International Journal of Analytical Chemistry http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Analytical Performances of Nanostructured Gold Supported on Metal Oxide Sorbents for the Determination of Gaseous Mercury Sun, 06 Apr 2014 14:03:33 +0000 http://www.hindawi.com/journals/ijac/2014/490291/ Nanostructured gold supported TiO2, ZnO, and Al2O3 materials (1% w/w Au) were tested as sorbents for gaseous mercury (Hg) trapping and preconcentration. Their analytical performances were first compared with the one of traditional gold wool trap for the quantification of Hg standards injected into the argon flow followed by thermal desorption at 600°C and CVAFS detection. Good linearity and reproducibility were obtained, especially for Au/TiO2 material (; slope: 1.39) in the volume range of 10 to 60 µL (132–778 pg Hg). This latter even showed a better performance compared to pure Au in the volume range of 10 to 100 µL (132–1329 pg Hg) when the carrier gas flow was increased from 60 to 100 mL . The method detection limit (MDL) obtained with Au/TiO2 trap (0.10 pg ) was suitable for total gaseous mercury (TGM) determination. Au/TiO2 was, therefore, used in trapping and determining TGM in collected air samples. TGM values in the samples ranged from 6 to 10 ng . Similar results were obtained with the commercial gold-coated sand trap which showed an average TGM concentration of  ng . Julien Lusilao-Makiese, Emmanuel Tessier, David Amouroux, and Ewa Cukrowska Copyright © 2014 Julien Lusilao-Makiese et al. All rights reserved. Determination of Acid Dissociation Constants () of Bicyclic Thiohydantoin-Pyrrolidine Compounds in 20% Ethanol-Water Hydroorganic Solvent Sun, 30 Mar 2014 07:42:00 +0000 http://www.hindawi.com/journals/ijac/2014/634194/ The acid dissociation constants of potential bioactive fused ring thiohydantoin-pyrrolidine compounds were determined by potentiometric titration in 20% (v/v) ethanol-water mixed at °C, at an ionic background of 0.1 mol/L of NaCl using the HYPERQUAD computer program. Proton affinities of potential donor atoms of the ligands were calculated by AM1 and PM3 semiempiric methods. We found, potentiometrically, three different acid dissociation constants for 1a–f. We suggest that these acid dissociation constants are related to the carboxyl, enol, and amino groups. Yahya Nural, H. Ali Döndaş, Hayati Sarı, Hasan Atabey, Samet Belveren, and Müge Gemili Copyright © 2014 Yahya Nural et al. All rights reserved. Trace Analysis in End-Exhaled Air Using Direct Solvent Extraction in Gas Sampling Tubes: Tetrachloroethene in Workers as an Example Tue, 18 Mar 2014 12:17:41 +0000 http://www.hindawi.com/journals/ijac/2014/904512/ Simple and cost-effective analytical methods are required to overcome the barriers preventing the use of exhaled air in routine occupational biological monitoring. Against this background, a new method is proposed that simplifies the automation and calibration of the analytical measurements. End-exhaled air is sampled using valveless gas sampling tubes made of glass. Gaseous analytes are transferred to a liquid phase using a microscale solvent extraction performed directly inside the gas sampling tubes. The liquid extracts are analysed using a gas chromatograph equipped, as usual, with a liquid autosampler, and liquid standards are used for calibration. For demonstration purposes, the method’s concept was applied to the determination of tetrachloroethene in end-exhaled air, which is a biomarker for occupational tetrachloroethene exposure. The method’s performance was investigated in the concentration range 2 to 20 μg tetrachloroethene/L, which corresponds to today’s exposure levels. The calibration curve was linear, and the intra-assay repeatability and recovery rate were sufficient. Analysis of real samples from dry-cleaning workers occupationally exposed to tetrachloroethene and from nonexposed subjects demonstrated the method’s utility. In the case of tetrachloroethene, the method can be deployed quickly, requires no previous experiences in gas analysis, provides sufficient analytical reliability, and addresses typical end-exhaled air concentrations from exposed workers. Chris-Elmo Ziener and Pia-Paulin Braunsdorf Copyright © 2014 Chris-Elmo Ziener and Pia-Paulin