0000000000005135
AUTHOR
Juan Peris-vicente
Use of linear discriminant analysis applied to vibrational spectroscopy data to characterize commercial varnishes employed for art purposes.
An improvement of methodologies for characterising synthetic resins used in varnishes employed for art purposes has been suggested. Several kinds of standard of the most common polymeric resins (acrylic, vinyl, poly(vinyl alcohol), alkyd, cellulose nitrate, latex, polyester, polyurethane, epoxy, organosilicic, and ketonic) were analyzed by Fourier transform infrared (FTIR) spectroscopy. Synthetic resins characterization is based on the mathematical treatment of their whole spectrum, dividing it in 13 sections, avoiding the one-by-one interpretation of the absorption bands. The mathematical model takes as variables the maximal absorbance of each section, and each synthetic standard resin as …
Micellar liquid chromatography determination of rivaroxaban in plasma and urine. Validation and theoretical aspects.
A Micellar Chromatographic method to determine rivaroxaban in plasma and urine has been developed. The samples were dissolved in the mobile phase (SDS 0.05 M – 1-propanol 12.5%, phosphate buffered at pH 7) and 20 μL directly injected, avoiding the extraction and purification steps. Using a C18 column and running under isocratic mode at 1 mL/min, analyte was eluted without interference from the matrix in <6.0 min. The detection absorbance wavelength was set to 250 nm. The procedure was validated by Food and Drug Administration guidelines in terms of: system suitability, calibration range (0.05–5 mg/L), linearity, sensitivity, robustness, carry-over effect, specificity, accuracy (−11.1 to 4.2…
Development and validation of a micellar liquid chromatographic method to determine three antitumorals in plasma
Aim: A micellar liquid chromatographic method to determine several anticancer drugs (pazopanib, dabrafenib and regorafenib) in plasma was developed and validated by the guidelines of the EMA. Experimental: Plasma samples were directly injected, after a 1/5-dilution in a micellar solution. The drugs were resolved in <18 min using a C18 column. The mobile phase was an aqueous solution of 0.12 M SDS – 2% 1-pentanol, buffered at pH 7. The detection was performed by absorbance at 260 nm. Results: The values of the main validation parameters were: LOD (0.1–1 mg/l), calibration range (0.2–2 to 80 mg/l), accuracy (-12.5 to +11.7%) and precision (<11.9%). Conclusion: The procedure was conduct…
Archaeometrical study of paleometallurgical materials from the archaeological site “Cerro de las Balsas — Chinchorro” (La Albufereta, Alacant, Spain)
An Iberian archaeological site located in the east of Spain is one of the most important cupellation centers found in the 4th century b.c. Different metallurgical materials were found in the archaeological site as minerals, cast slags, forged slags, metallic lead, cupella fragments and bronzes. Also was found reverbs remains used for cupper-based materials and cupellation procedure, and hearth forge remains for obtained iron material. The recuperated samples were studied by comparing samples of the same type of material by macroanalysis and microanalysis. The microanalysis and quantitation of the different archaeological materials was carried out by SEM/EDX. The information provides about t…
Procedure for the Screening of Eggs and Egg Products to Detect Oxolonic Acid, Ciprofloxacin, Enrofloxacin, and Sarafloxacin Using Micellar Liquid Chromatography
A method based on micellar liquid chromatography was developed to determine oxolinic acid, ciprofloxacin, enrofloxacin, and sarafloxacin in eggs and egg products. The antimicrobial drugs were obtained in a micellar solution which was directly injected. The analytes were resolved using a C18 column and a mobile phase of 0.05 M sodium dodecyl sulfate—7.5% 1-propanol—0.5% triethylamine, buffered at pH 3 with phosphate salt, running under the isocratic mode. The signal was monitored by fluorescence. Validation was successfully performed according to the EU Commission Decision 2002/657/EC in terms of specificity, calibration range (LOQ to 1 mg/kg), linearity (R2 >
Thermal decomposition of chromite spinel with chlorite admixture
Abstract The behaviour of minerals in a South African chromite ore during the increasing of the temperature has been studied. Firstly, the changes produced during the ignition process have been examined by means of thermal and differential analysis (TGA–DTA) until 1200 °C. The characterization of the initial mineral and those obtained after heating at several temperatures in room atmosphere has been performed by X-ray diffraction (XRD). Moreover, voltammetric analyses have allowed to determine the variation of the iron oxidation degree in the studied materials. Light microscopy was applied to find more information about the different phases by their colour. During the heating, a wide range …
Electrochemical characterization of solid state reaction kinetics using voltammetry of microparticles. Application to thermal decomposition of iron chromites
