ISRN Spectroscopy The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Simultaneous Estimation of Paracetamol, Ambroxol Hydrochloride, Levocetirizine Dihydrochloride, and Phenylephrine Hydrochloride in Combined Tablet Formulation by First-Order Derivative Spectrophotometry Sun, 30 Mar 2014 10:01:19 +0000 Paracetamol, ambroxol hydrochloride, levocetirizine dihydrochloride, and phenylephrine hydrochloride are used in combination for the treatment of chronic sinusitis, rhinitis, fever, nasal discharge, sore throat, and wheezing. The present work deals with method development for simultaneous estimation of paracetamol, ambroxol hydrochloride, levocetirizine dihydrochloride, and phenylephrine hydrochloride in tablet formulation by first-order derivative spectrosphotometry. For determination of sampling wavelength, 10 μg/mL of each of paracetamol, ambroxol hydrochloride, levocetirizine dihydrochloride, and phenylephrine hydrochloride was scanned in 200–400 nm ranges and sampling wavelengths were found to be 305.5 nm for paracetamol, 321 nm for ambroxol hydrochloride, 244 nm for levocetirizine dihydrochloride, and 280 nm for phenylephrine hydrochloride in first-order derivative spectrophotometry. In this method, linearity was observed in the ranges of 20–140 μg/mL for paracetamol and 10–70 μg/mL for ambroxol hydrochloride, levocetirizine dihydrochloride, and phenylephrine hydrochloride. The % recovery was within the range between 98 and 102%, and % relative standard deviation for precision and accuracy of the method was found to be less than 2%. The method is validated as per International Conference on Harmonization Guidelines. The method can be successfully applied for the simultaneous analysis of these drugs in pharmaceutical dosage forms. K. Anandakumar and P. Veerasundari Copyright © 2014 K. Anandakumar and P. Veerasundari. All rights reserved. Extractive Spectrophotometric Determination of Tenofovir Disoproxil Fumarate Using Acidic Triphenylmethane Dyes Wed, 12 Mar 2014 08:25:16 +0000 Tenofovir disoproxil fumarate is a nucleotide reverse transcriptase inhibitor that has activity against the hepatitis B and HIV viruses. Three simple and sensitive extractive spectrophotometric methods have been described for the assay of tenofovir disoproxil fumarate either in pure form or in pharmaceutical formulations. The developed methods involve formation of colored chloroform extractable ion-pair complexes of the drugs with triphenylmethane dyes, namely, bromothymol blue (BTB), bromophenol blue (BPB), and bromocresol purple (BCP) in acidic medium. The extracted complexes showed absorbance maxima between 410 and 415 nm. Beer’s law is obeyed in the concentration ranges 1.5–25, 1.0–25, and 1.25–25 μg mL−1 with BTB, BPB, and BCP, respectively. The effectc of concentration of dye, pH, and interference of excipients have been studied and optimized. The limits of detection and quantification have been determined. All three methods are validated as per the guidelines of ICH. The methods have been applied to the determination of drug in commercial tablets and results of analysis were validated statistically through recovery studies. K. Susmitha, M. Thirumalachary, T. Charan Singh, and G. Venkateshwarlu Copyright © 2014 K. Susmitha et al. All rights reserved. Novel Spectrophotometric Methods for the Determination of Selegiline Hydrochloride in Bulk and Its Pharmaceutical Preparation Sun, 23 Feb 2014 09:39:53 +0000 A simple and highly selective spectrophotometric method has been developed for the determination of selegiline hydrochloride in bulk and formulations. Method A is based on the oxidation of 3-methyl-2-benzothiazolinone hydrazone in the presence of ceric ammonium sulphate, followed by its coupling reaction with drug to form a colored product having of 629 nm. Method B is based on the coupling reaction of drug with 4-aminoantipyrine to give a new ligand that reacts with copper(II) to give intense bluish red colored chelate which is measured at 539 nm. Beer’s law is obeyed in the range of 10.00–85.00 μg mL−1 with molar absorptivity of for method A and 20.00–120.00 μg mL−1 with molar absorptivity of for method B. The optimum reaction condition and the analytical parameters are evaluated. The results obtained indicate that the methods are free from interference of the ingredients; thus they are successfully applied to pharmaceutical formulations. Kumble Divya and Badiadka Narayana Copyright © 2014 Kumble Divya and Badiadka Narayana. All rights reserved. Fluorescence Spectroscopy Study on the Interaction of Acetal Cleavable Anionic Surfactants and Bovine Serum Albumin Mon, 17 Feb 2014 17:19:22 +0000 The interactions between bovine serum albumin (BSA) and two cleavable anionic surfactants, sodium 3-[(2-nonyl-1,3-dioxolan-4-yl)methoxy]propane-1-sulfonate (SNPS) and sodium 3,3′-(2-nonyl-1,3-dioxane-5,5-diyl)bis(methylene)bis(oxy)dipropane-1-sulfonate (SNDPS), have been studied by means of