Stable isotopes determination in some Romanian wines

This paper presents a study concerning the isotopic fingerprint (¹⁸O and ¹³C) of some wines prepared from relevant Romanian grape varieties (e.g. Feteasca Alba (FA), Feteasca Regala (FR) and Cabernet Sauvignon (CS)) obtained in different vintage years (2002, 2003, 2004, 2007 and 2008). These wines were obtained from different vineyards having a significant role in the wine market: Cotesti, Tohani, Stefanesti, Aiud, Cotnari, Bucium, Murfatlar, Bujoru, Dragasani and Valea Calugareasca. Several observations related to the dependence of isotope ratios on geographical origin and climatic conditions were drawn. The authentic wines obtained from the FA grape variety from six different vineyards showed δ¹⁸O values in the range of+3.28 (Cotesti region – 45 °38′N/27 °04′E) to?2.60 ‰ (Aiud region – 46 °19′N/23 °45′E). The δ¹³C values were very similar for all the samples with an average of about?26 ‰. The difference between the δ¹⁸O values was due to the different climatic zones, which have an influence on the δ¹⁸O values of wine water. For the wine variety CS obtained from the Dealu Mare–Tohani vineyard, production years 2003 and 2004, a greater difference in the δ¹⁸O values of wine water ranging from 1.89 (in 2004) to 5.35 ‰ (in 2003) was noted. This difference is explained by the different mean annual temperatures in 2003 and 2004.     

A Novel Label Free Electrochemical Magnetoimmunosensor for Human Interleukin‐6 Quantification in Serum

A novel magnetoimmunosensor, designed for sensitive and selective quantification of interleukin 6, is herein reported. The experimental design involves the covalent immobilization of anti‐interleukin 6 antibody through an amidic bond formed with the carboxyl functionalities provided at the surface of protein G‐functionalized magnetic microparticles, assuring a sandwich‐type immunoassay with electrochemical label free detection. All the experimental parameters involved in the elaboration and testing protocol were optimized. A linear calibration plot between the charge transfer resistance and the logarithmic concentration of interleukin‐6 was achieved in the 1 pg mL^?1 to 1 μg mL^?1 range. A limit of quantification of 1 pg mL^?1 and a detection limit of 0.3 pg mL^?1 were obtained. The optimized magnetoimmunosensor showed an excellent selectivity against some potentially interfering proteins and has been successfully applied for the determination of target protein in human serum, proving its clinical relevance.     

The need is compelling to perform an experiment capable of determining the velocity of gravitational interaction

In earlier papers some proposals were made concerning experiments that could lead to the determination of the velocity of the gravitational interaction. This paper points out that this determination can only be achieved by measuring the delayed gravitational field and not by measuring the propagation velocity of gravitational radiation, which remains a controversial problem, both theoretically and experimentally. The possibility is shown of the existence of a gravitational effect not unlike the Poynting-Robertson light effect and the importance is discussed of its determination for space and astronomical research. Some of the proposed mechanisms for explaining the gravitational interaction are reviewed and their nonviability is objectively pointed out. Finally, conclusions are drawn as to the necessity of carrying out experiments to determine the velocity of the gravitational interaction.     

Massenspektrometrische Untersuchungen von Isomeren Stickstoffverbindungen des Dibenzofurans

The mass spectra and the fragmentation patterns of amino-, acetamino- and nitrodibenzo-furan isomers have been investigated. Significant differences between the particular isomers are observed which are partly due to intramolecular hydrogen bond bridges, ortho effect or resonance stabilisation.     

Stable Isotope Fingerprinting for Pharmaceutical Authentication

ABSTRACT

The ¹³C stable isotopic composition of 38 pharmaceutical products was investigated for six medicine analgesics classes ibuprofen, diclofenac, paracetamol, metamizole, ketoprofene, and combinations containing paracetamol to evaluate differences between manufacturers and production batches. Complementary measurements were performed by inductively coupled plasma-mass spectrometry. Linear discriminant analysis was applied on experimental obtained data set for differentiation of three investigated drug types. The carbon isotopic compositions were between ?32.9 and ?22.6‰. The lowest values of ¹³C (mean of ?31.3‰) were obtained for metamizole from all six categories of investigated analgesics. The highest δ¹³C values were obtained for diclofenac (mean of ?25.9‰). The most accurate elemental predictors were V, Al, Sb, As, Pb, and Mn.     

Polyelectrolyte complexes. II. Specific aspects of the formation of polycation/dye/polyanion complexes

We report on the formation of the polycation/dye/polyanion (PC/D/PA) complexes by the interaction between nonstoichiometric polycation/dye (PC/D) complexes with polyanions. Polycations differed in their content of the (N,N‐dimethyl‐2‐hydroxypropylene ammonium chloride) units in the main chain. Poly(sodium acrylate) (NaPA), poly(sodium 2‐acrylamido‐2‐methylpropane sulfonate) (NaPAMPS) and poly(sodium styrenesulfonate) (NaPSS) were used as polyanions. Crystal Ponceau 6R (CP6R) and Ponceau 4R (P4R) with two or three sulfonic groups were used as anionic dyes. The interaction between nonstoichiometric PC/D complexes and polyanions was followed by UV‐VIS spectroscopy, viscometry, and conductometry measurements. Formation of PC/D/PA complexes takes place mainly by the electrostatic interaction between the polyanion and the free positive charges of the nonstoichiometric PC/D complex. The stoichiometry and the stability of the tricomponent complexes depended on the polycation structure, the structure and molecular weight of polyanion, the dye structure, and the P/D molar ratio. A high amount of the dye was excluded from the complex before the end point when a branched polycation was used. The higher the solubility of the dye the lower the stability of the PC/D/PA complexes. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 409–418, 1999     

