1,721,173 research outputs found
Synthesis and spectroscopic characterization of new organotin(IV) complexes with bis(3,5-dimethylpyrazol-1-yl)dithioacetate
No full textNew organotin(IV) derivatives containing the anionic ligand bis(3,5-dimethylpyrazolyl)dithioacetate [L2CS2] - have been synthesized by reaction of SnRnX4-n (R = Me, Ph, nBu or Cy; n = 1-3) acceptors and Li[L 2CS2]. Mononuclear complexes of the type [L 2CS2]RnSnCl4-n-1} have been obtained and fully characterized by elemental analyses and FT-IR in the solid state, and by NMR (1H and 119Sn) spectroscopy, conductivity measurements and electrospray ionization mass spectrometry (ESI-MS) in solution. ESI-MS spectra of methanol solutions of diorganotin derivatives, recorded with fragmentor potentials of 0, 50, 100 and 150 V, show the occurrence at 150 V of peaks attributable to the loss of the CS2 group from the ligands and the formation of stable tetraorganodistannoxane specie
Synthesis and solution studies by electrospray mass spectroscopy of new bis(imidazolyl)borate organotin(IV) complexes
No full textNew organotin(IV) derivatives containing the anionic dihydrobis(1-imidazolyl)borate [H2B(im)2]- have been synthesized from the reaction between SnRnX4-n (R = Me, Ph, nBu or Cy; n = 1-3) acceptors and [K{H2B(im)2}·(DMAC)] (DMAC = dimethylacetamide). Mono-nuclear complexes of the type {[H2B(im)2]RnSnCl4-n-1} have been obtained, which have been fully characterized by elemental analyses and FT-IR in the solid state and by NMR (1H and 119Sn) spectroscopy, conductivity measurements and electrospray ionization mass spectrometry (ESIMS) in solution. ESIMS spectra of a methanol solution of the complexes show the existence of hydrolysed species for mono- and di-organotin(IV) derivatives, while non-hydrolysed aggregates are detected for triorganotin(IV) derivative
Morphological, Histochemical and Phytochemical Investigation of the genus Hypericum of the Central Italy
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Determination of fourteen polyphenols in pulses by high performance liquid chromatography-diode array detection (HPLC-DAD) and correlation study with antioxidant activity and colour
No full textPulses, which include lentils, beans, chickpeas, peas, and soybeans, provide an important source of proteins, dietary fibers, minerals and vitamins, as well as such important bioactive molecules as polyphenols. The presence of polyphenols is often related to the colour of the pulse and to its antioxidant activity. The aim of this work was to set up a new HPLC-DAD method for simultaneously analysing 14 polyphenolic compounds, including two anthocyanins, in different varieties of pulses and to correlate the polyphenol content with the seed coat colour and the antioxidant activity. The total content of the analysed polyphenols ranged from 3 mg/kg for dehulled red lentils to 1630.5 mg/kg for ruviotto beans. Samples with dark testa (or seed coat), namely black lentils and diavoli beans, had higher antioxidant activity than those with pale testa, and a positive correlation was found between total phenolic content (TPC) and IC50 for dark coloured varieties
Utensile per la sterilizzazione della lancia vapore delle macchine da caffè
No full textUtensile per la sterilizzazione della lancia vapore delle macchine da caffè, caratterizzato per il fatto di consistere sostanzialmente in un bicchiere con pareti isolate termicamente, che risulta chiuso in sommità da una membrana in gomma dotata di un foro centrale e che reca un condotto di sfiato eseguito in corrispondenza delle sue pareti laterali al di sotto dell’anzidetta membrana
Giornata studio sulle tecniche preparative dei campioni analitici
No full textLa Microestrazione in fase solida (SPME):Cenni storici, introduzione alla tecnica di campionamento, suggerimenti ed applicazioni.