fluorescence spectroscopy and thermodynamic analysis. The fluorescence of BSA is quenched via a static quenching mechanism with the addition of the surfactants. The binding constants of the surfactants and proteins have been measured, with (SNPS) = M−1 and (SNDPS) = 7.08 × 104 M−1, respectively. The interaction between surfactants and BSA is mainly of hydrophobic nature, based on the number of binding sites, n[n(SNPS) = 1.57, n(SNDPS) = 1.47], and the thermodynamic relationship. These results suggest that SNPS and SNDPS could be effective protein denaturants for protein separation and analysis. Xin Zhang, Jianhong Bian, Wenjie Zhai, Jing Dong, Huihui Liang, and Zhao Zhang Copyright © 2014 Xin Zhang et al. All rights reserved. Gamma Emitting Radionuclides in Soils from Selected Areas in Douala-Bassa Zone, Littoral Region of Cameroon Wed, 22 Jan 2014 12:13:28 +0000 A study of natural radioactivity levels in some composites of eighteen soil samples selected within Douala-Bassa zone of Littoral Region has been evaluated. The samples were analysed using gamma spectrometry based broad energy germanium detector (BEGe 6350). The activity profile of radionuclide shows low activity across the studied areas. The obtained mean values of 226Ra, 232Th, and 40K in the two campuses were 25.48 Bq/kg, 65.96 Bq/kg, and 39.14 Bq/kg for Campus 1 and 24.50 Bq/kg, 66.71 Bq/kg, and 28.19 Bq/kg for Campus 2, respectively. In terms of health analysis, some radiation health hazard parameters were calculated within the two campuses. The mean values of radium equivalent activity were 122.81 Bq/kg and 122.08 Bq/kg, absorbed dose rate in air was 99.13 nGy/h and 98.18 nGy/y, annual outdoor effective dose was 0.12 mSv/y and 0.12 mSv/y, and external health hazard index was 0.34 and 0.33 in Campus 1 and Campus 2, respectively. These health hazard parameters were seen to be below the safe limit of UNSCEAR 2000 except the absorbed dose rate in air and the annual outdoor effective doses which are relatively high compared to the values of 60 nGy/h and 0.07 mSv/y. These results reveal no significant radiological health hazards for inhabitance within the study areas. Maurice Moyo Ndontchueng, Eric Jilbert Mekongtso Nguelem, Augustin Simo, Raymond Limen Njinga, and Gembou Shouop Cébastien Joël Copyright © 2014 Maurice Moyo Ndontchueng et al. All rights reserved. Development and Validation of UV Spectrophotometric Method for Simultaneous Estimation of Hesperidin and Diosmin in the Pharmaceutical Dosage Form Mon, 30 Dec 2013 11:20:39 +0000 A simple, rapid, precise and highly selective spectrophotometric method was developed for simultaneous estimation of Hesperidin and Diosmin in tablet dosage form. This method, involves the measurement of absorbances of Hesperidin and Diosmin at the wavelengths of 285 nm ( of Hesperidin) and 268 nm (, of Diosmin). The UV spectra’s of Hesperidin and Diosmin prepared in different solvents water, methanol, and acetonitrile and 0.2 N sodium hydroxide were recorded. These two drugs showed good absorbances when dissolved in 0.2 N NaOH. Hence 0.2 N NaOH was selected as the solvent for the method. Two wavelengths 285 and 268 nm were selected which are of two drugs Hesperidin and Diosmin, respectively. Different concentrations of Hesperidin (5–50 μg/mL) and Diosmin (2–24 μg/mL) and a mixture of Hesperidin and Diosmin were prepared, scanned and absorbances were noted at the two wavelengths were fixed for the study. The method showed good reproducibility and recovery with % RSD less than 2. The LOD of Hesperidin and Diosmin was found to be 0.139 μg/mL and 0.048 μg/ml and LOQ of Hesperidin and Diosmin was found to be 0.42 μg/mL and 0.147 μg/mL, respectively. Thus the proposed method was found to be rapid, specific, precise, accurate and cost effective quality control tool for the routine analysis of Hesperidin and Diosmin in bulk and combined dosage form. Doddi Srilatha, Mahesh Nasare, Borra Nagasandhya, Valluri Prasad, and Prakash Diwan Copyright © 2013 Doddi Srilatha et al. All rights reserved. A New Analytical Q-Absorbance Ratio Method Development and Validation for Simultaneous Estimation of Lamivudine and Isoniazid Mon, 16 Dec 2013 09:36:13 +0000 A new UV spectrophotometric absorption ratio method was developed and validated for the simultaneous estimation of lamivudine and isoniazid. The method involved Q-absorption ratio analysis using two wavelengths, with one being the of lamivudine (272 nm, ) and the other being the isoabsorptive point of both drugs (246 nm, ). Beer’s law was obeyed in the concentration range between 5 and 30 µg/mL for both lamivudine and isoniazid. The results of analysis have been validated statistically and by recovery studies as per ICH guidelines. The accuracy ranged between 99.65 and 101.91% and Sandell’s sensitivity ranged between 0.0229 and 0.0347 µg/cm2. The method was found to be simple, precise, reproducible, rapid, and economical. Hence, it could be