The voltammetry of microparticles is applied to characterize the electrocatalytic ability of solids towards selected electrochemical processes. The variation of catalytic currents under fixed electrochemical conditions permits to obtain composition/time data to be fitted with solid state kinetic models. This methodology is applied to analyze the thermal decomposition of magnesiochromite ferroan and chlorite chromian standards and a South Africa iron chromite ore on the basis of the significant catalytic effect on the electrochemical oxygen evolution reaction (OER) in aqueous alkaline media at mineral-modified graphite electrodes. Measurement of the time variation of catalytic current for OE…
Quantification of rifampicin and rifabutin in plasma of tuberculosis patients by micellar liquid chromatography
A Micellar Liquid Chromatographic method is described to determine Rifampicin and Rifabutin in plasma from Tuberculosis patients. Samples were diluted in mobile phase and then directly injected, avoiding long and tedious extraction steps. The analytes were resolved from the matrix without interferences from endogenous compounds using a mobile phase of sodium dodecyl sulfate 0.15 mol L-1–6%(v/v) 1-pentanol and phosphate buffer at pH 3, running at 1 mL min−1 through a C18 column at 25 °C. Detection was carried out by UV absorbance at 270 nm. Under these conditions, the final chromatographic analysis time was 22 min. The analytical methodology was validated following the FDA 2018 Bioanalytical…
Direct infusion mass spectrometry as a fingerprint of protein-binding media used in works of art
A direct infusion mass spectrometry method for the characterization of proteinaceous glues from binding media used in pictorial works of art prior to conservation or restoration treatment is proposed. Amino acids are released by acid hydrolysis and dissolved in a mixture of acidic water and ethanol. This mixture is directly infused into a mass spectrometer without any derivatization. The mass spectrometer is operated in positive ion electrospray mode (ESI-MS) to yield [M+H]+ ions for the amino acids. Relative amounts of each amino acid are calculated for each protein (beef and porcine gelatines, albumin, casein and egg). The analyzed proteins were satisfactorily distinguished. The method is…
COMPARISON OF THE COURSE SYLLABUS OF THE THEORY SUBJECT "CHEMISTRY" IN CHEMISTRY GRADE AND IN ENGINEERING STUDIES
Comunicació presentada a INTED2016, 10th International Technology, Education and Development Conference. (March 7-9, 2016, Valencia, Spain). The aim of the chemistry-related subjects, taught in the first academic year of several grades at the University Jaume I, is to provide a broad overview about general chemistry. However, these defined subjects are adapted to the structure, objectives and curricula of each grade. In this paper, a comparison of the course syllabus of the Chemistry subjects taught in the "Chemistry grade" and in several "Engineering grades" (Agricultural, Mechanical, Electrical, Industrial Technology and Chemical) is detailed. The differences and similarities of the subje…
Development of a method to determine axitinib, lapatinib and afatinib in plasma by micellar liquid chromatography and validation by the European Medicines Agency guidelines
A method based on micellar liquid chromatography to quantify the tyrosine kinase inhibitors axitinib, lapatinib and afatinib in plasma is reported. The sample pretreatment was a simple 1/5-dilution in a pure micellar solution, filtration and direct injection, without requiring extraction or purification steps. The three drugs were resolved from the matrix in 17 min, using an aqueous solution of 0.07 M sodium dodecyl sulfate – 6.0% 1-pentanol, buffered at pH 7 with 0.01 M phosphate salt as mobile phase, running under isocratic mode at 1 mL/min through a C18 column. The detection was performed by absorbance at 260 nm. An accurate mathematical relationship was established between the retention…
Use of Micellar Liquid Chromatography to Determine Mebendazole in Dairy Products and Breeding Waste from Bovine Animals
Mebendazole is an anthelmintic drug used in cattle production. However, residues may occur in produced food and in excretions, jeopardizing population health. A method based on micellar liquid chromatography (MLC) was developed to determine mebendazole in dairy products (milk, cheese, butter, and curd) and nitrogenous waste (urine and dung) from bovine animals. Sample treatment was expedited to simple dilution or solid-to-liquid extraction, followed by filtration and direct injection of the obtained solution. The analyte was resolved from matrix compounds in less than 8 min, using a C18 column and a mobile phase made up of 0.15 M sodium dodecyl sulfate (SDS)&ndash
Characterization of proteinaceous glues in old paintings by separation of the o-phtalaldehyde derivatives of their amino acids by liquid chromatography with fluorescence detection.
