrochemical behavior of hemoglobin by glassy carbon electrode modified with Mn2O3-Ag nanofibers. The Mn2O3-Ag nanofibers were used as facilitator electron transfer between Hb and glassy-carbon-modified electrode. The Mn2O3-Ag nanofibers are studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The hemoglobin showed a quasireversible electrochemical redox behavior with a formal potential of −49 mV (versus Ag/AgCl) in 0.1 M potassium phosphate buffer solution at pH 7.0. The designed biosensor possesses good stability and reproducibility and achieves 95% of the steady-state current in less than five seconds. Masoud Negahdary, Gholamreza Mazaheri, Somyyeh Rad, Mohammadreza Hadi, Roya Malekzadeh, Mohammad Mahdi Saadatmand, Saeed Rezaei-Zarchi, Fariba Pishbin, and Mojdeh Khosravian-hemami Copyright © 2012 Masoud Negahdary et al. All rights reserved. Thu, 22 Mar 2012 11:03:13 +0000 http://www.hindawi.com/journals/ijac/2012/592650/ A competitive CZE method for quality control analysis of multivitamin preparations and veterinary products containing B-group vitamins was developed. Vitamins of interest are thiamine hydrochloride (B1), thiamine monophosphate chloride (B1a), riboflavine (B2), riboflavine-5′monophosphate (B2a), nicotinamide (B3), d-pantothenic acid calcium salt (B5), pyridoxine hydrochloride (B6), folic acid (B9), and 4-aminobenzoic acid (B10). These analytes were separated optimizing the experimental conditions in 20 mM tetraborate buffer pH=9.2 as a BGE (background electrolyte), on a Beckman P/ACE System MDQ instrument, using uncoated fused silica capillary. The effective capillary length was of 49.5 cm, I.D.=50 μm, the applied voltage 20 kV and the temperature 25∘C. Detection was performed by a diode array detector at 214 nm for all vitamins except B5 (190 nm) and B2a (260 nm). Separation time was about 9 min. After experimental conditions optimization, the proposed method was validated. Precision of migration time and corrected peak area, linearity range, LOD and LOQ, accuracy (recovery), robustness, and ruggedness were evaluated for each analyte demonstrating the good reliability of the method. Analyses of the pharmaceutical real samples were performed and confirmed the versatility of this method. Marina Franco, Renata Jasionowska, and Elisa Salvatore Copyright © 2012 Marina Franco et al. All rights reserved. Sun, 18 Mar 2012 10:59:17 +0000 http://www.hindawi.com/journals/ijac/2012/495043/ The work presented in this paper is part of the study which aims at determining the levels of elements in hair of children in Tanzania as a bioindicator of their nutrition and health. In this paper, the levels of trace elements in hair from children living in Dar es Salaam have been analysed. The analysis was carried out by long and short irradiation INAA at the reactor centre of the Institute of Nuclear Physics, Rez Czech Republic. 22 samples were collected from children living at Kiwalani about 12 km from Dar es Salaam city and 16 samples from children living at Mlimani, the main campus of University of Dar es Salaam. A total of 34 elements were found in the hair of the children. There were no big differences between the concentration levels of the essential elements in hair samples collected from the children which might indicate the same food consumption habits. Najat K. Mohammed Copyright © 2012 Najat K. Mohammed. All rights reserved. Sun, 18 Mar 2012 10:47:28 +0000 http://www.hindawi.com/journals/ijac/2012/721494/ The major secondary metabolites and fatty acids occurring in the seeds of Virola surinamensis were monitored by GC-MS during germination and seedling development. The role as carbon source for seedling development was indicated considering that both classes of compounds were similarly consumed in the seeds and that no selective consumption of compounds could be detected. Massuo Jorge Kato, Massayoshi Yoshida, Norberto Peporine Lopes, Denise Brentan da Silva, and Alberto José Cavalheiro Copyright © 2012 Massuo Jorge Kato et al. All rights reserved. Thu, 15 Mar 2012 09:39:05 +0000 http://www.hindawi.com/journals/ijac/2012/923208/ We take advantage of polyelectrolyte feature exhibited by natural cashew gum (Anacardium occidentale L.) (CG), found in northeast Brazil, to employ it in the formation of electroactive nanocomposites prepared by layer-by-layer (LbL) technique. We used polyaniline unmodified (PANI) or