ISRN Analytical Chemistry http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Redox-Reaction Based Spectrophotometric Assay of Isoniazid in Pharmaceuticals Tue, 22 Apr 2014 00:00:00 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/717019/ Two spectrophotometric methods are described for the determination of isoniazid (INH) in pharmaceuticals. In the first method (FCR method), INH is reacted with Folin-Ciocalteu reagent in Na2CO3 medium and the resulting blue colored chromogen measured at 760 nm. Iron(II), formed as a result of reaction between INH and iron(III), is made to react with ferricyanide, and the resulting Prussian blue is measured at 760 nm, basing the second method (FFC method). The conditions for better performance are optimized. Beer’s law is obeyed in the concentration ranges 0.5–10 and 0.2–3.0 μg mL−1 for FCR method and FFC methods, respectively, with corresponding molar absorptivity values of and  L mol−1 cm−1. The methods are validated for accuracy, precision, LOD, LOQ, robustness, and ruggedness as per the current ICH guidelines. The validated methods were successfully applied to quantify INH in its commercial formulation with satisfactory results; hence the methods are suitable for isoniazid determination in bulk drugs and pharmaceuticals. N. Swamy, K. N. Prashanth, and K. Basavaiah Copyright © 2014 N. Swamy et al. All rights reserved. Determination of Phenol and Chlorophenols at Single-Wall Carbon Nanotubes/Poly(3,4-ethylenedioxythiophene) Modified Glassy Carbon Electrode Using Flow Injection Amperometry Wed, 16 Apr 2014 17:24:36 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/926213/ Phenol and chlorophenols were investigated using single-wall carbon nanotubes (SWCNT) and poly(3,4-ethylenedioxythiophene) (PEDOT) composite modified glassy carbon electrode (SWCNT/PEDOT/GCE) as a detector in flow injection system. Optimization of experimental variables such as the detection potential, flow rate, and pH of the carrier solution (0.1 M sodium acetate) for the determination of phenol (P), 4-chlorophenol (CP), 2,4-dichlorophenol (DCP), 2,4,6-trichlorophenol (TCP), and pentachlorophenol (PCP) were performed. Under these conditions, analytical parameters were calculated from the calibration curve of measured amperometric responses as a function of concentrations of phenol and chlorophenols. The designed electrode exhibited very good analytical performance. The designed electrode was tested with 20 repetitive injections of each analyte and showed good operational stability. The analytical performance of the SWCNT/PEDOT/GCE electrode under flow through conditions was tested and was found to be impressive. The electrode showed a wider dynamic range for the detection of phenol and chlorophenols with low limits of detection compared with other enzymatic and nonenzymatic sensors. These results suggest that the method is quite useful for the analysis and monitoring of phenols and chlorophenols. Negussie Negash, Hailemichael Alemu, and Merid Tessema Copyright © 2014 Negussie Negash et al. All rights reserved. Analytical Method Development and Validation of Solifenacin in Pharmaceutical Dosage Forms by RP-HPLC Wed, 16 Apr 2014 09:21:50 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/132020/ A new, accurate, precise, and robust HPLC method was developed and validated for the determination of solifenacin in tablet dosage form. The chromatographic separation was achieved on an Inertsil ODS 3V C18 (150 mm × 4.6 mm, 5 μm) stationary phase maintained at ambient temperature with a mobile phase combination of monobasic potassium phosphate (pH 3.5) containing 0.1% triethylamine and methanol (gradient mode) at a flow rate of 1.5 mL/min, and the detection was carried out by using UV detector at 220 nm. The performance of the method was validated according to the present ICH guidelines. Rihana Parveen Shaik, Srinivasa Babu Puttagunta, Chandrasekar Kothapalli Bannoth, and Bala Sekhara Reddy Challa Copyright © 2014 Rihana Parveen Shaik et al. All rights reserved. Isocratic High-Performance Liquid Chromatographic Assay of Olanzapine: Method Development and Validation Thu, 03 Apr 2014 06:34:47 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/616941/ An accurate, precise, sensitive, and rapid isocratic reversed phase high-performance liquid chromatographic (RP-HPLC) method for the analysis of olanzapine (OLP) in bulk drug and in tablets has been developed and validated. Analysis was performed on a 150 mm × 4.6 mm, 5 μm particle Intersil ODS 3V column with 10 mM disodium hydrogen phosphate buffer (pH 7.4)-acetonitrile (35 : 65) (v/v) as mobile phase at a flow rate of 1.0 mL min−1 with UV detection at 254 nm; the constant column temperature was 40°C. The runtime under these chromatographic conditions was less than 8 min. The calibration plot was linear over the concentration range of 2.5–20.0 μg mL−1 with limits of detection and quantification values of 50 and 200 ng mL−1, respectively. The precision and accuracy of the method were assessed by determination of validation data for precision (intraday RSD values of 0.11–0.28%, interday RSD values of 0.15–0.46%), accuracy (0.87–2.80% intraday, 0.33–1.80% interday), and specificity, in accordance with the ICH guidelines. The stability of standard solution and tablet extract was also studied over