A HPLC-fluorescence method for characterization of proteinaceous glues from binding media used in pictorial works of art prior to conservation or restoration treatment is proposed. Fluorescence derivatization of amino acids released by acid hydrolysis of standard proteins is studied. The derivatization reagent was o-phtalaldehyde with 2-mercaptoethanol as catalyst. Mobile phase was a programmed gradient among two eluents (water buffered at pH 5.8 wit 5% THF, and methanol) and is able to satisfactorily resolve the amino acid derivatives in 45min. Peak area ratios among amino acid derivatives and the leucine derivative are useful to characterize the proteins. The method shows good sensitivity…
Characterization of commercial synthetic resins by pyrolysis-gas chromatography/mass spectrometry: application to modern art and conservation.
To characterize a set of synthetic resins, a methodology by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) has been developed. The studied reference materials were commercial versions of a wide range of synthetic resins. For each polymer, the pyrolytic and chromatographic conditions were optimized to adequately resolve the fragment mixture in a short time. The proposed analytical method does not require previous treatment of the sample, and due to its high sensitivity, only a small sample quantity in the microgram range can be used. The pyrolysis temperature was found to have little effect on the obtained pyrograms. The summarized data set for the individual polymer materials, es…
Determination of isoniazid and pyridoxine in plasma sample of tuberculosis patients by micellar liquid chromatography
It is no doubt Isoniazid is a powerful tuberculosis drug, but it might give rise to Vitamin B6 (Pyridoxine) deficiency. In this case, a usual treatment is the combined administration of Isoniazid and Pyridoxine. An easy-to-conduct procedure based on Micellar Liquid Chromatography has been developed to quantify Isoniazid and Pyridoxine in plasma from Tuberculosis patients. The sample was diluted in mobile phase, filtered and directly injected, thus avoiding extraction or purification steps. Both drugs were adequately resolved from the matrix and endogenous compounds using a mobile phase made up of 0.15 M sodium dodecyl sulfate – 8%(v/v) 1-butanol – 0.01 M phosphate buffer at pH 3, running at…
Analytical and mineralogical studies of ore and impurities from a chromite mineral using X-ray analysis, electrochemical and microscopy techniques
A wide analytical study of South African chromite ore, material with high interest in ceramic industry, has been carried out. With this purpose, an accurate chemical identification and mineralogical characterization of the mineral and the gangue have been performed using X-ray fluorescence (XRF), voltammetry, X-ray diffraction (XRD), light microscopy (LM), and scanning electron microscopy (SEM/EDX). The elemental composition of the sample (ore and gangue) has been obtained by XRF. The voltammetric analysis has allowed to demonstrate that iron in the sample was as Fe(II). The main compound of the chromite ore was a spinel (magnesiochromite ferroan), identified by XRD from the sample, which c…
Gas chromatography/mass spectrometry characterization of historical varnishes of ancient Italian lutes and violin
The organic constituents of historical vanishes from two ancient Italian lutes and a Stradivari violin, kept in the Musée de la musique in Paris, have been characterized using gas chromatography-mass spectrometry. Results have been compared with the chromatograms and mass spectra of recent as well as old naturally aged reference materials. The three historical varnishes analyzed have been shown to be oil varnishes, probably mixtures of linseed oil with resins. Identification of diterpenoids and triterpenoids compounds, and of the resins that may have been ingredients of the varnishes, are discussed in this paper.
Characterization of waxes used in pictorial artworks according to their relative amount of fatty acids and hydrocarbons by gas chromatography.
A study attempted to characterize natural waxes used in pictorial works of art was carried out by means of gas chromatography. The analytical treatment requires prior hydrolysis of the waxes to release the fatty acids (FA) (myristic (myr), palmitic (pal), oleic (ole), stearic (ste), araquidic (ara), behenic (beh), lignoceric (lig), cerotic (cer)) from the main esters of the waxes. The formation of volatile derivatives of the fatty acids was carried out by derivatization with ethyl choroformate (ECF). This derivatization reagent was chosen due to the speed, safety and quantitativity of the reaction. The analyzed hydrocarbons were n-eicosane, n-heneicosane, n-docosane, n-tricosane, n-tetracos…
Analytical Study of a Resinous Material Used as Sealing in Ancient Pottery Found in an Archaeological Site by Thermally Assisted Hydrolysis Methylation–Gas Chromatography–Mass Spectrometry, Vibrational Spectroscopy and Light Microscopy