used in the analysis of laboratory samples and marketed formulations containing these two drugs in the future. Gitu Pandey and Brahmeshwar Mishra Copyright © 2013 Gitu Pandey and Brahmeshwar Mishra. All rights reserved. A Recent Review on Chemiluminescence Reaction, Principle and Application on Pharmaceutical Analysis Tue, 26 Nov 2013 09:19:08 +0000 This paper provides a general review on principle of chemiluminescent reactions and their recent applications in drug analysis. The structural requirements for chemiluminescent reactions and the different factors that affect the efficiency of analysis are included in the review. Chemiluminescence application in immunoassay is the new version for this review. Practical considerations are not included in the review since the main interest is to state, through the aforementioned applications, that chemiluminescence has been, is, and will be a versatile tool for pharmaceutical analysis in future years. Tadesse Haile Fereja, Ariaya Hymete, and Thirumurugan Gunasekaran Copyright © 2013 Tadesse Haile Fereja et al. All rights reserved. Characterization of Arsenic Biotransformation Products from an Open Anaerobic Degradation of Fucus distichus by Hydride Generation Gas Chromatography Atomic Absorption Spectrometry and High Performance Liquid Chromatography Inductively Coupled Plasma Mass Spectrometry Sat, 02 Nov 2013 14:31:18 +0000 This work reports on the isolation and determination of biotransformation products obtained from the organoarsenic compounds that are present in Fucus distichus when it was subjected to an open anaerobic decomposition by using the Hydride Generation Gas Chromatography Atomic Absorption Spectrometry (HG-GC-AAS) and High Performance Liquid Chromatography Inductively Coupled Plasma Mass Spectrometry (HPLC-ICP-MS). The seaweed and filtrate residues obtained from the open anaerobic degradation procedure were extracted in methanol and partitioned in phenol-ether-water mixtures to obtain water soluble extracts. The water soluble extracts were cleaned up and separated on a gel permeation Sephadex G15 column. Arsenic species concentrations were determined by using HG-GC-AAS. Final characterization of the biotransformation isolates was carried out on HPLC-ICP-MS. Only two arsenic species, 2-dimethylarsinoyl ethanol (DMAE) and dimethylarsinic acid (DMAA), were positively identified in the water soluble extract of the marine brown algae. The two arsenic species are strong intermediate candidates in the biosynthesis of arsenobetaine from oceanic arsenate in marine food webs. Abiodun A. Ojo and Amos Onasanya Copyright © 2013 Abiodun A. Ojo and Amos Onasanya. All rights reserved. Development and Validation of RP-HPLC Method for Azilsartan Medoxomil Potassium Quantitation in Human Plasma by Solid Phase Extraction Procedure Sat, 14 Sep 2013 14:15:59 +0000 Simple and rapid reverse phase high-performance liquid chromatography (RP-HPLC) method was developed and validated using solid phase extraction (SPE) technique for the determination of Azilsartan Medoxomil Potassium (AMP) in human plasma; detection was carried out by photo diode array detector. Chromatographic separation of the analyte AMP was achieved within 7.5 min by Waters symmetry C18 (4.6 × 250 mm, 5 µm) column, mobile phase was 25 mM ammonium acetate buffer (pH 5.5): acetonitrile 55 : 45 v/v, flow rate was 1.0 mL/min, and the detection was carried out at 254 nm. Calibration curve was linear (r2 > 0.9985) in the range of 1.0–9.0 µg/mL, limit of detection (LOD) and limit of quantitation (LOQ) were 0.150 µg/mL and 0.400 µg/mL, respectively, and intra- and interday deviations were between 1.53–8.41% and 1.78–4.59%, respectively. The overall mean recovery of AMP was 92.35%. No any endogenous constituents were found to interfere at retention time of the analyte. This new RP-HPLC method was successfully validated and may be applied to conduct bioavailability and bioequivalence studies of AMP. Paras P. Vekariya and Hitendra S. Joshi Copyright © 2013 Paras P. Vekariya and Hitendra S. Joshi. All rights reserved. Surfactant Sensitized Calix[4]arenes Fluorescence Quenching Method for Speciation of Cr(VI)/Cr(III) in Water Samples Mon, 02 Sep 2013 15:37:37 +0000 The surfactant sensitized spectrofluorimetry for speciation of chromium (Cr(VI)/Cr(III)) was developed. The analytical procedure was that the fluorescence intensity of l4,10,16,22-tetramethoxyl resorcinarene carboxylic acid derivatives (TRCA) could be selectively quenched by Cr(VI) and the fluorescence quenching value () was increased in cetyltrimethylammonium bromide (CTAB). The main influence factors on the fluorescence quenching (ΔF) were investigated in detail. Under the optimal conditions, the linear range of calibration curve for the determination of Cr(VI) was 0.10~5.00 μg/mL, and the detection limit was 0.024 μg/mL with % ( μg/mL, ). The concentration of Cr(III) was calculated by subtracting Cr(VI) from the total