a period of 24 h. The method was applied for the determination of OLP in tablets with satisfactory results. K. Basavaiah, N. Rajendraprasad, and K. B. Vinay Copyright © 2014 K. Basavaiah et al. All rights reserved. Electrooxidation of Indomethacin at Multiwalled Carbon Nanotubes-Modified GCE and Its Determination in Pharmaceutical Dosage Form and Human Biological Fluids Sun, 30 Mar 2014 12:37:18 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/816012/ A simple, rapid, selective, and sensitive electrochemical method for the direct determination of indomethacin was developed. The electrochemical behavior of indomethacin was carried at multiwalled carbon nanotube- (MWCNTs-) modified glassy carbon electrode (GCE). The cyclic voltammetric results indicated that MWCNT-modified glassy carbon electrode remarkably enhanced electrocatalytic activity towards the oxidation of indomethacin in slightly acidic solutions. It led to a considerable improvement of the anodic peak current for indomethacin and could effectively accumulate at this electrode and produce two anodic peaks at 0.720 V and 0.991 V, respectively, and one reduction peak at 0.183 V. The electrocatalytic behavior was further exploited as a sensitive detection scheme for the determination of indomethacin by differential-pulse voltammetry (DPV). Under optimized conditions, the concentration range and detection limit were 0.2 to 6.0 M and 13.2 nM, respectively. The proposed method was successfully applied to determination of Indomethacine in pharmaceutical samples. The analytical performance of this sensor has been evaluated for detection of analyte in human serum and urine as real samples. Sanjeevaraddi R. Sataraddi, Shreekant M. Patil, Atmanand M. Bagoji, Vijay P. Pattar, and Sharanappa T. Nandibewoor Copyright © 2014 Sanjeevaraddi R. Sataraddi et al. All rights reserved. Development and Validation of High Performance Liquid Chromatography Method for Simultaneous Estimation of Flavonoid Glycosides in Withania somnifera Aerial Parts Mon, 10 Mar 2014 08:57:16 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/351547/ Withania somnifera (L.) Dunal (Solanaceae) commonly known as ashwagandha, is an important plant in Ayurveda and is believed to increase longevity and vitality. The root is considered to be the medicinally important part of the plant as per classical texts and accordingly is the subject of most Pharmacopeial monographs. The aerial parts, being less expensive, are sometimes mixed with roots to prepare “standardized” extracts of W. somnifera, and in cases with false declaration of plant part used as roots on the certificate of analysis. The present study described a new, simple, accurate, and precise HPLC method for the simultaneous determination of flavonoid glycosides as unique constituents of the aerial parts, being absent in roots of the plant. The RSD for intra- and interday analyses was less than 2.5% and the recovery was 90–108%. The method was used to analyze samples of roots and aerial parts of the plant collected from India and Egypt. The samples of commercially available extracts of W. somnifera were also analyzed and many samples were found to contain flavonoid glycosides indicating a possible undeclared use of aerial parts in the extracts derived from roots in commercial practice. Deepak Mundkinajeddu, Laxman P. Sawant, Rojison Koshy, Praneetha Akunuri, Vineet Kumar Singh, Anand Mayachari, Maged H. M. Sharaf, Murali Balasubramanian, and Amit Agarwal Copyright © 2014 Deepak Mundkinajeddu et al. All rights reserved. Simultaneous Estimation of Ambroxol Hydrochloride and Cetirizine Hydrochloride in Pharmaceutical Tablet Dosage Form by Simultaneous Equation Spectrophotometric Method: A Quality Control Tool for Dissolution Studies Tue, 04 Mar 2014 07:17:15 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/236570/ Ambroxol Hydrochloride and Cetirizine Hydrochloride are used for the treatment of bronchitis, cough, and allergy. A simple, economical, accurate, and precise method for simultaneous estimation of Ambroxol Hydrochloride and Cetirizine Hydrochloride in tablet dosage form has been developed. Simultaneous equation method based on measurement of absorbance at two wavelengths, that is, 244 nm and 230 nm, of Ambroxol Hydrochloride and Cetirizine Hydrochloride in pH 6.8 phosphate buffer. Both of these drugs obeyed Beer-Lambert’s law in the concentration range of 2–18 µg/mL for Ambroxol Hydrochloride and 2–20 µg/mL for Cetirizine Hydrochloride. The high values of correlation coefficient () indicated good linearity of calibration curve for both the drugs. The accuracy and precision of method were determined and the method was validated statistically. Result of percentage recovery study confirms the accuracy of proposed method. As per the ICH guidelines, the method validation parameters checked were linearity, accuracy, precision, and assay of drug formulation. Based on the results obtained, it can be concluded that the proposed simultaneous equation spectrophotometric method for simultaneous estimation of Ambroxol Hydrochloride and Cetirizine Hydrochloride is rapid, economical, accurate, precise, and reproducible. Hence, the proposed method can be employed for quantitative estimation of Ambroxol Hydrochloride and Cetirizine Hydrochloride from their tablet dosage form. Deepak