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Sandia Machado, Sara R Fernandes, Luise L Chaves, Sofia A C Lima, Eduarda M P Silva, Luísa Barreiros, Salette Reis, Marcela Alves Segundo
The low bioavailability and non-specific distribution of dapsone and clofazimine, commonly applied in combination for the treatment of leprosy, can produce toxic effects. Nanotechnological approaches enhance the delivery of these drugs. Therefore, a high-performance liquid chromatography method was developed for the simultaneous determination of dapsone and clofazimine loaded in nanoformulations for quality control purposes. Chromatographic separation was achieved on a reversed-phase Kinetex core-shell C18 column, followed by spectrophotometric detection at 280 nm...
July 13, 2018: Journal of Separation Science
Tianjiao Huang, Michael Armbruster, Richard Lee, Dawn S Hui, James L Edwards
Analysis of metabolites is often performed using separations coupled to mass spectrometry which is challenging due to their vast structural heterogeneity and variable charge states. Metabolites are often separated based on their class/functional group which in large part determine their acidity or basicity. This charge state dictates the ionization mode and efficiency of the molecule. To improve the sensitivity and expand the coverage of the mammalian metabolome, multifunctional derivatization with sheathless CE-ESI-MS was undertaken...
July 4, 2018: Journal of Chromatography. A
Beizhan Yan, Masha Pitiranggon, James Ross, Thomas Arthen-Engeland, Andreas Stelter, Steven N Chillrud
This study validates the analysis of polycyclic aromatic hydrocarbons (PAHs) in microgram levels of particulate matter (PM) collected on filters by two low-flow rate, real-time monitors, microPEM™ and microAeth® . Particle-associated PAHs were analyzed by a coupling of a gas chromatograph to a sensitive, atmospheric-pressure laser ionization-mass spectrometer. Air particulate samples were collected over the course of one or two days in the living room of a fourth-floor apartment in New York City. Three types of samplers, the two aforementioned personal samplers and a high-flow rate pump (4 liters per minute), were operated side by side, and three samples of each type were collected during each sampling period...
2018: Journal of Analytical & Bioanalytical Techniques
Marta de Diego, Diana Correa, Sigrid Mennickent, Ricardo Godoy, Carola Vergara
Vortioxetine hydrobromide (VOR), is a novel antidepressant used for the treatment of major depressive disorder. It has a chemical structure susceptible to degradation, therefore, it is important to have suitable analytical methods to determine VOR in presence of its main degradation products (DP), because if the compound degrades, this could result in diminution of the therapeutic activity and safety. A simple HPLC method with photodiode array detection (DAD), was developed and validated for determination of VOR in bulk and tablets, in presence of its major DP...
July 12, 2018: Biomedical Chromatography: BMC
Ersin Demir, Onur Inam, Recai Inam
Proparacaine, one of the most common local anesthetics to facilitate diagnosis and treatment of eye diseases, was assayed by square wave voltammetry using a paste electrode prepared with carbon nanotubes. In cyclic voltammetric studies, proparacaine has exhibited a single irreversible anodic peak at around + 900 mV vs. Ag/AgCl in pH 6.0 Britton-Robinson buffer solution. It was suggested that the peak had appeared due to the oxidation of the NH2 group on the proparacaine molecule. Prior to the determination of the proparacaine by square wave stripping voltammetry (SWSV) on the fabricated multi-walled carbon nanotube paste electrode (MWCNTPE), the accumulation potential (Eacc ), accumulation time (tacc ), pulse amplitude (ΔE), step potential (ΔEs ) and frequency (f ) parameters were optimized...
2018: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Paweł Mateusz Nowak, Katarzyna Olesek, Michał Woźniakiewicz, Paweł Kościelniak
Methcathinone (ephedrone), 4-methylmethcathinone (mephedrone) and 3-methylmethcathinone (metaphedrone) are toxicologically-important cathinone derivatives used commonly as designer drugs. In this work we show the first method allowing to separate simultaneously all these molecules in a chiral medium, ensuring good resolution between all enantiomers. Eight cyclodextrins have been tested as potential chiral selectors, the best results were obtained with 2-hydroxyethyl-β-cyclodextrin, unreported so far for efficient separation of cathinones...
July 11, 2018: Electrophoresis
S Song, H F Yan
Objective: To establish the method for determination of barium sulfate in the air of workplace. Methods: The barium sulfate was collected by dichloride ethylene filter membrane and then processed by alkali fusion method. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used for the detection of barium sulfate. Results: The sampling efficiency was 100%, the linearity of ICP-OES was good at the range of 0.1~100.0 μg/mL, the recovery was ranged from 93.0%~97.8%, the RSD of intra- and inter-batch precision were 3...