chromium determined after oxidizing Cr(III) to Cr(VI). The preliminary sensitized mechanism was discussed with the inclusion constant (K) of TRCA-Cr(VI), the fluorescence quantum yield of TRCA, and IR spectra characterization. The method has been applied to the speciation analysis of Cr(VI)/Cr(III) in water samples. Wenjun Wang, Xiashi Zhu, and Chaoguo Yan Copyright © 2013 Wenjun Wang et al. All rights reserved. Sensitive Spectrophotometric Determinations of Paracetamol and Protriptyline HCl Using 3-Chloro-7-hydroxy-4-methyl-2H-chromen-2-one Mon, 05 Aug 2013 08:55:53 +0000 A new spectrophotometric method is developed for the determination of Paracetamol (PCT) and protriptyline HCl (PTP) in pure forms and in pharmaceutical formulations. The experiment involves the use of 3-chloro-7-hydroxy-4-methyl-2H-chromen-2-one as a novel chromogenic reagent for the determination of PCT and PTP. The method is based on the formation of charge transfer complex between the drugs and chromogenic reagent. Beer's law is obeyed in the concentration ranges 10.00–60.00 µg mL−1 for PCT at 545 nm and 40.00–160.00 µg mL−1 for PTP at 468 nm. The molar absorptivity, Sandell, sensitivity, and limit of detection and quantification are also calculated. The method has been successfully applied for the determination of both PCT and PTP in pharmaceutical samples with acceptable results. Kumble Divya, Badiadka Narayana, and Majal Sapnakumari Copyright © 2013 Kumble Divya et al. All rights reserved. Identification of Asbestos Using Laser-Induced Breakdown Spectroscopy: A Viable Alternative to the Conventional Approach? Tue, 25 Jun 2013 13:48:43 +0000 Laser-induced breakdown spectroscopy has been performed on isolated samples of six types of asbestos—Chrysotile, Crocidolite, Amosite, Anthophyllite, Actinolite, and Tremolite—with analysis of optical emission in the visible region of the spectrum. The principal elements of Mg, Fe, Si, Na, and Ca have all been identified. By examining peak intensity ratios of these elements it is possible to identify the type of asbestos under examination solely from internal examination of the sample spectra. LIBS offers some significant advantages of speed of analysis and removal of subjectivity with potential for on-site rapid analysis. David M. Benton Copyright © 2013 David M. Benton. All rights reserved. A Sensitive Spectrophotometric Estimation of Nimodipine in Tablets and Injection Using Phloroglucinol Thu, 23 May 2013 09:20:36 +0000 A rapid, simple, and sensitive spectrophotometric method has been described for the determination of nimodipine in bulk drug, tablets, and injection. The proposed method is based on the diazotization of reduced nimodipine with nitrous acid followed by coupling with phloroglucinol to form colored azo dye and showing absorption maximum () at 410 nm. The formed colored azo dye is stable for about more than 2 h. The method obeyed Beer’s law over the concentration range of 0–25 μg/mL and the corresponding molar absorptivity value is  L/moL/cm. The Sandell sensitivity values limits of detection (LOD) and quantification (LOQ) values have also been reported for the developed method. The accuracy and precision of the method was evaluated on intra- and interday basis; the relative error (%RE) and the relative standard deviation (RSD) were <2.0%. All variables have been optimized and the presented reaction sequence was applied to the analysis of nimodipine in bulk drug, tablets, and injections. The performance of this method was evaluated in terms of Student’s -test and variance ratio -test to find out the significance of proposed method over the reference method. Hemavathi N. Deepakumari and Hosakere D. Revanasiddappa Copyright © 2013 Hemavathi N. Deepakumari and Hosakere D. Revanasiddappa. All rights reserved. Simultaneous Estimation of Pantoprazole Sodium and Levosulpiride in Capsule Dosage Form by Simultaneous Equation Spectrophotometric Method Thu, 09 May 2013 14:12:47 +0000 A simple, accurate, and precise spectrophotometric method was developed for simultaneous estimation of pantoprazole sodium and levosulpiride in capsule dosage form. Simultaneous equation was developed at 290 and 232 nm. The method was found to be linear in the range of 4–12 μg/mL for pantoprazole sodium and 8–20 μg/mL for levosulpiride while accuracy of the method was confirmed by recovery studies of capsule dosage form and was found to be 100.23–100.99% and 100.51–100.94% for pantoprazole sodium and levosulpiride, respectively, in their capsule dosage form. The proposed method was validated and found to be accurate and precise. The method was successfully applied for the estimation of pantoprazole sodium and levosulpiride from their capsule dosage form. Dimal A. Shah, Akash Patel, Sunil L. Baldania, Usmangani K. Chhalotiya, and Kashyap K. Bhatt Copyright © 2013 Dimal A. Shah et al. All rights reserved. A Stability Indicating Assay Method Development and Validation for