Sharma, Mankaran Singh, Dinesh Kumar, and Gurmeet Singh Copyright © 2014 Deepak Sharma et al. All rights reserved. Characterization of Cr-Curcumin Complex by Differential Pulse Voltammetry and UV-Vis Spectrophotometry Tue, 04 Mar 2014 06:39:33 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/372576/ Differential Pulse Voltammetry (DPV) and UV-Vis techniques were used in characterizing the complexation of chromium with curcumin. It was observed that chromium complexed with curcumin in a 1 : 3 ratio. The experimental values that were used to calculate this ratio were independently determined by the two techniques used. The values obtained from each technique agree with each other reasonably well, within limits of experimental error. The stability constant or formation constant, , of the complex, , was determined using the Lingane equation and Gibb’s free energy of formation was calculated as −58.18 kJ. Maurice O. Iwunze Copyright © 2014 Maurice O. Iwunze. All rights reserved. Removal of Hardness of Earth Alkaline Metals from Aqueous Solutions by Ion Exchange Method Sun, 23 Feb 2014 00:00:00 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/621794/ An ion exchange process was introduced as an approach for softening of artificial hard water solutions. A strong acid cation exchange resin, Amberlite IR 120 [Na+], was used to reduce the hardness of water with the matrix of styrene-divinylbenzene copolymer having functional group as sulfonate. The ion exchange behavior of the ions of calcium and magnesium in synthetic solutions of hard water was investigated with the variables depending on pH, stirrer speed of the solutions and amount of the resin as a function of contact time between resin phase and hard water solution. The maximum ion exchange capacity was found to be 68 mg/g for Ca(II) and 12 mg/g for Mg(II) at pH 3.0. The method is a simple and efficient one to remove calcium and magnesium hardness from hard water solutions with the resin having more selectivity for calcium. Gulten Cetin Copyright © 2014 Gulten Cetin. All rights reserved. Comparative Phytochemical Analyses of Resins of Boswellia Species (B. papyrifera (Del.) Hochst., B. neglecta S. Moore, and B. rivae Engl.) from Northwestern, Southern, and Southeastern Ethiopia Thu, 13 Feb 2014 08:40:44 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/374678/ Oleogum resins of B. papyrifera, B. neglecta, and B. rivae were collected from northwestern, southern, and southeastern Ethiopia, and their respective methanol extracts and essential oils were extracted and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The investigation on essential oils led to the identification of 6, 7, and 8 constituents for B. papyrifera, B. neglecta, and B. rivae, respectively. The essential oil of B. papyrifera is mainly characterized by the presence of octyl acetate (57.1–65.7%) and n-octanol (3.4–8.8%). B. neglecta is rich in α-pinene (32.6–50.7%) followed by terpinen-4-ol (17.5–29.9%) and α-thujene (12.7–16.5%), whereas B. rivae was predominated by α-pinene (32.5–66.2%) followed by p-cymene (5.7–21.1%) and limonene (1.1–19.6%). Methanol extracts of the three Boswellia species were found to consist of diterpines (incensole, incensyl acetate and verticilla-4(20),7,11-triene), triterpenes (β-amyrin, α-amyrin, β-amyrenone, and α-amyrenone), nortriterpenes (24-noroleana-3,12-diene and 24-norursa-3,12-diene), and α-boswellic acid. The investigation on the methanol extract showed that only B. papyrifera contains diterpenes and nortriterpenes, whereas B. rivae and B. neglecta consist of only triterpenes. The results indicate that the three Boswellia species were characterized by some terpenes and these terpenoic constituents could be recognized as chemotaxonomical markers for each species. Deribachew Bekana, Tesfahun Kebede, Mulugeta Assefa, and Habtemariam Kassa Copyright © 2014 Deribachew Bekana et al. All rights reserved. Complex Formation of Nickel(II) and Copper(II) with Barbituric Acid Wed, 12 Feb 2014 07:58:03 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/243175/ Equilibrium studies have been carried out on complex formation of M2+ ions (M = Ni and Cu) with L = barbituric acid (BA) in aqueous solution at °C and with an ionic strength of  M (KNO3) in aqueous medium. The basicity of the ligand was also assessed by the determination of the dissociation constants of the ligand. The experimental pH titration data were analyzed with the help of the BEST computer program in order to evaluate the stability constants of the various species formed. The stability constants of the binary systems decrease in the order of Cu(II) > Ni(II). Distribution diagrams for the species were drawn showing the concentrations of individual species as a function of pH by the SPE software program. Naciye Türkel and M. Suat Aksoy Copyright © 2014 Naciye Türkel and M. Suat Aksoy. All rights reserved. Ginsenosides in Commercial Ginseng Products Analyzed by Liquid Chromatography-Tandem Mass Spectrometry Mon, 10 Feb 2014 14:48:31 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/486842/ Although the LC/MS-MS method has been developed to analyze ginsenosides in ginseng roots, this method has not yet been utilized to quantify ginsenosides in ginseng products. In this paper, an internal standard method by LC/MS-MS was developed to