April 20, 2018: Chinese Journal of Industrial Hygiene and Occupational Diseases
Gonglin Qu, Xuesong Qi, Shuai Shao, Chen Li, Chunyan Wang, Chengfang Wang, Qiao Gou
Sijunzi decoction (SJZD) is one of the most well-known traditional Chinese herbal formulations. This study elucidates the pharmacokinetics of SJZD in rats' plasma after the administration of a single oral dose of 3 mL/kg using ultra high-performance liquid chromatography electrospray ionization quadrupole-time of flight mass spectrometry (UHPLC-ESI-Q-TOF/MS) with bergapten as an internal standard. The separation was performed on an Agilent Zorbax Eclipse Plus C18 Column (2.1 × 50 mm, 1.8 μm) by elution with acetonitrile and water (containing 0...
July 11, 2018: Biomedical Chromatography: BMC
Ali Benvidi, Zohreh Abbasi, Marzieh Dehghan Tezerjani, Maryam Banaei, Hamid Reza Zare, Hossein Molahosseini, Shahriar Jahanbani
In this study, a simple and novel electrochemical biosensor based on a glassy carbon electrode (GCE) modified with a composite of graphene oxide (GO) - silk fibroin nanofibers (SF) and gold nanoparticles (MCH/ssDNA/AuNPs/SF/GO/GCE) was developed for detection of DNA sequences. The fabrication processes of electrochemical biosensor were characterized by scanning electron microscopy (SEM), FT-IR and electrochemical methods. Some experimental conditions such as immobilization time of probe DNA and MCH incubation time, time and temperature of hybridization were optimized...
June 2018: Acta Chimica Slovenica
Jamshid Salamzadeh, Attaollah Shakoori, Vahideh Moradi
Background: Pesticides are a reason for popular concern due to their possible unfavorable results on human safety. Most pesticide residues are present in food owing to the direct application of a pesticide to a crop. The aims of this study were; development a multiresidue method for analysis of 81 pesticides in tomato using GC/MS, and detection and quantitation of the studied pesticides in tomato samples gathered from various stores of Iran. Methods: The pesticides were assessed concurrently in a single run applying GC/MS after extraction with QuEChERS method...
June 2018: Journal of Environmental Health Science & Engineering
L Kristoffersen, M Langødegård, K I Gaare, I Amundsen, M N Terland, D H Strand
A high-throughput UHPLC-MS/MS method for the most frequently found compounds; tetrahydrocannabinol (THC), amphetamine, methamphetamine, MDMA, clonazepam, diazepam, nordiazepam, oxazepam, alprazolam, nitrazepam, morphine, and codeine, in driving under the influence of drugs (DUID) cases in whole blood, is presented. Automated sample preparation by 96-well supported liquid extraction (SLE) plates with ethyl acetate + heptane (80 + 20, v/v) as organic solvent was carried out on a Freedom Evo 200 platform from Tecan...
June 25, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
José Hugo de Sousa Gomes, Grazielle Caroline da Silva, Steyner F Côrtes, Rodrigo Maia de Pádua, Fernão Castro Braga
The antihypertensive activity of the medicinal plant Hancornia speciosa has been previously demonstrated by us, being the activity ascribed to polyphenols and cyclitols like l-(+)-bornesitol. We herein evaluated the stability of the bioactive marker bornesitol submitted to forced degradation conditions. Bornesitol employed in the study was isolated from H. speciosa leaves. An UHPLC-ESI-MS/MS method was developed to investigate bornesitol stability based on MRM (Multiple Reaction Monitoring) acquisition mode and negative ionization mode, employing both specific (m/z 193 → 161 Da) and confirmatory (m/z 193 → 175 Da) transitions...
June 22, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Nicolas Drouin, Serge Rudaz, Julie Schappler
Extraction of polar endogenous compounds remains an important issue in bioanalysis although different techniques have been evaluated. Among them, electromembrane extraction (EME) is a relevant approach but supported liquid membranes (SLMs) dedicated to polar molecules are still lacking. In this study 22 organic solvents were evaluated as SLMs on a set of 45 polar basic metabolites (log P from -5.7 to 1.5) from various biochemical families. To investigate a large variety of organic solvents, a parallel electromembrane extraction device was used and a constant current approach was applied to circumvent the heterogeneous conductivities of the different SLMs...
