American Journal of Analytical Chemistry

Journal Information
ISSN / EISSN : 2156-8251 / 2156-8278
Current Publisher: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 903
Archived in
SHERPA/ROMEO
Filter:

Latest articles in this journal

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.
Şükrü Kalayci, Şü, Krü
American Journal of Analytical Chemistry, Volume 11, pp 221-231; doi:10.4236/ajac.2020.115018

Abstract:
A new solid state molybdenum-selective electrode has been developed. The electrode is composed of 20% MoS2, 60% Ag2S, and 20% Cu2S. An analytically useful potential change occurred, from 1 × 10-5 to 1 × 10-1 M molybdenum ion. The slope of the linear portion (1 × 10-1 - 1 × 10-5 M) was about 45 ± 2 mV/10-fold concentration changes in molybdenum. It was found that pH change between 1 and 12 had no effect on the potential of the electrode. There was no interference of most common cations such as K+, Na+, Ca2+, Mg2+, Cu2+ and Fe3+ anions such as Cl-, , and . The lifetime of the electrode was more than 2 years, when used at least 4 - 5 times a day, and the response time was about 30 s. This electrode has been used for the determination of molybdenum ion in wine using standard addition method. The validation of the electrode has been made with a commercial molybdenum DP polarography and high consistency was obtained.
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.
Şükrü Kalayci, Ülkü Ünal, Güler Somer, Şü, Krü, ü, Lkü, Gü
American Journal of Analytical Chemistry, Volume 11, pp 187-196; doi:10.4236/ajac.2020.115014

Abstract:
Vitamin B12 is a type of vitamin also known by the name cobalamin. B12 is involved in many metabolism activities, including DNA synthesis, nervous system, red blood formation and immune system. Therefore, we chose the Differential Pulse Polarography (DPP) method is that has a high sensitivity for the determination of vitamin B12. This determination was possible with cobalt present in vitamin B12 structure. Since Co(III) is formed from the oxidation of the vitamin, its polarographic behavior had to be determined in various electrolytes such as acetate, borate, phosphate and ammonia. The polarograms of Co(III) were taken in these electrolytes in which 1.0 M NH3/ (pH = 9.8) and 1.0 M AcOH/AcO- (pH = 4.0) were found as the most suitable electrolytes. This method was successfully applied vitamin of B12 determination in a 1 mL ampoule with high precision. The LOD was found as 3.7 × 10-7 for instead of (S/N = 3). Besides Co(III), interference effects of Zn(II), Ni(II), Cr(III), Fe(III), Cu(II), Cd(II) and Se(IV) were also studied. It was found that only Zn(II) peak had an overlap Co(III) peak in ammonium buffer. This problem could be solved by working in 1.0 M AcOH/AcO- (pH = 4.0) buffer. B12, which is 1000 μg in 1 mL vitamin ampoule, was found for 4 measurements as 999 ± 15 μg as a result of 95% confidence interval.
Ebenezer Frimpong, Liliya Logoyda
American Journal of Analytical Chemistry, Volume 11, pp 335-348; doi:10.4236/ajac.2020.119027

Abstract:
This study was conducted to identify the biological active substances (BAS) from the fruit of Tetrapleura tetraptera obtained from Ghana. TLC, UV Spectroscopy and differential spectrophotometry methods of analysis were employed in this study. Identified BAS included flavonoids, polysaccharides and amino acids. Following state pharmacopoeia of Ukraine (SPU) requirements to validate the developed techniques were employed in this study, and the following validation properties specificity, linearity, range, precision accuracy (convergence) and robustness was determined. These characteristics did not exceed the eligibility criteria as stated in (SPU) Appendix 2. Thus the technique can be made to the SPU monograph on fruits of Tetrapleura tetraptera.
V. Mallikarjuna Sarma, N. V. S. Venugopal, L. Giribabu
American Journal of Analytical Chemistry, Volume 11, pp 289-300; doi:10.4236/ajac.2020.118023