analyze the ginsenosides content in the commercial ginseng products such as the ginseng capsules. We compare the standard addition method and the internal standard methods for the quantification of several ginsenosides (e.g., Rb1, Rb2, Rb3, Rc, Rd, Re, Rg1, and Rg3) in five commercial ginseng capsules. The results showed that the internal standard method is as good as the standard addition method and is a less tedious approach. Linda Uhr, Yuchun Chen, Daniel Sit, and Paul C. H. Li Copyright © 2014 Linda Uhr et al. All rights reserved. Altered Metabolic Profile in Congenital Lung Lesions Revealed by 1H Nuclear Magnetic Resonance Spectroscopy Wed, 29 Jan 2014 11:39:08 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/391836/ Congenital lung lesions are highly complex with respect to pathogenesis and treatment. Large-scale analytical methods, like metabolomics, are now available to identify biomarkers of pathological phenotypes and to facilitate clinical management. Nuclear magnetic resonance (NMR) is a unique tool for translational research, as in vitro results can be potentially translated into in vivo magnetic resonance protocols. Three surgical biopsies, from congenital lung malformations, were analyzed in comparison with one control sample. Extracted hydrophilic metabolites were submitted to high resolution 1H NMR spectroscopy and the relative concentration of 12 metabolites was estimated. In addition, two-dimensional NMR measurements were performed to complement the results obtained from standard monodimensional experiments. This is one of the first reports of in vitro metabolic profiling of congenital lung malformation. Preliminary data on a small set of samples highlights some altered metabolic ratios, dealing with the glucose conversion to lactate, to the relative concentration of phosphatidylcholine precursors, and to the presence of myoinositol. Interestingly some relations between congenital lung lesions and cancer metabolic alterations are found. Maria Chiara Mimmi, Maurizio Ballico, Ghassan Nakib, Valeria Calcaterra, Jose Louis Peiro, Mario Marotta, and Gloria Pelizzo Copyright © 2014 Maria Chiara Mimmi et al. All rights reserved. Nonconjugated Polyelectrolyte as Efficient Fluorescence Quencher and Their Applications as Biosensors: Polymer-Polymer Interaction Wed, 22 Jan 2014 14:08:41 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2014/841857/ A simple fluorescence quenching method for the quantitation in serum of an acute phase reactant, C-reactive protein (CRP), which can differentiate between viral and bacterial infections, is described, where material and reagent costs are minimal. The study harnesses a fluorescence quenching between a nonfluorescent polyelectrolyte containing a ligand (O-phosphorylethanolamine, PEA) and fluorophore (fluorescamine isomer 1) containing polyelectrolyte. The quenching was attributed due to strong polymer-polymer interaction through intermolecular hydrogen bonding. The nonlinear behaviour of Stern-Volmer plot indicates a binding induced quenching, that is, static quenching. However, fluorescence was found to increase in presence of C-reactive protein, due to the specific molecular recognition occurring between CRP and PEA, thereby excluding fluorophore containing chain. A definite correlation was found between concentration of CRP and fluorescence intensity and the method exhibited a linear relationship in the range of 40–360 ng/mL with a detection limit of 30 ± 2 ng/mL. The antibody free method was successfully applied for the analysis of CRP in human serum samples and the method showed good correlation with hospital measurements . Thus the fluorescence based polyelectrolyte biosensor is a potential system for rapid, and antibody free platform for CRP detection. Vidya Raj and Sreenivasan Kunnetheeri Copyright © 2014 Vidya Raj and Sreenivasan Kunnetheeri. All rights reserved. Capillary Electrophoresis with UV Detection to Determine Cocaine on Circulated Banknotes Thu, 19 Dec 2013 18:03:29 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/489705/ A new methodology employing capillary electrophoresis with UV detection (CE-UV) was developed, validated, and applied to determine the presence of cocaine on Brazilian banknotes. Some of the banknotes analyzed were obtained directly from general circulation (well used) while others were collected from Automated Teller Machines (ATMs) (relatively new). The background electrolyte optimized using Peakmaster 5.1 software was composed of 60 mmol L−1 TRIS(hydroxymethyl)aminomethane and 20 mmol L−1 2-hydroxyisobutyric acid, at pH 8.4. The separation time achieved for cocaine was only 2.5 minutes. The figures of merit obtained in the evaluation of the proposed method were good linearity () in the concentration range of 0.8–8.0 mg L−1 and acceptable limits of detection and quantification (0.2 mg L−1 and 0.8 mg L−1, resp.). The relative standard deviations of the instrumental precision, repeatability (intraday), and intermediate precision (interday) were less than 4.5% (peak area). The accuracy evaluated through comparing the cocaine results for the banknotes determined by the proposed CE-UV method and using an LC-MS/MS method showed no significant difference between the methods (95% confidence level). In the analysis of the samples cocaine was detected on 93% of