Braunsdorf. All rights reserved. Determination of β-Galactooligosaccharides by Liquid Chromatography Wed, 26 Feb 2014 09:37:14 +0000 http://www.hindawi.com/journals/ijac/2014/768406/ Beta-galactooligosaccharides (GOS) are oligosaccharides normally produced industrially by transgalactosylation of lactose. They are also present naturally in the milk of many animals including humans and cows. GOS are thought to be good for health, being potential prebiotic fibres, and are increasingly added to food products. In order to control the GOS content of products, the AOAC official method 2001.02 was developed. However, the method has some shortcomings and in particular is unsuited to the analysis of products containing high levels of lactose such as infant formula. To overcome this problem, we developed a new method for application to infant formula and tested it on various GOS ingredients as well as infant formulae. When applied to GOS ingredients the results of the new method compare well with those of the official AOAC method, typically giving results in the range 90–110% of those of the official method and having an expanded measurement uncertainty of less than 15%. For three products, the results were outside this range (recoveries of 80–120% and expended measurement uncertainties up to 20%). When applied to the analysis of infant formula, recoveries were in the range of 92–102% and the expanded measurement uncertainties were between 4.2 and 11%. Sean Austin, Thierry Bénet, Julien Michaud, Denis Cuany, and Philippe Rohfritsch Copyright © 2014 Sean Austin et al. All rights reserved. Study of a Conformational Equilibrium of Lisinopril by HPLC, NMR, and DFT Tue, 25 Feb 2014 00:00:00 +0000 http://www.hindawi.com/journals/ijac/2014/494719/ The isomerization of lisinopril has been investigated using chromatographic, NMR spectroscopic, and theoretical calculations. The NMR data, particularly the NOEDIFF experiments, show that the major species that was eluted first is the trans form. The proportion was 77% and 23% for the trans and cis, respectively. The thermodynamic parameters (, , and ) were determined by varying the temperature in the NMR experiments. The interpretations of the experimental data were further supported by DFT/B3LYP calculations. Sondes Bouabdallah, Med Thaieb Ben Dhia, and Med Rida Driss Copyright © 2014 Sondes Bouabdallah et al. All rights reserved. Four Derivative Spectrophotometric Methods for the Simultaneous Determination of Carmoisine and Ponceau 4R in Drinks and Comparison with High Performance Liquid Chromatography Wed, 12 Feb 2014 00:00:00 +0000 http://www.hindawi.com/journals/ijac/2014/650465/ Four simple, rapid, and accurate spectrophotometric methods were developed for the simultaneous determination of two food colorants, Carmoisine (E122) and Ponceau 4R (E124), in their binary mixtures and soft drinks. The first method is based on recording the first derivative curves and determining each component using the zero-crossing technique. The second method uses the first derivative of ratio spectra. The ratio spectra are obtained by dividing the absorption spectra of the binary mixture by that of one of the components. The third method, derivative differential procedure, is based on the measurement of difference absorptivities derivatized in first order of solution of drink samples in 0,1 N NaOH relative to that of an equimolar solution in 0,1 N HCl at wavelengths of 366 and 451 nm for Carmoisine and Ponceau 4R, respectively. The last method, based on the compensation method is presented for derivative spectrophotometric determination of E122 and E124 mixtures with overlapping spectra. By using ratios of the derivative maxima, the exact compensation of either component in the mixture can be achieved, followed by its determination. These proposed methods have been successfully applied to the binary mixtures and soft drinks and the results were statistically compared with the reference HPLC method (NMKL 130). Fatma Turak, Mithat Dinç, Öznur Dülger, and Mahmure Ustun Özgür Copyright © 2014 Fatma Turak et al. All rights reserved. Synthesis of 6-(2-Methoxynaphthyl)-2,3-dihydro-1,2,4-triazine-3-thione as a New Reagent for Spectrophotometric Determination of Copper Tue, 04 Feb 2014 00:00:00 +0000 