modified with phosphonic acid (PA), PANI-PA as cationic polyelectrolyte. On the other hand, the CG or polyvinyl sulfonic (PVS) acids were used as anionic polyelectrolytes. The films were prepared with PANI or PANI-PA intercalated with CG or with PVS alternately resulting in four films with different sequences: PANI/CG PANI-PA/CG, PANI/PVS and PANI-PA/PVS, respectively. Analysis by cyclic voltammetry (CV) of the films showed that the presence of gum increases the stability of the films in acidic medium. The performance of the modified electrode of PANI-PA/CG was evaluated in electro analytical determination of dopamine (DA). The tests showed great sensitivity of the film for this analyte that was detected at 10−5 mol L−1. Sergio Bitencourt Araújo Barros, Cleide Maria da Silva Leite, Ana Cristina Facundo de Brito, José Ribeiro Dos Santos Júnior, Valtencir Zucolotto, and Carla Eiras Copyright © 2012 Sergio Bitencourt Araújo Barros et al. All rights reserved. Mon, 12 Mar 2012 16:04:22 +0000 http://www.hindawi.com/journals/ijac/2012/282574/ The Electrospray Ionization (ESI) is a soft ionization technique extensively used for production of gas phase ions (without fragmentation) of thermally labile large supramolecules. In the present review we have described the development of Electrospray Ionization mass spectrometry (ESI-MS) during the last 25 years in the study of various properties of different types of biological molecules. There have been extensive studies on the mechanism of formation of charged gaseous species by the ESI. Several groups have investigated the origin and implications of the multiple charge states of proteins observed in the ESI-mass spectra of the proteins. The charged analytes produced by ESI can be fragmented by activating them in the gas-phase, and thus tandem mass spectrometry has been developed, which provides very important insights on the structural properties of the molecule. The review will highlight recent developments and emerging directions in this fascinating area of research. Shibdas Banerjee and Shyamalava Mazumdar Copyright © 2012 Shibdas Banerjee and Shyamalava Mazumdar. All rights reserved. Mon, 27 Feb 2012 12:45:09 +0000 http://www.hindawi.com/journals/ijac/2012/981758/ Optimized and validated spectrophotometric methods have been proposed for the determination of iron and cobalt individually and simultaneously. 2-hydroxy-1-naphthaldehyde-p-hydroxybenzoichydrazone (HNAHBH) reacts with iron(II) and cobalt(II) to form reddish-brown and yellow-coloured [Fe(II)-HNAHBH] and [Co(II)-HNAHBH] complexes, respectively. The maximum absorbance of these complexes was found at 405 nm and 425 nm, respectively. For [Fe(II)-HNAHBH], Beer’s law is obeyed over the concentration range of 0.055–1.373 μg mL−1 with a detection limit of 0.095 μg mL−1 and molar absorptivity ɛ, 5.6 × 104 L mol−1 cm−1. [Co(II)-HNAHBH] complex obeys Beer’s law in 0.118–3.534 μg mL−1 range with a detection limit of 0.04 μg mL−1 and molar absorptivity, ɛ of 2.3 × 104 L mol−1 cm−1. Highly sensitive and selective first-, second- and third-order derivative methods are described for the determination of iron and cobalt. A simultaneous second-order derivative spectrophotometric method is proposed for the determination of these metals. All the proposed methods are successfully employed in the analysis of various biological, water, and alloy samples for the determination of iron and cobalt content. V. S. Anusuya Devi and V. Krishna Reddy Copyright © 2012 V. S. Anusuya Devi and V. Krishna Reddy. All rights reserved. Thu, 23 Feb 2012 11:53:12 +0000 http://www.hindawi.com/journals/ijac/2012/363919/ Several studies involving the family Verbenaceae, occurring in the Brazilian Cerrado, have emphasized the popular use of many aromatic species. We highlight the use of Lippia sidoides Cham., known as “alecrim pimenta,” native to northeastern Brazil and northern Minas Gerais. Leaves of this species were collected in antropized Brazilian Cerrado area, in Hidrolândia, Goiás, and their essential oils were extracted by hydrodistillation in a Clevenger-type apparatus and thereafter analyzed GC/MS. Among the compounds identified in this study were the most abundant oxygenated monoterpenes, followed by sesquiterpenes hydrocarbons. The oxygenated monoterpene 1,8-cineole was the major constituent followed by isoborneol and bornyl acetate. The chemical