the Frovatriptan Succinate Monohydrate by Using UV: A Spectrophotometric Technique Thu, 02 May 2013 11:55:03 +0000 A new simple, reliable, inexpensive, and accurate method was developed for the quantification of Frovatriptan Succinate Monohydrate in different physiological media at 244 nm in bulk and in tablet dosage forms. The developed method is an attempt to surpass the disadvantages associated with the reported methods, namely, less sensitive and tedious in usage for routine purposes. Beer’s law was followed over the range of 1.0 µg/mL to 4.5 µg/mL. Stability indicating assay method was developed and validated as per the ICH guidelines using various parameters, for example, accuracy, precision, limit of quantification, limit of detection, robustness, ruggedness, solution stability, recovery, forced degradation (hydrolysis, photo degradation, thermal degradation, and oxidation), and so forth. Percent relative standard deviation associated with all the parameters was less than 2, showing compliance with the acceptance criteria of ICH guidelines. The developed method was very sensitive as limit of quantification and limit of detection were found to be 0.025 µg/mL and 0.00625 µg/mL, respectively. Forced degradation studies of drug reveal good stability under the chosen experimental conditions. Hitesh Verma, Surajpal Verma, and Harmanpreet Singh Copyright © 2013 Hitesh Verma et al. All rights reserved. Simple and Selective Spectrophotometric Determination of Ofloxacin in Pharmaceutical Formulations Using Two Sulphonphthalein Acid Dyes Tue, 23 Apr 2013 15:12:26 +0000 Two new simple and sensitive extraction-free spectrophotometric methods have been established for the determination of ofloxacin (OFX). The methods are based on ion-pair complex formation reaction between OFX and acidic sulphonphthalein dyes, bromocresol purple (method A), and bromocresol green (method B) in dichloromethane. The experimental variables such as reaction medium, reaction time, and reagent concentration have been carefully optimized to achieve the highest sensitivity. Both dyes react spontaneously with OFX to give yellow-colored complexes. Beer’s law is obeyed over the concentration ranges of 1.0–16 µg ml−1 OFX with correlation coefficient of 0.999 in both methods. The molar absorptivity values are calculated to be and l mol−1 cm−1, for method A and method B, respectively, with corresponding Sandell's sensitivity values of 0.015 and 0.019 µg cm−2. The limits of detection (LOD) and quantification (LOQ) are also reported. A Job’s plot of the absorbance versus the molar ratio of OFX to each of dyes under consideration indicated (1 : 1) ratio and the conditional stability constant () of the complexes have been calculated. The proposed methods were applied successfully to the determination of OFX in tablets with good accuracy and precision and without interference from common additives. The results obtained by the proposed methods were compared favorably with those of the reference method. Kudige N. Prashanth, Kanakapura Basavaiah, and Madihalli S. Raghu Copyright © 2013 Kudige N. Prashanth et al. All rights reserved. Internal Energy Level Population Redistribution of Carbon Dioxide in Laminar and Turbulent Flow Wed, 10 Apr 2013 15:45:19 +0000 We show clear experimental evidence that in the laminar flow regime, there is a continuous redistribution of population on different vibrorotational energy levels as the flow rate increases. Such redistribution comes to an abrupt stop when the flow changes to turbulence. The population distribution then remains almost unchanged even up to the flow rate 10 times the laminar to turbulent transition. The flow status of carbon dioxide is therefore closely related to its internal energy level population distribution. Wisely Wong, Zhiyu Yang, and Amador Muriel Copyright © 2013 Wisely Wong et al. All rights reserved. Platinum and Palladium Polyamine Complexes as Anticancer Agents: The Structural Factor Sun, 24 Feb 2013 15:58:00 +0000 Since the introduction of cisplatin to oncology in 1978, Pt(II) and Pd(II) compounds have been intensively studied with a view to develop the improved anticancer agents. Polynuclear polyamine complexes, in particular, have attracted special attention, since they were found to yield DNA adducts not available to conventional drugs (through long-distance intra- and interstrand cross-links) and to often circumvent acquired cisplatin resistance. Moreover, the cytotoxic potency of these polyamine-bridged chelates is strictly regulated by their structural characteristics, which renders this series of compounds worth investigating and their synthesis being carefully tailored in order to develop third-generation drugs coupling an increased spectrum of activity to a lower toxicity. The present paper addresses the latest developments in the design of novel antitumor agents based on platinum and palladium, particularly polynuclear chelates with variable