http://www.hindawi.com/journals/ijac/2014/260179/ A simple, sensitive, accurate, and green spectrophotometric method for the determination of Cu(II) using newly synthesized reagent, 6-(2-methoxynaphthyl)-2,3-dihydro-1,2,4-triazine-3-thione (MNDTT), has been developed. MNDTT was synthesized based on the acylation of methoxy naphthalene and reaction of the product with amyl nitrite, which upon reaction with thiosemicarbazide yielded 6-(2-meyhoxynaphthyl)-2,3-dihydro-1,2,4-triazine-3-thione. MNDTT produces a dark red complex with copper in methanol according to the 1 : 2 stoichiometry. Beer’s law was obeyed over the concentration range of 2.5–20 µg/mL with . The limit of detection and limit of quantification were 0.33 and 1.10 µg/mL, respectively. Within-day and between-day precision values were less than 3.68%. Finally, the method has been applied to a dental alloy (110-plus) successfully and the results were compared with atomic absorption method. The results showed that there was no significant difference between the two methods (). Maliheh Barazandeh Tehrani, Hutan Ghanbari, Effat Souri, Fazel Shamsa, and Mohsen Amini Copyright © 2014 Maliheh Barazandeh Tehrani et al. All rights reserved. Analysis of Five Earthy-Musty Odorants in Environmental Water by HS-SPME/GC-MS Thu, 02 Jan 2014 15:08:54 +0000 http://www.hindawi.com/journals/ijac/2014/697260/ The pressing issue of earthy and musty odor compounds in natural waters, which can affect the organoleptic properties of drinking water, makes it a public health concern. A simple and sensitive method for simultaneous analysis of five odorants in environmental water was developed by headspace solid-phase microextraction (HS-SPME) coupled to chromatography-mass spectrometry (GC-MS), including geosmin (GSM) and 2-methylisoborneol (2-MIB), as well as dimethyl trisulfide (DMTS), β-cyclocitral, and β-ionone. Based on the simple modification of original magnetic stirrer purchased from CORNING (USA), the five target compounds can be separated within 23 min, and the calibration curves show good linearity with a correlation coefficient above 0.999 (levels = 5). The limits of detection (LOD) are all below 1.3 ng L−1, and the relative standard deviation (%RSD) is between 4.4% and 9.9% () and recoveries of the analytes from water samples are between 86.2% and 112.3%. In addition, the storage time experiment indicated that the concentrations did not change significantly for GSM and 2-MIB if they were stored in canonical environment. In conclusion, the method in this study could be applied for monitoring these five odorants in natural waters. Zhen Ding, Shifu Peng, Weiwen Xia, Hao Zheng, Xiaodong Chen, and Lihong Yin Copyright © 2014 Zhen Ding et al. All rights reserved. Titrimetric and Spectrophotometric Methods for the Assay of Ketotifen Using Cerium(IV) and Two Reagents Tue, 12 Nov 2013 09:56:25 +0000 http://www.hindawi.com/journals/ijac/2013/697651/ One titrimetric and two spectrophotometric methods are described for the determination of ketotifen fumarate (KTF) in bulk drug and in tablets using cerium(IV) as the oxidimetric agent. In titrimetry (method A), the drug was treated with a measured excess of cerium(IV) in H2SO4 medium and after a standing time of 10 min, the surplus oxidant was determined by back titration with iron(II). The spectrophotometric procedures involve addition of a known excess of cerium(IV) to KTF in acid medium followed by the determination of unreacted oxidant by reacting with either p-dimethyl amino benzaldehyde and measuring the resulting colour at 460 nm (method B) or o-dianisidine and subsequent measurement of the absorbance of coloured product at 470 nm (method C). Titrimetric assay is based on a 1 : 2 reaction stoichiometry between KTF and cerium(IV) and the method is applicable over 2–18 mg range. In spectrophotometry, regression analysis of Beer’s law plots showed a good correlation in 0.4–8.0 and 0.4–10.0 g mL−1 KTF ranges for method B and method C, respectively, and the corresponding molar absorptivity coefficients are calculated to be and  L mol−1 cm−1. Madihalli Srinivas Raghu, Kanakapura Basavaiah, Kudige Nagaraj Prashanth, and Kanakapura Basavaiah Vinay Copyright © 2013 Madihalli Srinivas Raghu et al. All rights reserved. The Rate of