the circulating banknotes in amounts ranging from 11.5 μg to 2761.9 μg per note. Melina Heller, Luciano Vitali, Mariana A. Siqueira, Alysson V. F. Sako, Marcel Piovezan, and Gustavo A. Micke Copyright © 2013 Melina Heller et al. All rights reserved. Calculation of the Absorption Cross Sections of Some Molecules from GEISA Database at the Wavelengths of Isotopically Different CO2 Lasers Tue, 26 Nov 2013 09:23:25 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/592971/ A calculation of the absorption cross section of some molecules (NH3, C2H4, CO2, O3, NO2, PH3, HNO3, SF6, CH3OH, HCOOH, OCS, CH3CN, C2H6, SO2, and H2O) at the wavelengths transmitted by a CO2 laser filled with different isotopes (12C16O2, 13C16O2, 12C18O2, 14C16O2, 14C18O2, 13C18O2, and 12C16O18O) is presented. The spectroscopical parameters for the molecules from GEISA database have been used. Hence the selection of the molecules was substantially based on the availability of the parameters in the database. The results of the calculations may be used in designing the differential absorption technique for remote monitoring of these molecules. The pressure and temperature dependence of the cross sections are described by and coefficients; these coefficients were calculated for the largest absorption cross sections for each molecule. The absorption cross sections of CH3OH and HCOOH at low pressures for all these CO2 lasers are also presented. These calculations are provided for design of new CO2-laser-pumped far-infrared lasers. Asylkhan Rakhymzhan and Alexey Chichinin Copyright © 2013 Asylkhan Rakhymzhan and Alexey Chichinin. All rights reserved. Sumac Leaves as a Novel Low-Cost Adsorbent for Removal of Basic Dye from Aqueous Solution Sun, 24 Nov 2013 10:04:23 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/210470/ Sumac Leaves (SL) (Rhus Coriaria L. ) were investigated as an inexpensive and effective adsorbent for the adsorption of methylene blue (MB) from aqueous solution. The effects of initial dye concentration, initial solution pH, phases contact time, and adsorbent dose on the adsorption of MB on SL were investigated. The amount of dye adsorbed was found to vary with initial solution pH, Sumac Leaves dose, MB concentration, and phases contact time. The Langmuir and Freundlich adsorption models were evaluated using the experimental data and the experimental results showed that the Langmuir model fits better than the Freundlich model. The maximum adsorption capacity was found to be 151.69 mg/g from the Langmuir isotherm model at 25°C. The value of the monolayer saturation capacity of SL was comparable to the adsorption capacities of some other adsorbent materials for MB. The adsorption rate data were analyzed according to the pseudo-first order kinetic and pseudo-second order kinetic models and intraparticle diffusion model. It was found that kinetic followed a pseudo-second order model. Öznur Dülger, Fatma Turak, Kadir Turhan, and Mahmure Özgür Copyright © 2013 Öznur Dülger et al. All rights reserved. Stability Indicating HPTLC Method for Analysis of Rifaximin in Pharmaceutical Formulations and an Application to Acidic Degradation Kinetic Study Sun, 10 Nov 2013 08:56:29 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/613218/ A specific stability indicating high-performance thin-layer chromatographic method for analysis of rifaximin both as a bulk drug and in formulations was developed and validated. The method employed HPTLC aluminium plates precoated with silica gel 60 F254 as the stationary phase. The optimized mobile phase system consisted of n-hexane : 2-propanol : acetone : ammonia (5 : 4.1 : 1, v/v/v/v), which gave compact spots for rifaximin at of 0.59 ± 0.03. Rifaximin was subjected to forced degradation studies in order to check the specificity of the method. Densitometric analysis of rifaximin was carried out in the absorbance reflectance mode at 443 nm. The calibration plots showed linear relationship in the concentration range of 400–3200 ng per band. Moreover, linearity was also confirmed by verification of homoscedasticity of variance. According to validation studies, the developed method was repeatable and specific as revealed by % RSD less than 2 and hence can be used for routine analysis of pharmaceutical formulation. Moreover, the method could effectively separate the drug from its degradation products; hence it can be employed as a stability indicating one. The kinetics of acid degradation process at various temperatures was also investigated and first-order rate constant, half-life, shelf life, and activation energy were computed. Kalpana G. Patel, Nitesh R. Jain, and Purvi A. Shah Copyright © 2013 Kalpana G. Patel et al. All rights reserved. Minor Volatile Compounds in White Wines from Canary Islands, Madeira, and Pico (Azores) by Headspace Solid-Phase Microextraction-Gas Chromatography-Mass Spectrometry: A Qualitative Study Thu, 07 Nov 2013 09:53:46 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/529306/ Application of headspace solid-phase microextraction (HS-SPME) coupled with high-resolution gas chromatographic (HRGC) analytical system was studied for detection and identification of volatile compounds in wines. Four different SPME fibers were tested, and 138 different compounds were detected and identified. The best fiber for the