composition of essential oil described in this paper differs from that described in the literature for L. sidoides found in its native environment, where the major constituents are thymol and carvacrol. Sandra Ribeiro de Morais, Thiago Levi Silva Oliveira, Maria Teresa Freitas Bara, Edemilson Cardoso da Conceição, Maria Helena Rezende, Pedro Henrique Ferri, and José Realino de Paula Copyright © 2012 Sandra Ribeiro de Morais et al. All rights reserved. Tue, 21 Feb 2012 13:26:13 +0000 http://www.hindawi.com/journals/ijac/2012/259217/ Flavonoids are one of the most important classes of natural products having a wide variety of biological activities. There is wide interest in a range of medical and dietary applications, and having a rapid, reliable method for structural elucidation is essential. In this study a range of flavonoid standards are investigated by chip-based negative ion nanospray mass spectrometry. It was found that the different classes of flavonoid studied have a combination of distinct neutral losses from the precursor ion [M-H]− along with characteristic low-mass ions. By looking only for this distinct pattern of product ions, it is possible to determine the class of flavonoid directly. This methodology is tested here by the analysis of a green tea extract, where the expected flavonoids were readily identified, along with quercetin, which is shown to be present at only about 2% of the most intense ion in the spectrum. Paul J. Gates and Norberto P. Lopes Copyright © 2012 Paul J. Gates and Norberto P. Lopes. All rights reserved. Mon, 20 Feb 2012 12:04:44 +0000 http://www.hindawi.com/journals/ijac/2012/918292/ Two flow methods, based, respectively, on flow-injection analysis (FIA) and on multicommutated flow analysis (MCFA), were compared with regard to their use for the determination of total selenium in infant formulas by hydride-generation atomic absorption spectrometry. The method based on multicommutation provided lower detection and quantification limits (0.08 and 0.27 μg L−1 compared to 0.59 and 1.95 μ L−1, resp.), higher sampling frequency (160 versus. 70 samples per hour), and reduced reagent consumption. Linearity, precision, and accuracy were similar for the two methods compared. It was concluded that, while both methods proved to be appropriate for the purpose, the MCFA-based method exhibited a better performance. Mariela Pistón and Moisés Knochen Copyright © 2012 Mariela Pistón and Moisés Knochen. All rights reserved. Mon, 20 Feb 2012 08:27:22 +0000 http://www.hindawi.com/journals/ijac/2012/408057/ The interaction between Avelox and bovine serum albumin (BSA) was investigated at different temperatures by fluorescence spectroscopy. Results showed that Avelox could quench the intrinsic fluorescence of BSA strongly, and the quenching mechanism was a static quenching process with Förester spectroscopy energy transfer. The electrostatic force played an important role on the conjugation reaction between BSA and Avelox. The order of magnitude of binding constants (𝐾𝑎) was 104, and the number of binding site (𝑛) in the binary system was approximately equal to 1. The binding distance (𝑟) was less than 3 nm and the primary binding site for Avelox was located in subdomain IIA of BSA. Synchronous fluorescence spectra clearly revealed that the microenvironment of amino acid residues and the conformation of BSA were changed during the binding reaction. In addition, the effect of some antibiotics on the binding constant of Avelox with BSA was also studied. Baosheng Liu, Chao Yang, Xiaona Yan, Jing Wang, and Yunkai Lv Copyright © 2012 Baosheng Liu et al. All rights reserved. Tue, 14 Feb 2012 11:22:49 +0000 http://www.hindawi.com/journals/ijac/2012/260425/ Matrix-assisted laser desorption/ionization (MALDI) tof mass spectrometry was used for the confirmation of hapten number in synthesized antigen. As application of MAb, the MAbs against ginsenosides and glycyrrhizin have been prepared resulting in the development of two new techniques that we named the eastern blotting method and the knockout extract preparation. In eastern blotting technique, glycosides like ginsenosides and glycyrrhizin separated by silica gel TLC were blotted to PVDF membrane that was treated with a NaIO4 solution followed by BSA resulted in glycoside-BSA conjugate on a PVDF membrane. The blotted spots were stained by MAb. Double staining of