length aliphatic polyamines as bridging ligands, highlighting the close relationship between their structural preferences and cytotoxic ability. In particular, studies by vibrational spectroscopy techniques are emphasised, allowing to elucidate the structure-activity relationships (SARs) ruling anticancer activity. M. P. M. Marques Copyright © 2013 M. P. M. Marques. All rights reserved. Recent Applications of Mass Spectrometry in the Study of Grape and Wine Polyphenols Sun, 27 Jan 2013 07:31:59 +0000 Polyphenols are the principal compounds associated with health benefic effects of wine consumption and in general are characterized by antioxidant activities. Mass spectrometry is shown to play a very important role in the research of polyphenols in grape and wine and for the quality control of products. The soft ionization of LC/MS makes these techniques suitable to study the structures of polyphenols and anthocyanins in grape extracts and to characterize polyphenolic derivatives formed in wines and correlated to the sensorial characteristics of the product. The coupling of the several MS techniques presented here is shown to be highly effective in structural characterization of the large number of low and high molecular weight polyphenols in grape and wine and also can be highly effective in the study of grape metabolomics. Riccardo Flamini Copyright © 2013 Riccardo Flamini. All rights reserved. The Combined Optimization of Savitzky-Golay Smoothing and Multiplicative Scatter Correction for FT-NIR PLS Models Thu, 17 Jan 2013 16:46:48 +0000 The combined optimization of Savitzky-Golay (SG) smoothing and multiplicative scatter correction (MSC) were discussed based on the partial least squares (PLS) models in Fourier transform near-infrared (FT-NIR) spectroscopy analysis. A total of 5 cases of separately (or combined) using SG smoothing and MSC were designed and compared for optimization. For every case, the SG smoothing parameters were optimized with the number of PLS latent variables (), with an expanded number of smoothing points. Taking the FT-NIR analysis of soil organic matter (SOM) as an example, the joint optimization of SG smoothing and MSC was achieved based on PLS modeling. The results showed that the optimal pretreatment was successively using SG smoothing and MSC, in which the SG smoothing parameters were 4th degree of polynomial, 2nd-order derivative, and 67 smoothing points, the best corresponding , RMSEP, and were 7, 0.3982 (%), and 0.8862, respectively. This result was far better than those without any pretreatment. The combined optimization of SG smoothing and MSC could obviously improve the modeling result for NIR analysis of SOM. In addition, a new method for the classification of calibration and prediction was proposed by normalization principle. The optimizations were done on this basis of this classification. Huazhou Chen, Qiqing Song, Guoqiang Tang, Quanxi Feng, and Liang Lin Copyright © 2013 Huazhou Chen et al. All rights reserved. C–H⋯F Hydrogen Bond and Integral Intensities of Vinyl C–H Vibtations in Push-Pull β-Dimethylaminotrifluoromethyl Ketone and Its Deuterated Analog Thu, 17 Jan 2013 15:04:07 +0000 The accurate analysis of infrared spectra (both wavenumbers and intensities) of (E)-4-(dimethylamino)-1,1,1-trifluorobut-3-en-2-one (DMTBN) and (E)-4-(hexadeutero-dimethylamino)-1,1,1-trifluorobut-3-en-2-one (d6-DMTBN) revealed that besides intramolecular hydrogen bond in the (EE) conformer, these enaminoketones form cyclic dimers between the (EZ) and (EE) conformers due to intermolecular hydrogen bonds, namely, O=C and . Evaluation of constant and enthalpy of formation of these H-bonds revealed that O=C bond has greater and more negative than bond (cf. 214.4 M−1, −21.7 kJ M−1dm3, and 16.4 M−1, −6.7 kJ M−1dm3, resp.). Consequently, stronger H-bond ⋯O=C is formed in the first place, whereas weaker H-bond is formed afterward. Moreover, formation of intermolecular hydrogen bond has influence on C–F vibrations, but analysis of this influence must take into account the fact that these vibrations in some cases are coupled with . True enthalpy of the equilibrium (EZ)⇌(EE) is positive (25.3 kJ M−1dm3), thus confirming results of DFT calculations, according to which the (EZ) conformer is more stable than the (EE) one. Sergei Vdovenko, Igor Gerus, Elena Fedorenko, and Valery Kukhar Copyright © 2013 Sergei Vdovenko et al. All rights reserved. Ambient Zinc K-Edge Extended X-Ray Absorption Fine Structure Studies on Solid Solution Hardening of the Ternary Alloys Thu, 10 Jan 2013 14:36:29 +0000 Solid solution hardening can be introduced in the zinc selenide by cationic substitution alloying. We are presenting our studies on gradual development of the hardening and the bond-length variations among the heavily Be-doped ternary alloys of . These compositionally vivid ternary systems are grown by the Bridgman technique, and a set of careful measurements of