June 20, 2018: Journal of Pharmaceutical and Biomedical Analysis
Ying Xiao, Piera Maiolino, Jin-Hua Yan, Jie Ma, Jin Li, Li Chen
In this study, a simple and sensitive LC-MS/MS method was developed and validated for simultaneous determination of icotinib and its four circulating metabolites in human plasma. The analytes were extracted with acetonitrile and separated on a C18 column using 2 mM ammonium acetate containing 0.2% formic acid and acetonitrile as mobile phase. The analytes were introduced into mass spectrometer via electrospray ionization source operated in positive ion mode. Precursor-to-product transitions were optimized to be m/z 392...
July 5, 2018: Biomedical Chromatography: BMC
Amanda Letícia Polli Silvestre, Maria Izabel Milani, Eduardo Luiz Rossini, Leonardo Pezza, Helena Redigolo Pezza
A simple, fast, low-cost, portable, and eco-friendly method using a spot test on a paper platform, together with diffuse reflectance spectroscopy, was developed and validated for the quantification of aluminum hydrochloride, a potential neurotoxic agent, in antiperspirant samples. The determination of aluminum hydrochloride was performed at a wavelength of 615 nm, by measuring consumption of the purple colorimetric reagent Alizarin S, due to reaction with aluminum. The linear range was from 10.0 to 125.0 mg L-1 and could be described by the equation: AR  = 0...
June 15, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Yunus Emre Unsal, Mustafa Tuzen, Mustafa Soylak
> Background: A rapid and new ultrasound-assisted ionic liquid-dispersive liquid-liquid microextraction method (UA-IL-DLLME) was presented for the determination of curcumin by spectrophotometry. Objective: To determine trace levels of curcumin in food samples by using green and low-cost method development. Methods: 1-Butyl-3-methylimidazolium hexafluorophosphate was used to extract curcumin from sample solutions with the aid of sonication. Optimum extraction efficiency was determined by examining extraction solvents, pH, centrifugation speed, time, sonication period, and temperature...
July 2, 2018: Journal of AOAC International
Frederik André Hansen, Drago Sticker, Jörg P Kutter, Nickolaj Jacob Petersen, Stig Pedersen-Bjergaard
This paper reports for the first time nanoliter-scale electromembrane extraction (nanoliter-scale EME) in a microfluidic device. Six basic drug substances (model analytes) were extracted from 70 μL samples of human whole blood, plasma, or urine, through a supported liquid membrane (SLM) of 2-nitrophenyl octyl ether (NPOE) and into 6 nL of 10 mM formic acid as acceptor solution. A DC potential of 15 V was applied across the SLM, and served as driving force for the extraction. The cathode was located in the acceptor solution...
July 2, 2018: Analytical Chemistry
Antonio Moreda-Piñeiro, Juan Sánchez-González, Sara Odoardi, Ana María Bermejo, Pilar Bermejo-Barrera, Francesco Saverio Romolo, Sabina Strano-Rossi
Synthetic cathinones are a type of drugs belonging to group of "new psychoactive substances" (NPSs). The illicit market of these substances is characterized by the continuous introduction in the market of new analogs to evade legislation and to avoid be detected. New screening and confirmation assays are therefore needed, mainly in forensic/clinical samples. In the current development a porous membrane protected - micro-solid-phase extraction (μ-SPE) has been developed for the assessment of several cathinones in urine...
July 1, 2018: Drug Testing and Analysis
Jesús Valimaña-Traverso, Sonia Morante-Zarcero, Damián Pérez-Quintanilla, María Ángeles García, Isabel Sierra, María Luisa Marina
Two novel materials based on periodic mesoporous organosilica (PMO) with cationic amine-bridged ligands, (styrylmethyl)bis(triethoxysilylpropyl)ammonium chloride (PMO-STPA) and bis(3-triethoxysilylpropyl)amine (PMO-TEPA), were synthesized in this work to obtain materials with reverse-phase/strong anionic exchange mixed-mode or strong anionic exchange retention mechanism, respectively. The resulting materials were comprehensively characterized and showed functionalization with cationic amine-bridged ligands, and values of surface areas characteristic of mesoporous materials (higher than 100 m2 /g)...
June 19, 2018: Journal of Chromatography. A
Abderrahmane Tighrine, Edgar Pinto, Armindo Melo, Isabel M P L V O Ferreira, Marzouk Mamou, Youcef Amir
> Background : Food additives are widely used in industries. Overall, these additives have a beneficial role, but if their concentration exceeds certain limits, they may have an adverse effect on human health. Objective : This study outlines the determination of benzoic acid (BA), sorbic acid (SA), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) in juices using dispersive liquid-liquid microextraction and HPLC-diode-array detection. Methods : Different parameters that significantly affect the extraction efficiency were optimized...
June 28, 2018: Journal of AOAC International
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