determination of different groups of compounds was selected. Using these results, a comparative study of Madeira, Tenerife (Canary Islands), and Pico (Azores) was carried out. S. J. Pérez-Olivero, J. P. Pérez Trujillo, and J. E. Conde Copyright © 2013 S. J. Pérez-Olivero et al. All rights reserved. Pharmaceutical Applications of Chemometric Techniques Wed, 30 Oct 2013 08:24:21 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/795178/ Chemometrics involves application of various statistical methods for drawing vital information from various manufacturing-related processes. Multiway chemometric models like parallel factor analysis (PARAFAC), Tucker-3, N-partial least square (N-PLS), and bilinear models like principle component regression (PCR) and partial least squares (PLS) have been discussed in the paper. Chemometric approaches can be used to analyze the data obtained from various instruments including near infrared (NIR), attenuated total reflectance Fourier transform infrared (ATR-FTIR), high-performance liquid chromatography (HPLC), and terahertz pulse spectroscopy. The technique has been used in the quality assurance and quality control of pharmaceutical solid dosage forms. Moreover, application of chemometric methods in the evaluation of properties of pharmaceutical powders and tablet parametric tests has also been discussed in the review. It has been suggested as a useful method for the real-time in-process testing and is a valuable process analytical tool. Inderbir Singh, Prateek Juneja, Birender Kaur, and Pradeep Kumar Copyright © 2013 Inderbir Singh et al. All rights reserved. An Approach of Laser-Induced Breakdown Spectroscopy to Detect Toxic Metals in Crushed Ice Ball Mon, 21 Oct 2013 10:17:46 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/719483/ This paper deals the application of laser-induced breakdown spectroscopy (LIBS) to toxic metals used as pigment in crushed ice-ball samples. The present work highlights the advantages of LIBS as in situ, real-time analytical tool for rapid detection of toxic or heavy metals like lead (Pb) and chromium (Cr) and non toxic elements like carbon (C), nitrogen (N), magnesium (Mg), calcium (Ca), sodium (Na), and potassium (K) in crushed ice-ball of different colors (red, green, yellow, pale yellow, and orange) collected from five different areas, with minimal sample preparation. For rapid surveillance of toxic metals we have used multivariate analysis, that is, principal component analysis (PCA) with the LIBS spectral data of ice-ball samples. This study suggests that LIBS coupled with PCA may be an instant diagnostic tool for identification and classification of adulterated and nonadulterated samples. Rahul Agrawal, Ashok Kumar Pathak, Awadhesh Kumar Rai, and Gyanendra Kumar Rai Copyright © 2013 Rahul Agrawal et al. All rights reserved. Electronic Structure of 2H-Tetraphenylporphyrin at Fe/Si (100) Interface Mon, 30 Sep 2013 11:11:49 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/637219/ Many recent studies have highlighted the possibility to tailor the physical and chemical properties of porphyrin at the molecular level to design novel catalysts, sensors and devices with applications in electronics, opto-electronics, and so forth. In the present work, we study the electronic properties of 2H-Tetraphenylporphyrin (2H-TPP) on iron (Fe) and iron silicide (Fe3Si) onto Si (100) substrate using X-ray and Ultraviolet photoelectron spectroscopy (XPS & UPS). The results revealed that the iron atom is coordinated by TPP molecules on Fe/Si as well as on Fe3Si/Si. XPS results provide evidence of the iron coordination with TPP molecules. The UPS analysis evidenced the fine structure in the electronic spectra related to HOMO states below the Fermi level. Chhagan Lal and I. P. Jain Copyright © 2013 Chhagan Lal and I. P. Jain. All rights reserved. Removal of Antimony(III) from Aqueous Solution by Using Grey and Red Erzurum Clay and Application to the Gediz River Sample Mon, 30 Sep 2013 08:48:30 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/962781/ The removal of Sb(III) from waste water is achieved in batch system by using grey and red Erzurum (Oltu) clay which are cheap and natural adsorbents. Adsorption experiments were studied. For this purpose, various important parameters such as contact time, pH, and temperature were examined on the adsorption of Sb(III) ions onto grey and red Erzurum (Oltu) clay. Decreasing amount of Sb(III) ions in the solutions by adsorption was determined with differential pulse anodic stripping voltammetry (DPASV) method. Langmuir and Freundlich isotherms for the adsorption processes were drawn. The adsorption was demonstrated in similarity with Langmuir model. The maximum adsorption capacity of red Erzurum clay for Sb(III) was found to be 9.15 mg/g. Also, surface of the adsorbent was characterized by using FTIR spectroscopy. Red Erzurum clay was applied on real sample (Gediz River), and 72.6% adsorption was obtained. Şerif Targan, Vedia Nüket Tirtom, and Birsen Akkuş Copyright © 2013 Şerif Targan et al. All rights reserved. Development and Validation of a Simple and Sensitive Spectrometric Method for Estimation of Cisplatin Hydrochloride in Tablet Dosage Forms: Application to Dissolution Studies Thu, 19 Sep 2013 09:56:33 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/936254/ Cisplatin hydrochloride is an important chemotherapeutic drug for cancer treatment. It has a low molar absorptivity in the UV region and has no fluorescence. Therefore, a selective derivatizing reaction is required for its detection in bulk and pharmaceutical dosage form if detection by UV spectrophotometry is sought. In view of this, a simple, accurate, rapid, and cost-effective spectrophotometric method for its estimation has been developed by the complexation of the drug with ortho-phenylene diamine and monitoring the absorbance of formed green color at 706 nm. The method has been validated and successfully applied for the assay and dissolution studies of cisplatin hydrochloride tablets. The method demonstrated good linearity over the range from 0.4 to 1.4 μg/mL with a correlation coefficient of 0.9999. The accuracy of the method was 99.98%. The precision demonstrated relative standard deviation of less than 2.5%. The developed method was successfully applied for dissolution studies of sustained release tablets of cisplatin with a cumulative release of 86.7% in 12 hours. The proposed method can be applied in routine quality control in the pharmaceutical industries since it is precise, accurate, simple, and economic. Mohit Basotra, Sachin Kumar Singh, and Monica Gulati Copyright © 2013 Mohit Basotra et al. All rights reserved. Method Development and Validation for Estimation of Eperisone Hydrochloride as API and in Tablet Dosage Form by Two Spectroscopic Methods Wed, 18 Sep 2013 13:04:56 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/534763/ Two simple and sensitive spectrophotometric methods have been developed for the determination of eperisone hydrochloride based on its ability to be detected in UV region (Normal UV) and its oxidation using potassium permanganate in alkaline medium (kinetic spectroscopic). The detection was done at 261.40 nm and 603.5 nm. The different experimental parameters affecting the method development were studied and optimized. The initial rate and fixed time method were utilized to construct calibration graph, and 5 minutes and 3 minutes, respectively, were found suitable for the determination of the concentration of drug. Linearity was found over the concentration range of 2–20 μg/mL, 15–30 μg/mL, and 15–35 μg/mL by UV, initial rate, and fixed time methods, respectively. The results were validated as per the ICH guidelines. RSD values were found to be less than 2%. The methods were applied for estimation of eperisone hydrochloride in RAPISONE (Abbott, Maharashtra). The assay results were found to be 100.4% ± 0.08, 99.93% ± 0.05, and 99.41% ± 0.04 by UV, initial rate, and fixed time method, respectively. Statistical comparison of the proposed methods showed a good agreement indicating no significant difference in accuracy and precision, thus confirming the suitability of UV and kinetic method for the estimation of eperisone hydrochloride in bulk as well as in tablet dosage forms. Joytosh Banerjee, Renu Solanki, and Badri Prakash Nagori Copyright © 2013 Joytosh Banerjee et al. All rights reserved. Microwave-Assisted Derivatization of Bile Acids for Gas Chromatography/Mass Spectrometry Determination Thu, 05 Sep 2013 18:42:27 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/805678/ Bile acids derived from cholesterol are produced in the liver, and their analysis is difficult due to their complex natures and their low concentrations in biological fluids. Mixtures of various derivatives, created via conventional heating, are used for such analyses. Microwave radiation is proposed to accelerate the derivatization process. This paper presents a mass fragmentation study and microwave-assisted derivatization (MAD) for the silylation of bile acids (cholic and ursodesoxycholic) prior to gas chromatography and mass spectrometry analysis. The derivatization was performed using the two-step process of methoximation and silylation. The reaction time, power, and quantity of N,O-bis-(trimethylsilyl) trifluoroacetamide (BSTFA) + 1% trimethylchlorosilane (TCMS) were optimized to improve the derivatization. The optimized derivatization conditions required 210 W for 3 min. The MAD method exhibited linearity with respect to cholic acid between 0.78 and 20.0 μg mL−1 with an LOQ of 0.23 μg mL−1 and a precision ranging from 1.08% to 9.32% CV. This optimized derivatization method is valid for the analysis of bile acids in different matrices. Maria José Nunes de Paiva, Helvécio Costa Menezes, and Zenilda de Lourdes Cardeal Copyright © 2013 Maria José Nunes de Paiva et al. All rights reserved. Effects of Enoant and Ischemia and Reperfusion on Lens Metabolites of Rats Wed, 28 Aug 2013 13:41:09 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/964601/ The effects of the ischemia and reperfusion on the lens metabolites and the effect of a phytotherapeutic commercial product called “Enoant” (mixed polyphenol content) on the selected lens metabolites were investigated. For this aim, 30 Wistar rats were divided into three groups according to their diet and being subjected to ischemia. 