Decolorization of a Radical Ion Reagent Was Used to Determine the Phenolic Content of Various Food Extracts Thu, 24 Oct 2013 10:38:25 +0000 http://www.hindawi.com/journals/ijac/2013/978968/ Polyphenols are among the most valuable and widely studied food components. In the laboratory, they are readily extractable with aqueous alcohol. An aliquot rapidly decolorizes a measured portion of ABTS, a stable deep blue radical ion. The semilog plot of light absorption versus time is typically a straight line, and an immediately evident slope provides rapid classification in terms of gallic acid equivalents. Experimental data are presented to show general agreement with the literature. The disproportionate concentration of antioxidant in the skins and peels of fruits, vegetables, and nuts is given special attention. Arthur Bradley Copyright © 2013 Arthur Bradley. All rights reserved. Liquid Chromatography/Tandem Mass Spectrometry Method for Quantitation of Cremophor EL and Its Applications Sun, 28 Jul 2013 14:08:17 +0000 http://www.hindawi.com/journals/ijac/2013/135613/ A rapid sensitive and selective MRM based method for the determination of Cremophor EL (CrEL) in rat plasma was developed using liquid chromatography/tandem mass spectrometry (LC-MS/MS). CrEL and polypropylene glycol (internal standard) were extracted from rat plasma with acetonitrile and analysed on C18 column (XBridge, 50 × 4.6 mm, 3.5 μm). The most abundant molecular ions corresponding to PEG oligomers at m/z 828, 872, 916 and 960 with daughter ion at m/z 89 were selected for multiple reaction monitoring (MRM) in electrospray mode of ionisation. Plasma concentrations of CrEL were quantified after administration through oral and intravenous routes in male sprague dawley rats at a dose of 0.26 g/kg. The standard curve was linear (0.9972) over the concentration range of 1.00 to 200 μg/mL. The lower limit of quantitation for CrEL was 1.00 μg/mL using 50 μL plasma. The coefficient of variation and relative error for inter and intra assay at three QC levels were 0.69 to 9.21 and −7.60 to 4.74 respectively. A novel proposal was conveyed to the scientific community, where formulation excipient can be analysed as qualifier in the analysis of NCEs to address the spiky plasma concentration profiles. V. Vijaya Bhaskar and Anil Middha Copyright © 2013 V. Vijaya Bhaskar and Anil Middha. All rights reserved. Investigation of Luminescence Characteristics of Osmium(II) Complexes in the Presence of Heparin Polyanions Tue, 16 Jul 2013 10:35:33 +0000 http://www.hindawi.com/journals/ijac/2013/419716/ The luminescence characteristics of six osmium carbonyl complexes with phenanthroline (phen) or bipyridine (bpy) and pyridine (py), 4-phenylpyridine (4-phpy), or triphenylphosphine (PPh3) complexes in the presence of polyanion heparin were studied in both ethanol and aqueous solutions. The influence of heparin on the luminescence of the complexes is heavily dependent on the type of ligands in the complexes and the solvent used. In the ethanol solutions, the heparin solution enhanced the luminescence of the five osmium complexes, with the strongest enhancement to the 4-phenylpyridine complexes; linear curves were obtained in the luminescence enhancement ratio () versus the heparin concentration range of 1–40 μg/mL. In aqueous solutions, heparin quenching of the complexes was more significant; a linear quenching curve was obtained with [Os(phen)2CO(PPh3)](PF6)2 in the lower concentration range of 1–12 μg/mL. The interaction of these complexes with heparin in the solutions is discussed. The complexes are shown to be successful in the fast and sensitive detection of heparin in commercial injectable samples. Yixi Xie, Yu Lei, Shalini Shah, Hao Wu, Jian Wu, Elise Megehee, and Enju Wang Copyright © 2013 Yixi Xie et al. All rights reserved. Utilization of N-Bromosuccinimide as a Brominating Agent for the Determination of Sumatriptan Succinate in Bulk Drug and Tablets Tue, 09 Jul 2013 13:31:47 +0000 http://www.hindawi.com/journals/ijac/2013/934357/ One titrimetric and two spectrophotometric methods which are simple, sensitive, and economic are described for the determination of sumatriptan succinate (STS) in bulk drug and in tablet dosage form using N-bromosuccinimide (NBS) as a brominating