eastern blotting for ginsenosides using antiginsenoside Rb1 and Rg1 MAbs promoted complete identification of ginsenosides in Panax species. The immunoaffinity concentration of glycyrrhizin was determined by immunoaffinity column conjugated with antiglycyrrhizin MAb resulting in the glycyrrhizin-knockout extract, which was determined by the synergic effect with glycyrrhizin on NO production using the cell line. Hiroyuki Tanaka, Osamu Morinaga, Takuhiro Uto, Shunsuke Fuji, Frederick Asare Aboagye, Nguyen Huu Tung, Xiao Wei Li, Waraporn Putalun, and Yukihiro Shoyama Copyright © 2012 Hiroyuki Tanaka et al. All rights reserved. Thu, 09 Feb 2012 14:34:43 +0000 http://www.hindawi.com/journals/ijac/2012/809513/ A liquid chromatographic procedure has been developed for the determination of carbaryl, a phenyl-N-methylcarbamate, and its main metabolite 1-naphthol, using a C18 column (250 mm  ×  4.6 mm) with a micellar mobile phase and fluorescence detection at maximum excitation/emission wavelengths of 225/333 nm, respectively. In the optimization step, surfactants sodium dodecyl sulphate (SDS), Brij-35 and N-cetylpyridinium chloride monohydrate, and organic solvents propanol, butanol, and pentanol were considered. The selected mobile phase was 0.15 M SDS-6% (v/v)-pentanol-0.01 M NaH2PO4 buffered at pH 3. Validation studies, according to the ICH Tripartite Guideline, included linearity (𝑟>0.999), limit of detection (5 and 18 ng mL−1, for carbaryl and 1-naphthol, resp.), and limit of quantification (15 and 50 ng mL−1, for carbaryl and 1-naphthol, resp.), with intra- and interday precisions below 1%, and robustness parameters below 3%. The results show that the procedure was adequate for the routine analysis of these two compounds in water, soil, and vegetables samples. Mei-Liang Chin-Chen, Maria Rambla-Alegre, Abhilasha Durgbanshi, Devasish Bose, Sandeep K. Mourya, Josep Esteve-Romero, and Samuel Carda-Broch Copyright © 2012 Mei-Liang Chin-Chen et al. All rights reserved. Wed, 08 Feb 2012 18:13:52 +0000 http://www.hindawi.com/journals/ijac/2012/341260/ Immunoimaging scanning probe microscopy was utilized for the low-level detection and quantification of biotinylated G4 poly(amidoamine) PAMAM dendrimers. Results were compared to those of high-performance liquid chromatography (HPLC) and found to provide a vastly improved analytical method for the low-level detection of dendrimers, improving the limit of detection by a factor of 1000 (LOD=2.5×10−13 moles). The biorecognition method is reproducible and shows high specificity and good accuracy. In addition, the capture assay platform shows a promising approach to patterning dendrimers for nanotechnology applications. Chevelle A. Cason, Thomas A. Fabré, Andrew Buhrlage, Kristi L. Haik, and Heather A. Bullen Copyright © 2012 Chevelle A. Cason et al. All rights reserved. Wed, 08 Feb 2012 14:47:43 +0000 http://www.hindawi.com/journals/ijac/2012/546282/ An efficient and environmentally friendly sample preparation method based on the application of hydrophobic 1-Hexylpyridinium hexafluorophosphate [Hpy][PF6] ionic liquid (IL) as a microextraction solvent was proposed to preconcentrate terazosin. The performance of the microextraction method was improved by introducing a common ion of pyridinium IL into the sample solution. Due to the presence of the common ion, the solubility of IL significantly decreased. As a result, the phase separation successfully occurred even at high ionic strength, and the volume of the settled IL-phase was not influenced by variations in the ionic strength (up to 30% w/v). After preconcentration step, the enriched phase was introduced to the spectrofluorimeter for the determination of terazosin. The obtained results revealed that this system did not suffer from the limitations of that in conventional ionic-liquid microextraction. Under optimum experimental conditions, the proposed method provided a limit of detection (LOD) of 0.027 μg L−1 and a relative standard deviation (R.S.D.) of 2.4%. The present method was successfully applied to terazosin determination in actual pharmaceutical formulations and biological samples. Considering the large variety of ionic liquids, the proposed microextraction method earns many merits, and will present a wide application in the future. Mohsen Zeeb and Mahdi Sadeghi Copyright © 2012 Mohsen Zeeb and Mahdi Sadeghi. All rights reserved.