L'estrazione in fase solida (SPE): teoria, dispositivi e applicazioni
Reactions of anionic porphyrin with group 11 elements: a spectrophotometric and electrospray ionization mass spectrometry study
No full textThe reaction of 3,8,13,18-tetramethyl-21H,23H-porphine-2,7,12,17-tetrapropionic acid or coproporphyrin-I (CPI) with the elements of 11 group have been studied. CPI is an anionic porphyrin that slowly reacts with copper ion to form CuIICPI and with silver ions to form AgIICPI, AgIIICPI complexes and colloidal silver. Gold ions do not form complexes with CPI, but, in the main, colloidal gold and some CPI-N-oxide. The kinetics of the reactions with copper and silver were spectrophotometerically studied and the rate constants were calculated.
The identification and characterization of this water-soluble anionic porphyrin and its metal complexes have been performed by electrospray mass spectrometry (ESI-MS) that proved to be an excellent method for these determinations. The multiple charged parent ions for metal free ligand and their metal complexes were identified
Isofuranodiene is the main volatile constituent of Smyrnium perfoliatum L. subsp. perfoliatum growing in central Italy
No full textThe essential oil hydrodistilled from the aerial parts of Smyrnium perfoliatum subsp. perfoliatum growing in central Italy was analised by GC-MS. The main peak in the gas chromatogram was given by the furanosesquiterpene curzerene which is the Cope rearrangement product of isofuranodiene formed into injector and column during the gas chromatographic run. A truthful quantification of these compounds was achieved by HPLC-DAD analysis which showed that isofuranodiene is the main volatile component (180.0 mg/g eo) of S. perfoliatum subsp. perfoliatum, while curzerene occurs in small amounts (18.1 mg/g eo)
Qualitative characterization of a transesterification product of coconut oil by FIA-APCI-MS.
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Objectives The purpose of this work was the qualitative characterization of a recently transesterification product obtained from the coconut oil in the presence of polyglycerol-6 to produce a new PEG-free secondary surfactant. The purpose of a secondary surfactant is to reduce the harshness of a skin cleanser.
Methods The transesterification product was qualitatively characterized in our laboratory by flow injection analysis-atmospheric pressure chemical ionization-mass spectrometry (FIA-APCI-MS). The mass spectrum of the transesterification product was compared to those of the starting materials (polyglycerol and coconut oil).
Results The analyses highlighted the disappearance of the starting oil peaks and the appearance of new peaks assignable to the reaction products, mainly corresponding to diesters of polyglycerol. Additionally, peaks of unreacted polyglycerol are present as well as peaks of cyclization products derived from the polyglycerol starting material.
Conclusions The development of this fast and easy analytical method, requesting only few minutes to be performed, represents a very useful tool for the characterization of transesterification products during the quality control of batches under production.Resume
ObjectifsLe but de ce travail etait la caracterisation qualitative d'un produit de transesterification recemment obtenu a partir de l'huile de noix de coco en presence de polyglycerol-6 pour produire un nouveau tensioactif secondaire sans PEG, ce dernier generalement ajoute pour reduire l'agressivite d'un nettoyant pour la peau.
MethodesLe produit de transesterification a ete qualitativement caracterise dans notre laboratoire par Analyse du Debit d'injection - par Ionisation chimique a Pression atmospherique - par Spectrometrie de masse (FIA-APCI-MS). Le spectre de masse du produit de transesterification a ete compare a ceux des materiaux de depart (de polyglycerol et d'huile de noix de coco).
ResultatsLes analyses ont mis en evidence la disparition des pics d'huile de depart et l'apparition de nouveaux pics attribuables a des produits de reaction, correspondant principalement a des diesters de polyglycerol. De plus, les pics de polyglycerol non reagi sont presents ainsi que des pics de produits de cyclisation provenant de la matiere de depart de polyglycerol.
ConclusionsLe developpement de cette methode d'analyse rapide et facile represente un outil tres utile pour la caracterisation des produits de transesterification pendant le controle de la qualite des lots en production
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