Abstract:
A sensitive and eco-friendly method was developed for the spectrophotometric determination of Lisinopril (LSP) in bulk and pharmaceutical formulations by cloud point extraction technique. The method was based on the formation of a blue-colored coordination complex between Lisinopril (LSP) and Cobalt Thiocyanate (CTC) at a suitable pH. The Complex in aqueous medium was extracted into surfactant layer by cloud point extraction using a non-ionic surfactant Triton X-114 and then the surfactant layer was dissolved in a suitable volume of ethanol and the amount of Lisinopril was determined spectrophotometrically at a wavelength of 625 nm. The conditions like concentration of the drug, concentration of CTC and of Triton X-114, PH, etc. were optimized by OFAT (One Factor At a Time) method. The linear range of calibration curve was 1 - 6 μg/ml and the linear regression equation with a correlation coefficient of 0.99996 was y = 0.0021 + 0.084x. Preconcentration and enrichment factors were found to be 100 and 3.12 respectively, achieving the detection limit of 0.0588 μg/ml. The proposed method was successfully applied for the determination of LSP in the drug formulations. The obtained values were in agreement with the values as quoted by the manufacturers.
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

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.
P. Padmavathi, N. Vasundhara, Swathi Kovvuri, N. V. S. Venugopal
American Journal of Analytical Chemistry, Volume 11, pp 197-204; doi:10.4236/ajac.2020.115015

Abstract:
In present days many types of materials are used to reduce the environmental pollution in the world which includes nanomaterials. Nanopesticides increase the efficacy, durability and reduction in the amount of active constituent. The potential applications of nanotechnology in pesticides are quick decomposition in soil or plant, targeted delivery, apparent solubility and controlled release. In this communication the author reported a neonicatonoid insecticide called as Nano-acetamiprid and it is widely used to control fungal infections in different crops like cotton, leafy vegetables, citrus fruits, pome etc. The author reported a facile method i.e. a new Nano-acetamiprid for plant disease control and its subsequent characterization of encapsulated complex using polycaprolactone as an encapsulated agent. Nano-acetamiprid encapsulated particles were characterized by dynamic light scattering (DLS), ultraviolet spectroscopy and scanning electron microscopy (SEM). To ascertain the formation and the stability of nanoencapsulated acetamiprid pesticide, the maximum absorption spectra formulated at 421 nm and unformulated pesticide at 520 nm were observed. The size distribution was noted at 40 - 50 nm. The bioactivity study was conducted against various Aspergillus niger. The performance of nano particles was many fold times effective when compared to the original parental particles. The bio-assay of Nano-acetamiprid shows better results when compared to the normal commercial acetamiprid.
Catalina Soto-Armenta Laura, C. Sacramento Rivero Julio, Araceli Ruiz-Mercado Claudia, González-Coloma Azucena, Antonio Rocha-Uribe José, Laura Catalina Soto-Armenta, Julio C. Sacramento Rivero, Claudia Araceli Ruiz-Mercado, Azucena González-Coloma, José Antonio Rocha-Uribe
American Journal of Analytical Chemistry, Volume 11, pp 322-334; doi:10.4236/ajac.2020.118026

Abstract:
This study reports the extraction of Jatropha curcas leaves using supercritical CO2. Experiments were performed varying the pressure (13 and 20 MPa) and the temperature (50°C and 60°C). The model of Sovová for supercritical fluid extraction was fitted to the experimental kinetic extraction curves. Two cell sizes were used and scale up equations compared. GC analysis showed phytol, carvacrol, and hexahydrofarnesyl acetone as major compounds in all the experiments. A maximum yield of 0.95% dry-weight basis was obtained. It was observed a maximum yield (0.95% dry-weight basis) extract obtained at 20 MPa and 50°C. The results indicated that the mass yield increased with the increase of pressure. The bioassays showed that the extract of J. curcas possessed toxicity against Hyalomma lusitanicum.
Back to Top Top