American Journal of Analytical Chemistry

Journal Information
ISSN / EISSN : 21568251 / 21568278
Current Publisher: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 898
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Hyo Kan, Ryo Mizutani, Kazuhiko Tsukagoshi
American Journal of Analytical Chemistry, Volume 11, pp 15-24; doi:10.4236/ajac.2020.111002

Abstract:
Peroxyoxalate chemiluminescence was, for the first time, examined by using ternary mixed solutions of water-hydrophilic/hydrophobic organic solvent. Eosin Y as a model fluorescence compound was dissolved with the ternary solutions of water (1.0 mM carbonate buffer, pH 9.0)-acetonitrile-ethyl acetate, water-rich of 15:3:2 volume ratio and organic solvent-rich of 3:8:4 volume ratio, to which bis(2,4,6-trichlorophenyl) oxalate and hydrogen peroxide chemiluminescence reagent were added. The chemiluminescence observed with the ternary solutions, especially the organic solvent-rich solution, showed a larger signal than that observed with the water only solution or water-acetonitrile mixed solution. Chemiluminescence in the presence of twenty types of α-amino acid was similarly examined by using the ternary organic solvent-rich solution. The chemiluminescence of three α-amino acids with fluorescence properties was enhanced with the ternary solution. The data reported here may contribute to development of a new, sensitive peroxyoxalate chemiluminescence detection system.
Lucile Tiemi Abe-Matsumoto, Geni Rodrigues Sampaio, Deborah Helena Markowicz Bastos
American Journal of Analytical Chemistry, Volume 11, pp 269-279; doi:10.4236/ajac.2020.117021

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Carla Zarazir, Mohamad Rajab, Houssam Obeid, Joumana Toufaily, Imad Toufeili, Tayssir Hamieh
American Journal of Analytical Chemistry, Volume 11, pp 129-136; doi:10.4236/ajac.2020.113010

Idris Aminu, Sani M. Gumel, Wasila A. Ahmad, Adamu A. Idris
American Journal of Analytical Chemistry, Volume 11, pp 47-59; doi:10.4236/ajac.2020.111004

Abstract:
In this study, adsorption of Congo red dye onto activated carbon prepared from Jujube (Ziziphus Mauritiania) seeds with phosphoric acid as the activating agent was investigated. Batch adsorption studies were carried out to study the influence of contact time, adsorbent dosage and initial dye concentration on the adsorption. The data was analysed using pseudo-first order and pseudo-second order kinetic models. The pseudo-second order kinetic model was found to describe the adsorption more effectively with a perfect correlation coefficient of unity. The rate constant, K was obtained as 0.182 (g/mg min) and the calculated qe (9.81) is very close to the experimental value (9.78). A high correlation coefficient obtained when the data was analysed with the intraparticle diffusion rate equation, revealed the presence of intraparticle diffusion in the adsorption process even though it is not the sole controlling step as shown by the value of the intercept (C ≠ 0). Isotherm studies showed that there is high correlation in each case when the data was modelled with Langmuir, Freundlich, Temkin and Dubinin-Radushkevic isotherm models but the best fit was obtained with the Freundlich model with R2 = 0.9991, adsorption capacity, KF = 19.73 (mg/g)(mg/L)1/n and n = 1.563 indicating the adsorption is favourable and occurs on a heterogeneous surface by multilayer. The study showed that activated carbon from jujube seeds is an effective adsorbent for the removal of Congo red dye from solution.
Satoshi Ikeda, Saya Morioka, Yoshihiro Kudo
American Journal of Analytical Chemistry, Volume 11, pp 25-46; doi:10.4236/ajac.2020.111003

Abstract:
Ionic strength conditions in distribution experiments with single ions are very important for evaluating their distribution properties. Distribution experiments of picrates (MPic) with M = Ag(I) and Li(I)-Cs(I) into o-dichlorobenzene (oDCBz) were performed at 298 K by changing volume ratios (Vorg/V) between water and oDCBz phases, where “org” shows an organic phase. Simultaneously, an analytic equation with the Vorg/V variation was derived in order to analyze such distribution systems. Additionally, the AgPic distribution into nitrobenzene (NB), dichloromethane, and 1,2-dichloroethene (DCE) and the NaB(C6H5) 4 (=NaBPh4) one into NB and DCE were studied at 298 K under the conditions of various Vorg/V values. So, extraction constants (Kex) for MPic into the org phases, their ion-pair formation constants (KMA,org) for MA = MPic in the org ones, and standard distribution constants () for the M(I) transfers between the water and org bulk phases with M = Ag and Li-Cs were determined at the distribution equilibrium potential (dep) of zero V between the bulk phases and also the Kex (NaA), KNaA,org, and values were done at A-=BPh-4. Here, the symbols Kex, KMA,org, and or were defined as [MA] org/[M+][A-], [MA] org/[M+]org [A-]org, and [M+]org/[M+] or [A-]org/[A-] at dep = 0, respectively. Especially, the ionic strength dependences of Kex and KMPic,org were examined at M = Li(I)-K(I) and org = oDCBz. From above, the conditional distribution constants, KD,BPh4 and KD,Cs, were classified by checking the experimental conditions of the I, Iorg, and dep values.
Léopoldine Sonfack Guenang, Prachi Gupta, Victor Costa Basseto, Milica Jovic, Ervice Ymélé, Andreas Lesch, Hubert Girault, Ignas Kenfack Tonlé
American Journal of Analytical Chemistry, Volume 11, pp 1-14; doi:10.4236/ajac.2020.111001