agent. In titrimetry, aqueous solution of STS is treated with a measured excess of NBS in acetic acid medium, and after the bromination of STS is judged to be complete, the unreacted NBS is determined iodometrically (method A). Spectrophotometric methods entail addition of a known excess of NBS in acid medium followed by the determination of residual NBS by its reaction with excess iodide, and the liberated iodine () is either measured at 370 nm (method B) or liberated iodine is reacted with starch followed by the measurement of the blue colored starch-iodine complex at 570 nm (method C). Titrimetric method is applicable over range 1.0–10.0 mg STS (method A), and the reaction stoichiometry is found to be 1 : 3 (STS : NBS). The spectrophotometric methods obey Beer’s law for concentration range 0.6–15.0 μg mL−1 (method B) and 0.2–4.0 μg mL−1 (method C). The calculated apparent molar absorptivity values were found to be 2.10 × 104 and 7.44 × 104 L mol−1 cm−1, for method B and method C, respectively. Kudige N. Prashanth, Kanakapura Basavaiah, and Madihalli S. Raghu Copyright © 2013 Kudige N. Prashanth et al. All rights reserved. Determination of Tetracycline in Pharmaceutical Preparation by Molecular and Atomic Absorption Spectrophotometry and High Performance Liquid Chromatography via Complex Formation with Au(III) and Hg(II) Ions in Solutions 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. Natural Radioactivity in Soil and Water from Likuyu Village in the Neighborhood of Mkuju Uranium Deposit 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. Monitoring of Heavy Metals Content in Soil Collected from City Centre and Industrial Areas of Misurata, Libya 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. Two Validated Spectrofluorometric Methods for Determination of Gemifloxacin Mesylate in Tablets and Human Plasma 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. Application of Dispersive Liquid-Liquid Microextraction with Graphite Furnace Atomic Absorption Spectrometry for Determination of Trace Amounts of Zinc in Water Samples 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. Isolation and Partial Characterization of Bioactive Fucoxanthin from Himanthalia elongata Brown Seaweed: A TLC-Based Approach 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. Determination of Mercury in Ayurvedic Dietary Supplements That Are Not Rasa Shastra Using the Hydra-C Direct Mercury Analyzer 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. Chemometric Characterization of Alembic and Industrial Sugar Cane Spirits from Cape Verde and Ceará, Brazil 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. An Optimized Adsorbent Sampling Combined to Thermal Desorption GC-MS Method for Trimethylsilanol in Industrial Environments 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. Fundamentals and Applications of Analytical Chemistry in Natural Products 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. Live Cells as Dynamic Laboratories: Time Lapse Raman Spectral Microscopy of Nanoparticles with Both IgE Targeting and pH-Sensing Functions 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. Rapid Screening for Flavone C-Glycosides in the Leaves of Different Species of Bamboo and Simultaneous Quantitation of Four Marker Compounds by HPLC-UV/DAD 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. Erratum to “Potentiometric Determination of Ketotifen Fumarate in Pharmaceutical Preparations and Urine Using Carbon Paste and PVC Membrane Selective Electrodes” 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. Ultra High-Mass Resolution Paper Spray by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry 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. Tin Content Determination in Canned Fruits and Vegetables by Hydride Generation Inductively Coupled Plasma Optical Emission Spectrometry 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. Direct Electron Transfer of Hemoglobin on Manganese III Oxide-Ag Nanofibers Modified Glassy Carbon Electrode 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. Application of CZE Method in Routine Analysis for Determination of B-Complex Vitamins in Pharmaceutical and Veterinary Preparations 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.