10 of the rats as Group I were fed on dry diet; the other 10 (Group II) were fed on dry diet and drinking water with Enoant. At the end of 15 days period, both groups of rats were subjected to ischemia for 2 hours and reperfused. After another 15 days with their same diet, the rats were decapitated. The remaining 10 rats, which were not subjected to ischemia (Group III), were fed on dry diet only. 1HNMR spectroscopy was used for the determination of lens metabolites of each group of rats. The results obtained from the three groups have been compared statistically. The differences of metabolites were significant except pyruvate and succinate. Oral administration of Enoant revealed effects on increasing membrane stabilization, the antioxidant capacity, osmotic regulator molecule capacity, and sorbitol content of lens disturbed by ischemia. Enoant can be used where oxidative or osmotic stress is formed. Hülya Güngel, Asiye Nurten, İhsan Kara, Serife Evrim Kepekci Tekkeli, Elif Özkök, and Burçin Yıldız Copyright © 2013 Hülya Güngel et al. All rights reserved. RP-HPLC Method Development and Validation for Simultaneous Estimation of Clarithromycin and Paracetamol Wed, 21 Aug 2013 12:00:38 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/948547/ The present work describes a simple, rapid, and reproducible reverse phase high performance liquid chromatography (RP-HPLC) method for the simultaneous estimation of clarithromycin (CLA) and paracetamol (PCM). C18 column (Kromasil ODS, 5 µm, 250 × 4.6 mm) and a mobile phase containing phosphate buffer (0.05 M) along with 1-octane sulphonic acid sodium salt monohydrate (0.005 M) adjusted to pH 3.2: acetonitrile (50 : 50 v/v) mixture was used for the separation and quantification. The flow rate was 1.0 mL/min and the eluents were detected by UV detector at 205 nm. The retention times were found to be 2.21 and 3.73 mins, respectively. The developed method was validated according to ICH guidelines Q2 (R1) and found to be linear within the range of 75–175 µg/mL for both drugs. The developed method was applied successfully for assay of clarithromycin and paracetamol in their combined in-house developed dosage forms and in vitro dissolution studies. Sadana Gangishetty and Surajpal Verma Copyright © 2013 Sadana Gangishetty and Surajpal Verma. All rights reserved. Development and Validation of a Stability Indicating RP-UPLC Method for Analysis of Imipramine Hydrochloride in Pharmaceuticals Wed, 21 Aug 2013 11:18:06 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/913765/ The objective of the current study was the development of a simple, rapid, and accurate isocratic reverse-phase ultra-performance liquid chromatographic (RP-UPLC) method for the routine control analysis of imipramine hydrochloride (IMH) in bulk drug and in pharmaceutical formulations. This work was carried out in order to reduce analysis time and maintaining good efficiency which in turn is focused on high-speed chromatographic separations. The method was developed using Waters Acquity BEH C18 column (100 mm × 2.1 mm, 1.7 μm) with mobile phase consisting of a mixture of acetonitrile and ammonium acetate buffer of pH-5 (80 : 20, v/v/v). UV detection was performed at 220 nm for eluted compound. An excellent linearity was observed in the concentration range 0.2–3 µg/mL IMH with a regression coefficient () value of 0.9999. The method developed was validated and forced degradation was performed as per ICH guidelines. The limit of detection () was 0.2532 ng/mL and the limit of quantitation () was found to be 0.7672 ng/mL. The drug IMH was subjected to hydrolytic, acidic, basic, thermal, photolytic, and oxidative stress conditions according to ICH regulations. IMH was found to be stable in basic, thermal, and photolytic conditions and degrades in acidic, hydrolytic, and oxidative stress conditions. H. N. Deepakumari, K. B. Vinay, and H. D. Revanasiddappa Copyright © 2013 H. N. Deepakumari et al. All rights reserved. Spectrophotometric Determination of Bromhexine HCl in Pure and Pharmaceutical Forms Mon, 12 Aug 2013 18:15:03 +0000 http://www.hindawi.com/journals/isrn.analytical.chemistry/2013/861851/ Five spectrophotometric methods for determination of bromhexine HCl have been developed, validated, and applied for the assay of the drug in pharmaceuticals. Methods A, B, and C are based on ion-pair complexation of drug, in acidic buffers, with triphenylmethane dyes, namely, bromothymol blue (BTB), bromophenol blue (BPB), and bromocresol green (BCG). The complexes are extracted into chloroform, and absorbance is measured at around 415 nm as function of concentration of the drug. The stoichiometry of the complex is found to be 1 : 1 in each case. Method D depends upon charge-transfer complexation of neutralized drug with iodine which produces iodide ion whose absorbance at 366 nm is measured as function of concentration of the drug. This complex too has 1 : 1 composition as determined by Job’s method. Method E is developed on the basis of oxidation of the drug with alkaline KMnO4 which generates green-colored manganate ion with 610 nm. As the intensity of green color increased with increasing time kinetics of the reaction is followed, and calibration curves are constructed by using initial rate and fixed time methods. Excellent recovery studies with high accuracy and precision indicate that the methods can be successfully used in industries for the assay of drug in pure form and pharmaceuticals. K. Susmitha, M. Thirumalachary, and G. Venkateshwarlu Copyright © 2013 K. Susmitha et al. All rights reserved.