Abstract:
In this work, a simple procedure for the preparation of an inkjet printed disposable graphene electrode is reported. Commercial graphene ink was printed on a kapton substrate and the resulting electrode was 30 min treated by oxygen plasma, then modified by a bismuth salt. The as prepared electrode was characterized by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), laser scanning microscopy (LSM) and scanning electron microscopy (SEM) coupled to energy-dispersive X-ray spectroscopy (EDX). The sensing properties of the characterized electrodes were then investigated using cyclic voltammetry and Electrochemical Impedance Spectroscopy (EIS). Afterwards, these electrodes were exploited in a comparative way for the electroanalysis of Cadmium(II) and Lead(II) ions. An increase in the electrode sensitivity due to its modification and to the presence of bismuth was observed. Some preliminary experiments based on stripping square wave voltammetry highlighted the interest of using the proposed disposable inkjet printed electrodes for the electrochemical detection of heavy metals in tap water.
K. Saranya, V. Mohan, L. Rajendran
American Journal of Analytical Chemistry, Volume 11, pp 172-186; doi:10.4236/ajac.2020.114013

Abstract:
In this paper, mathematical models of biofilm mixtures of n-butanol biofilters were discussed. The model is based on the mass transfer in the biofilm interface and chemical oxidation in the biofilm phase and gas phase. An approximate analytical expression of concentration profiles of n-butanol in the biofilm phase and gas phase has been derived using the homotopy perturbation method and hyperbolic function method for all possible values of parameters. Furthermore, in this work, the numerical simulation of the problem is also reported using the Matlab program. Good agreement between the analytical and numerical results is noted. Graphical results are presented and discussed quantitatively to illustrate the solution. The analytical results will be useful in finding the yields of biomass and oxygen consumption, the specific biomass surface area, activation energy and saturation constant for the Michaelis-Menten kinetics.
Birame Ndiaye, Momar Ndiaye, Benita Pérez Cid, Abdoulaye Diop, Ibrahima Diagne, Dame Cissé, Cheikh Tidiane Dione, Maoudo Hanne
American Journal of Analytical Chemistry, Volume 11, pp 137-145; doi:10.4236/ajac.2020.113011

Ali Hayek, Nabil Tabaja, Samir Abbad Andaloussi, Joumana Toufaily, Evelyne Garnie-Zarli, Abbas El Toufaili, Tayssir Hamieh
American Journal of Analytical Chemistry, Volume 11, pp 90-103; doi:10.4236/ajac.2020.112007

Abstract:
Water security is a very important purpose facing the world in the last decay as one of the main consequences related to the risks of climate change. Water quality of Litani River’s at Quaraoun Lake station in Lebanon was evaluated by measuring various physicochemical parameters between 2008 and 2018. Samples were performed and analyzed the first of every month. Different analytical methods were used to determine the values of 11 physico-chemical parameters. Different statistical methods, such as Principal Component Analysis and the Times Series Representation, were applied to the results to evaluate the water characteristics, determine the operation of the ecosystem and study the correlation between the different parameters in the Quaraoun station. Industrial, agricultural and sewage water pollution of the Litani River were demonstrated by the high concentration of sulfate, phosphate and ammonia. High bacterial activity was proved from the high decreasing of the dissolved oxygen. Important correlations between the different parameters and between the parameters of the ecosystem and the weather were proved.
Sixia Xiao, Jiemei Chen, Tao Pan
American Journal of Analytical Chemistry, Volume 11, pp 104-113; doi:10.4236/ajac.2020.112008

Abstract:
High-end wine brand is made through the use of high-quality grape variety and yeast strain, and through a unique process. Not only is it rich in nutrients, but also it has a unique taste and a fragrant scent. Brand identification of wine is difficult and complex because of high similarity. In this paper, visible and near-infrared (NIR) spectroscopy combined with partial least squares discriminant analysis (PLS-DA) was used to explore the feasibility of wine brand identification. Chilean Aoyo wine (2016 vintage) was selected as the identification brand (negative, 100 samples), and various other brands of wine were used as interference brands (positive, 373 samples). Samples of each type were randomly divided into the calibration, prediction and validation sets. For comparison, the PLS-DA models were established in three independent and two complex wavebands of visible (400 - 780 nm), short-NIR (780 - 1100 nm), long-NIR (1100 - 2498 nm), whole NIR (780 - 2498 nm) and whole scanning (400 - 2498 nm). In independent validation, the five models all achieved good discriminant effects. Among them, the visible region model achieved the best effect. The recognition-accuracy rates in validation of negative, positive and total samples achieved 100%, 95.6% and 97.5%, respectively. The results indicated the feasibility of wine brand identification with Vis-NIR spectroscopy.
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