Polyelectrolyte complexes. I. Synthesis and characterization of some insoluble polyanion-polycation complexes

The synthesis of some water-insoluble synthetic polyelectrolyte complexes formed between a weak polyanion and a strong polycation was followed. Sodium salts of poly(acrylic acid) and of some copolymers of acrylic acid with itaconic acid or maleic acid were used as anionic polymers. Cationic polyelectrolytes with quaternary ammonium salt groups in the main chain were used as strong polycations. The cationic polymers were different as concerns both the content of quaternary nitrogen atoms and the degree of branching. The complex formation was followed by the variation of the conductivity and of the specific viscosity of the reaction medium as well as by the turbidimetric titration versus the unit molar ratio polyanion/polycation. The deviation of the endpoint from stoichiometry was influenced mainly by the structure of the complementary polymers and by their molecular weights. The greater the structural differences, the higher the endpoint deviation from stoichiometry. Only insoluble polyelectrolyte complexes (PEC) were obtained in all the polyanion/polycation systems taken into account. The PECs were separated and characterized by elemental and spectral analyses as compared with the complementary polymers. © 1996 John Wiley & Sons, Inc.     

X-ray Structures of Pharmacologically Active 2-(3,5-Dimethyl-pyrazol-1-yl)-methylacetanilides

Abstract X-ray structures of three pharmacologically active lidocaine analogs, containing a common, substituted pyrazole moiety as the basic residue and variously substituted phenyl rings as the hydrophobic residue, have been determined. This isomeric series comprises 2-(3,5-dimethyl-pyrazol-1-yl)-2′-methylacetanilide (1), 2-(3,5-dimethyl-pyrazol-1-yl)-3′-methylacetanilide monohydrate (2), and 2-(3,5-dimethyl-pyrazol-1-yl)-4′-methylacetanilide (3). Crystal data are 1: space group P2 ₁ /c with a = 4.7617(2), b = 11.5638(4), c = 23.603(1) ?, β = 90.736(2)°, Z = 4; 2: P2 ₁ /c with a = 4.7260(1), b = 13.7001(4), c = 21.7006(6) ?, β = 93.425(1)°, Z = 4; 3: P2 ₁ /n with a = 6.4103(3), b = 24.584(1), c = 8.4449(4) ?, β = 100.273(3)°, Z = 4. In 1–3, the amide bond is trans-planar but the basic and hydrophobic residues adopt different orientations relative to this plane. Hydrogen bonding in 1 and 3 is based on C(4) linear arrays whereas in the monohydrate 2, the presence of water gives rise to R ₄ ⁴ (16) ring motifs. A summary of the local anesthetic and anti-arrhythmic properties of 1–3 is provided. Graphical abstract X-ray Structures of Pharmacologically Active 2-(3,5-Dimethyl-pyrazol-1-yl)-methylacetanilides Christina Zalaru, Mino R. Caira, Mircea Iovu, and Elena Cristea The title compounds are lidocaine analogs that display local anesthetic and anti-arrhythmic activities. X-ray analyses revealed a range of solid-state conformations among these isomeric compounds as well as variation in hydrogen bonding schemes, namely C(4) (R = o-, p-CH3) and R44(16) (R = m-CH3, monohydrate crystal). 1,1-Os3(CO)9(μ-CO)(phen)     

Screen-printed electrodes modified with HRP-zirconium alcoxide film for the development of a biosensor for acetaminophen detection

The development of a biosensor based on the immobilization of horseradish peroxidase (HRP) within a zirconium alkoxide-polyetilenimine film onto screen-printed electrodes (SPE) for acetaminophen detection and acetaminophen quantification in pharmaceutical products is described. The biosensor operation mode is based on monitoring the amperometric signal produced by the electrochemical reduction of the enzymatically generated electroactive oxidized species of acetaminophen in the presence of hydrogen peroxide. The enzyme immobilization is performed by retention in a polyethylenimine-zirconium alcoxide porous gel film, a technique that offers good entrapping and a protective environment for the biocomponent due to the hydration properties of the immobilization layer. SPEs have the advantage of being easily mass-produced at low costs with superior characteristics in comparison with classical electrode materials. In this configuration, zirconium alkoxide demonstrates its electrocatalytic activity. The biosensor allows the quantification of acetaminophen with a limit of detection of 6.21×10^?8 M and a linear range between 4.35×10^?7 M and 4.98×10^?6 M. Finally, the biosensor is applied to the quantitative analysis of acetaminophen in Perdolan® tablets.

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Guanidination chemistry for qualitative and quantitative proteomics

The application of guanidination chemistry, the conversion of lysine into homoarginine residues, is used to illustrate several important general considerations relating to the use of differential isotope labelling for relative quantification in proteomics. The derivatisation procedure has been optimised for automation using a liquid handling station designed for proteomics. Automated application of the procedure to the analysis of in-gel tryptic digests of multiple spots from the two-dimensional gel electrophoretic (2DE) analysis of proteins from the FDCP-mix cell line shows near-universal improvement in protein identification as a result of derivatisation. This chemistry has been extended for relative quantification, applicable to matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS) and also tandem mass spectrometry (MS/MS). It provides a robust method for the quantitative comparison of two samples that have been separated by 2DE. A peptide pair may display poor detection during MS analysis, causing their reliable relative quantification to be difficult. In such circumstances, the additional selectivity of detection provided by MS/MS can substantiate identification and allow relative quantification of these species via product ion signal ratios.