synchrotron-based Zn core X-ray absorption spectroscopy are performed on the mixed alloy, which is followed by extraction of useful oscillations of extended X-ray absorption fine structures. A detailed ab initio analysis is also carried out for the mixed alloy’s theoretical EXAFS simulations, and suitable data processing codes are used for the subsequent experimental spectra fittings. Various X-ray scattering single and multiple paths around the core atomic environ are simulated and compared with the spectroscopic results. With the aid of as-found parametric values, the hardening and crystalline disorders are discussed and explained in the midst of the multimodal bond-length behaviors and changes induced by the increased alloying amid as-found pseudocrystalline stabilities. Shabina Khan, Javed Mazher, and Pankaja Singh Copyright © 2013 Shabina Khan et al. All rights reserved. Use of Charge Transfer Complexation Reactions for the Spectrophotometric Determination of Sumatriptan in Pharmaceuticals Mon, 31 Dec 2012 14:39:49 +0000 Studies were carried out to use the charge-transfer reactions of sumatriptan (SMT), extracted from neutralized sumatriptan succinate (STS), as n-electron donor with the π-acceptor, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and σ-acceptor, and iodine (I2). The formation of the colored complexes was utilized for the development of simple, rapid, and accurate spectrophotometric methods for the determination of SMT in pure form as well as in its tablets. The quantification of colored products was made spectrophotometrically at 585 nm for the CT complex formed between SMT and DDQ (DDQ method) and at 375 nm for the CT complex formed between SMT and I2 (I2 method). Beer’s law is obeyed over the concentration ranges of 4.0–56.0 μg mL−1 and 2.0–28.0 for DDQ and I2, respectively, with correlation coefficients () of 0.9997 and 0.9998. The analytical parameters such as apparent molar absorptivity, Sandell’s sensitivities, and limits of detection (LOD) and quantification (LOQ) are also reported for both methods. The described methods were successfully applied to the determination of SMT in tablets. No interference was observed from the common excipients present in tablets. The reaction stoichiometry in both methods was evaluated by Job’s method of continuous variations and was found to be 1 : 1 (donor : acceptor). Kudige N. Prashanth, Basavaiah Kanakapura, Madihalli S. Raghu, and Kanakapura B. Vinay Copyright © 2012 Kudige N. Prashanth et al. All rights reserved. Structural and Physical Properties of ZnO Modified Bismuth Silicate Glasses Sun, 30 Dec 2012 18:12:58 +0000 Zinc bismuth silicate glasses with compositions (, and 40) have been prepared by conventional melt-quench technique and the solubility limit of zinc in bismuth silicate glass system has been estimated using X-ray diffraction technique. Density has been measured using Archimedes' principle; with increase in ZnO in the samples, the molar volume and density are found to decrease. The glass transition temperature () has been determined by using differential scanning calorimetry (DSC) and is observed to increase with increase in ZnO content. Raman and FTIR spectra have been recorded at room temperature and the analysis of Raman and FTIR shows that in all the glass compositions, asymmetric and symmetric stretched vibrations of Si–O bonds in SiO4 tetrahedral units exist and with decrease in Bi2O3, the contribution of symmetric vibrations begins to dominate which results in increased compactness of the glass structure. J. Hooda, R. Punia, R. S. Kundu, Sunil Dhankhar, and N. Kishore Copyright © 2012 J. Hooda et al. All rights reserved. A Novel Solid Substrate Room Temperature Phosphorimetry for the Determination of Trace Cytochrome C and Forecast of Human Diseases Wed, 26 Dec 2012 12:58:20 +0000 The reaction between fullerenol (F-ol) and cytochrome C (Cyt C) could be carried out to form a nonphosphorescence compound using tween-80 as photosensitizer which causes the sharp quenching of room temperature phosphorescence (RTP) of F-ol. Bearing this in mind, a novel solid substrate room temperature phosphorimetry (SSRTP) for the determination of trace Cyt C has been proposed in this study. Under the optimum conditions, the linear range of this method is –  , which is directly proportional to of Cyt C-F-ol–tween-80 system, and the detection limit (DL) is  . It has been applied to the determination of Cyt C in human serum and forecast of diseases, and the result matches with the enzyme-linked fluorescence immunoassay (ELISA). Meanwhile, the reaction mechanism of SSRTP for the determination of Cyt C and the enhancing effect of tween-80 on RTP of F-ol were also discussed. Zhi-Yong Zheng, Ma-Lin Cui, Jia-ming Liu, Shu-Lian Jiang, Li Jiao, Li-Hong Zhang, Xuan Lin, and Shao-Qin Lin Copyright © 2012 Zhi-Yong Zheng et al. All rights reserved. Use of Alizarin Red S as an Ion-Pair Reagent for the Spectrophotometric