SM Analytical and Bioanalytical Techniques

Archive Articles

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Drug Optimization: Fighting Research to Achieve the Greatest Use of Darunavir

A design has been development that provides higher activity to darunavir, an antiretroviral drug, aiming a lower dose in the battle against HIV in children and adults. Globally this research paves the way to get a new darunavir: β-cyclodextrin complex driving future perspectives to new anti HIV drugs for clinical applications. β-cyclodextrins not only promote the solubility of darunavir, but can drive to development of new complexes able to combat HIV in lower doses and, therefore lower toxic effects. Analysis methods by chromatography, also, were developed to evaluated the quality of the complexed darunavir. All this effort to contemplate the patients of all ages and provide quality medicines as well as a better quality of life.

Ana Carolina Kogawa¹ and Hérida Regina Nunes Salgado¹*


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Enhancing Throughput of Glutathione Adduct Formation Studies and Structural Identification Using a Software-Assisted Workflow Based on High-Resolution Mass Spectrometry (HRMS) Data

The bioactivation of drugs to Reactive Metabolites (RM) has been related to drug-induced liver injury and hypersensitivity reactions in patients. Therefore, many pharmaceutical companies are investigating the potential to form reactive metabolites in vitro as an integral part of the optimization of drug candidates. A computer assisted workflow to efficiently analyze larger numbers of compounds for the formation of glutathione trappable RM is presented here. A set of 95 compounds with known bioactivation potential was selected for this study. Incubations with human liver microsomes were prepared with GSH. The acquisition of MS/MS spectra was triggered by ion intensity. MS with singly and doubly charged ions were used for peak detection and MS/MS spectra were used for structural elucidation. A confidence classification system for the GSH peak detection (high, medium, low) was developed based on the detection of characteristic fragment ions or neutral losses and applied to remove potential false positive results. A comparative analysis of the HRMS results with literature data was carried out. The most frequently observed Neutral Loss (NL) found in singly charged GSH adducts (drug-glutathione conjugates) were, the Neutral Loss (NL, 129 Da) and Fragment Ion (FI, m/z 308) and in the doubly charged ones the Fragment Ion (FI, m/z 130). These NL and FI were used to identify GSH-related drug metabolites. MS/MS spectra were inspected to aid structural elucidations: 17% of drug substrates and 29 % of GSH adduct metabolites were identified with only doubly charged ions, stressing the importance of considering this charge state in the identification workflow. A total of 41 compounds that form GSH adducts were retrieved from literature (HRMS, identified 28 compounds (68%) in high confidence, and the same result was obtained using precursor ion scan). By the confidence analysis of GSH peaks, the quality of the each GSH adduct was determined.

Esra Nurten Cece-Esencan¹, Fabien Fontaine², Guillem Plasencia²,³, Marieke Teppner³, Andreas Brink³, Axel Pähler³, and Ismael Zamora⁴*


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Evaluation of Solid Phase Extraction NH2 for Determination of Enniatins (A, A1, B, B1) and Beauvericin in Cereals by UPLC-MS/MS

We report herein, for the first time, the application of NH2 solid-phase extraction NH2 (NH2-SPE) cartridge for cleanup of enniatins (ENA, ENA1 , ENB, ENB1 ) and Beauvericin (BEA) in cereals. Samples were sequentially extracted with a solution containing 80% acetonitrile and 0.1% formic acid and the extracts were cleaned up with NH2-SPE cartridges before being analyzed by Ultra-High Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS/MS). A CORTECS C18 column was used for separation of enniatins and beauvericin. Mass spectrometric analysis was conducted at the Positive Electrospray Ionization (ESI+) Mode with Multi Reactions Monitoring (MRM). Very good linear relationships between spiked levels of ENA, ENA1, ENB, ENB1, BEA in cereals and mass spectra were observed with regression coefficients of 0.995 to 0.999 and Detection Limits (LOD) range of 0.01 to 0.1 µg kg-1. Clean up with NH2-SPE cartridge gave more satisfactory recoveries ranging from 80.9% to 109.8% than with QuEChERS method that gave recoveries between 63.5% to 96.6%. Application of the NH2-SPE cartridge for the determination of enniatins and beauvericin showed detection levels ranging from 0.01 µg kg-1 to 127.87 µg kg-1 in corn and 0.01 µg kg-1 to 116.59 µg kg-1 for wheat.

Juan Sun, Weixi Li, Yan Zhang, Huijie Zhang, Li Wu, Xuexu Hu and Bujun Wang*


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Electroanalysis: Towards a

Recent trends in the sensor community, indicates that one of the major challenges and opportunities of the field relies on developing smart sensor platforms, which are cheap, efficient, easy-to-use, and capable of minimizing tasks at the end user stage, in comparison to traditionally used methods which require bulky instrumentations and qualified personnel.

Stefano Cinti*


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Chemistry in Sustainability and Chemistry of Sustainability: Waste of use of Fishing Industry for Removal of Waste Textile Industry

One of the negative consequences related to socioeconomic development in recent centuries has been the rise of environmental contamination. In light of this, human has sought to implement actions in all spheres (social, economic and cultural) aiming to minimize the impact on the environment. Concern about the pollution of bodies of water and industrial wastewater treatment is the biggest worry in this regard. Among various treatment methods highlights the adsorption solid phase, by being very efficient and economically feasible. The use of chitosan as an adsorbent makes the process more ecologically interesting, once chitosan is also retrieved from waste. In this study we evaluate the adsorption process of the bromothymol blue dye by the chitosan. The parameters that influence the sorption process were studied (pH, ionic strength, adsorbent mass and dye initial concentration), and the process thermodynamics.

Francisco JE¹, Cajé JCM¹, Semaan FS¹, and Pacheco WF¹*