A method using UV-Vis spectroscopy and multivariate tools for simultaneous determination of glucose and cholesterol was developed in this paper. The method is based on the development of the reaction between the analytes (cholesterol and glucose) and enzymatic reagents. The spectra were analyzed by partial least squares regression and artificial neural networks. The precision estimated between nominal and calculate concentration demonstrate that artificial neural network model was adequate to quantify both analytes in serum samples, since the &#x25; relative error obtained was in the interval from 5.1 to 8.3. The proposed model was applied to analyze blood serum samples, and the results are similar compared to those obtained employing the reference method.

Jessica Torres-Gamez

Jose A. Rodriguez

M. Elena Paez-Hernandez

Carlos A. Galan-Vidal

Application of Multivariate Statistical Analysis to Simultaneous Spectrophotometric Enzymatic Determination of Glucose and Cholesterol in Serum Samples

An innovative method is validated for the analysis of ertapenem sodium by capillary electrophoresis using potassium phosphate buffer 10&#x2009;mM pH 7 and 15&#x2009;kV voltage, in the concentration range of 70 to 120&#x2009;&#x3bc;g&#x2009;mL&#x2212;1. Ertapenem had a migration time of 3.15 minutes and the linearity curve was y = 2281.7 x - 24495 with a R2 = 0.9994. Thus, we propose a routine analysis method that meets the principles of green analytical chemistry for the routine analysis of ertapenem sodium by capillary electrophoresis.

Tahisa Marcela Pedroso

Ann Van Schepdael

H&#xe9;rida Regina Nunes Salgado

Application of the Principles of Green Chemistry for the Development of a New and Sensitive Method for Analysis of Ertapenem Sodium by Capillary Electrophoresis

The antioxidant potential of a novel additive, named maleimide p-CH3, and the synergistic effect on biodiesel stabilization when combined with a traditional synthetic antioxidant (e.g., propyl gallate (PG)) as well as alternative additives (e.g., alizarin (ALZ) and citric acid (CA)) were investigated. The additives were combined in binary and/or ternary blends at low concentrations and their effectiveness against soybean biodiesel oxidation in the absence and presence of metal was tested. The effectiveness of binary and ternary blends was also evaluated by the Rancimat&#xae; method and compared with total acid number (TAN). The results showed that the combinations presented synergetic effects and were effective in stabilizing biodiesel in accordance with the minimum requirements of EN 14214 and also revealed that the mixture containing PG and p-CH3, even at low concentrations, can be successfully applied for biodiesel preservation. In summary, we report that the biodiesel stability can be obtained by using a reduced amount of additives, suggesting that biodiesel shelf life can be improved in association with a cost reduction when compared to the use of conventional antioxidants.

Silvia S. Yahagi

Ana C. Roveda

Adrielli T. Sobral

Ivan P. Oliveira

Anderson R. L. Caires

Roberto S. Gomes

Magno A. G. Trindade

An Analytical Evaluation of the Synergistic Effect on Biodiesel Oxidation Stability Promoted by Binary and Ternary Blends Containing Multifunctional Additives

Marcela Zanetti Corazza

Vanessa Egea dos Anjos

Seyyed E. Moradi

Extraction/Preconcentration Procedures for Determination of Metal and Organometallic Species in Environmental, Biological, and Food Samples

Subboiling distillation has been used since two decades for the purification of analytical grade acids from inorganic contaminants and demonstrated an efficient method to obtain pure acids starting from reagent grade chemicals. Nevertheless, the effect of the subboiling parameters on the purity of the distilled acids has never been methodically investigated. Aim of the present research is a systematic evaluation of the subboiling distillation protocol for the production of pure hydrochloric and nitric acid. In particular, the effect of the subboiling temperature and the number of subsequent distillations was investigated as these parameters were recognised as the most important factors controlling acid purity, acid concentration, and distillation yield. The concentration of twenty elements in the purified acids was determined by Inductively Coupled Plasma-Mass Spectrometry. As a result, the subboiling temperature (up to 82&#xb0;C) and the number of subsequent distillations (up to four) were demonstrated not to affect the purity of the distilled nitric and hydrochloric acids. Under normal laboratory conditions, the residual elemental concentrations were in most cases below 10 ng/L in both nitric (2.75&#x25; w/w) and hydrochloric (0.1 M) blanks. Ultrapure nitric and hydrochloric acids could accordingly be produced under the most favorable conditions, i.e., the highest temperature and one distillation process only.

Damiano Monticelli

Alessio Castelletti

Davide Civati

Sandro Recchia

Carlo Dossi

How to Efficiently Produce Ultrapure Acids

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International Journal of Analytical Chemistry publishes research reporting new experimental results and chemical methods, especially in relation to important analytes, difficult matrices, and topical samples.

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Chief Editor, Professor Charles L. Wilkins, is a Distinguished Professor of Chemistry and Biochemistry at the University of Arkansas, USA. His research focuses on the development of novel analytical chemistry instrumentation and analysis paradigms.

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International Journal of Analytical Chemistry - Table of contents 2019

International Journal of Analytical Chemistry | Hindawi

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International Journal of Analytical Chemistry publishes research reporting new experimental results and chemical methods, especially in relation to important analytes, difficult matrices, and topical samples.

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International Journal of Analytical Chemistry

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International Journal of Analytical Chemistry