Abstract A resin sample was found in the archaeological site of Lixus (Morocco), belonging to the second century BC. The resinous material was found inside an amphora containing iron remains used in the plug as sealing material to hermetically close the pottery. The resinous sample was studied by several analytical techniques, as thermally assisted hydrolysis and methylation–gas chromatography–mass spectrometry (THM–GC–MS), Fourier transformed infrared spectroscopy (FTIR), and light microscopy. The material was identified as a Pinaceae resin. Therefore, a modern pine resin was also analyzed to consider the influence of aging in the archaeological sample. The ancient material was found not t…
Determination of albendazole and ivermectin residues in cattle and poultry-derived samples from India by micellar liquid chromatography
We have developed a method, based on micellar liquid chromatography, to determine albendazole and ivermectin in dairy products and biological waste from bovine, as well as edible tissues from poultry. Anthelmitics were resolved in less than 10 min using a C18 column and a mobile phase of 0.15 mol/L sodium dodecyl sulfate – 6% 1-pentanol at buffered at pH 7 with a 0.01 M phosphate salt, running under isocratic mode at 1 mL/min. Detection was by absorbance at 292 nm. Method was successfully validated following official validation guidelines, in terms of: selectivity, sensitivity, calibration range (0.0125−0.5 mg/kg to 25−50 mg/kg), linearity (r2 > 9990), trueness (86.3–105.6%), precision (<12…
Screening of some banned aromatic amines in textile products from Indian bandhani and gamthi fabric and in human sweat using micellar liquid chromatography
Certain dyes in textile products, which are capable of reductively splitting into carcinogenic aromatic amines, are strictly controlled in many countries. A simple, rapid, sensitive and green chromatographic method has been developed and validated for the simultaneous determination of 4-aminophenol (4-AMP), p-phenylenediamine (p-PPD) and benzidine (BNZ), banned aromatic amines in dyeing clothes and human sweat. The separation was achieved using a micellar mobile phase of 0.1 M SDS, 4% 1- butanol (v/v) buffered to pH 7 with sodium dihydrogen phosphate, flowing under isocratic mode at 1 mL/min through a C18 column. Photodiode array detector was set at 210 nm. Using the above chromatographic c…
Comparison of different analytical processes for patulin determination in apple juice
F. M. Valle-Algarra, R. Mateo, A. Medina, F. Mateo, E. M. Mateo, E. Sanchis Blanco, J.V. Gimeno-Adelantado, J. Peris-Vicente and M. Jimenez 1 Dpto. de Quimica Analitica, Facultad de Quimica, Universidad de Valencia, Dr. Moliner 50, E-46100 Burjassot, Valencia, Spain 2 Dpto. de Microbiologia y Ecologia, Facultad de Biologia, Universidad de Valencia, Dr. Moliner 50, E-46100 Burjassot, Valencia, Spain 3 Dpto. de Ingenieria Electronica, Universidad Politecnica de Valencia, Camino de Vera 14, E-46022, Valencia, Spain
Infusion mass spectrometry as a fingerprint to characterize varnishes in oil pictorial artworks.
Mass spectrometry methodology to characterize drying oil used as binding media and varnishes in pictorial artworks, prior to conservation or restoration treatment, is proposed. The analytical treatment requires prior basic hydrolysis of the samples to release the fatty acids : caprylic, pelargonic, capric, sebacic, azelaic, suberic, eicosanoic, lauric, mirystic, palmitic, linolenic, linoleic, oleic and stearic, followed by separation from the matrix by a hexane/water extraction. After removing the solvent, the remaining solid is dissolved in potassium hydroxide, propanol and methanol. The mixture is directly infused into a mass spectrometer without any previous derivatization or separation …
Archaeopolymetallurgical study of materials from an Iberian culture site in Spain by scanning electron microscopy with X-ray microanalysis, chemometrics and image analysis
Abstract Archaeometallurgical materials from “La Bastida de Moixent”, a site in Valencia (Spain), from the second Iberian iron age (4th Century B.C.) have been studied using metallographic techniques, microanalysis, chemometrics and image analysis. The materials come from various phases of iron production and cupellation of argentiferous lead to obtain silver. Scanning electron microscopy (SEM) is used to determine the morphological, microstructural and topographic characteristics of the samples. Image analysis was used to obtain a numeric estimate of the main components in these materials. X-ray microanalysis (SEM/EDX) provides qualitative and quantitative information about the elements in…
Simultaneous detection of hazardous skin whitening agents in Indian cosmetic products using a green chromatographic technique
The present work mainly highlights the simultaneous detection of four skin whitening agents i.e. hydroquinone (HQ), resorcinol (RS), catechol (CC) and 3,3′-dichlorobenzidine (DCB) in facial creams and body lotion. Among these, the first three are positional isomers of dihydroxybenzene so simultaneous separation is difficult with the conventional reverse-phase high-performance liquid chromatographic technique (RP-HPLC). The selected skin whitening agents were detected in facial cream and body lotion using micellar liquid chromatography coupled to a photodiode array detector (MLC-PDA). In the present study, optimization of the method was accomplished using response surface methodology (RSM) w…