Assay of Fexofenadine in Pharmaceuticals and in Spiked Human Urine Wed, 19 Dec 2012 14:55:00 +0000 The present study describes two simple, rapid, selective, and cost-effective spectrophotometric methods for the determination of an antiallergic drug, fexofenadine hydrochloride (FFH), in bulk drug, tablets, and in spiked human urine. The first method (method A) is based on the formation of yellow-colored ion-pair complex between FFH and alizarin red S (AZS) in acid medium which was extracted into dichloromethane, and the absorbance was measured at 440 nm. The second method (method B) is based on the breaking of the yellow FFH–AZS ion-pair complex in alkaline medium followed by the measurement of the violet-colored free dye at 590 nm. Under the optimized conditions, Beer’s law is obeyed over the concentration ranges of 0.4–12.0 and 0.2–3.5 μg  FFH for method A and method B, respectively, and the corresponding molar absorptivity values are 3.80 × 104 and 1.61 × 105 L . The Sandell’s sensitivity, detection, and quantification limits are also reported. The proposed methods were successfully applied to the determination of FFH in pure drug and commercial tablets. The accuracy and reliability of the proposed methods were further established by recovery studies via standard addition technique. Madihalli S. Raghu, Kanakapura Basavaiah, Kudige N. Prashanth, and Kankapura B. Vinay Copyright © 2012 Madihalli S. Raghu et al. All rights reserved. Quick Multicomponent Analysis Based on Matrix Isopotential Synchronous Fluorimetry Tue, 18 Dec 2012 11:14:32 +0000 Fast and precise methods are important in chemical and physical analysis, but determination of concentration of selected components in mixtures may have special difficulties. Excitation-emission matrices (EEM) are widely used in characterizing fluorescence emission. Based on these primary data, we present an improvement of matrix isopotential synchronous fluorimetry (MISF) and a method which ensures a very fast multicomponent analysis. MISF is generally combined with derivative technique (DMISF) to be able to eliminate the contribution of the background emission. Unfortunately, it is too sensitive to noises and fluctuations; thus the concentration region where it can be used, was limited until now. Our first aim was to reduce the influence of measurement errors and to increase the sensitivity of known MISF method by more than one order of magnitude. As a further result, using improved MISF, we got a method which ensures very fast determination of the wanted compound's concentration both in presence of one- or even two-component background of unknown concentration. Géza Makkai and János Erostyák Copyright © 2012 Géza Makkai and János Erostyák. All rights reserved. Microdetermination of Methenamine in the Presence of Formaldehyde by Solid Phase Spectrophotometry Thu, 06 Dec 2012 12:07:31 +0000 A sensitive spectrophotometric method for the determination of methenamine has been developed without any separation steps. Bromocresol green is adsorbed on Sephadex LH-20 gel but the sorption decreases in the presence of methenamine due to ion-pair formation between bromocresol green and methenamine in solution. This attenuation was used to the microdetermination of methenamine by measurement of absorbance of the solid phase (Sephadex LH-20 gel) in a 1.0 mm cell at 625 nm. Methenamine could be determined in the concentration range of 0.42–1.68 μg mL−1 (10-mL Sample volume) with a relative standard deviation (RSD) of 0.03% (). The detection limit obtained was 50 μg L−1 for 10 mL sample volume. The method was used for determination of methenamine in industrial wastewater and a satisfactory result was obtained. Mehdi Taghdiri, Yadollah Yamini, and Ali Moloudi Copyright © 2012 Mehdi Taghdiri et al. All rights reserved. Method Development and Validation of Darifenacin in Rat Plasma by Liquid Chromatography-Tandem Mass Spectrometry: Application to a Pharmacokinetic Study Tue, 27 Nov 2012 11:13:39 +0000 A selective, sensitive, and high-throughput liquid chromatography-tandem mass spectrometry (LC-ESI-MS/MS) method has been developed and validated for the quantitation of darifenacin in rat plasma. Sample clean up involved liquid-liquid extraction (LLE) and used 100 μL of rat plasma. Zorbax, SB C18,  mm, 3.5 μm particle size analytical column using 10 mM ammonium acetate buffer (pH 5) and methanol (10 : 90, v/v) as the mobile phase was used. The parent → product ion transitions for the drug (m/z 427.3 → 147.3) and IS (m/z 431.4 → 151.2) were monitored on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring (MRM) and positive ion mode. The method was validated over the concentration range of 10.00–20000.00 pg/mL for darifenacin. The method was successfully applied into a pharmacokinetic study in rat plasma under fasting conditions. Thejomoorthy Karavadi and B. R. Challa Copyright © 2012 Thejomoorthy Karavadi and B. R. Challa. All rights reserved.