Identification of anthocyanins in plant sources and textiles by surface‐enhanced Raman spectroscopy (SERS)

The aim of the present study was to provide experimental procedures for the identification of anthocyanin‐based dyes used in antiquity. In particular, we assessed the possibility to identify anthocyanins, both in plant extracts and in dyed textiles, by means of surface‐enhanced Raman spectroscopy (SERS), a very chemically specific technique that is moreover sensitive to the changes in structures of molecules, phenomena that occur extensively in the chemistry of anthocyanins. The choice of the plant sources (bilberry, elderberry, sumac, purple corn and hollyhock) was based on their attested use in history as dyeing matters. Suitable extraction and pre‐treatment procedures were optimized both for plant sources (berries, cob glumes and flowers) and textiles dyed with such sources in the laboratory, followed by SERS analyses at different pH values. Finally, special attention was paid to the well‐known instability of anthocyanins: dyed wool samples were exposed to artificial aging in order to verify the possibility to identify such molecules also in faded textiles. The achievement of reliable surface‐enhanced Raman spectra from these samples encourages us to suggest the protocol for the analysis of historical objects. Copyright © 2015 John Wiley & Sons, Ltd.     

Single and Dual-Domain Models to Evaluate the Effects of Preferential Flow Paths in Alluvial Sediments

Typical features of preferential flow paths were evidenced by numerical tests of convective transport of conservative solutes performed in three blocks of alluvial sediments at the scale of depositional elements. The numerical experiments are analysed with standard single-domain models (SDMs) and with dual-domain models (DDMs): the model parameters are identified by minimisation of the misfit between the ??experimental?? and the modelled cumulative breakthrough curves (BTCs) and between the ??experimental?? and the modelled temporal moments of the BTCs. The results for the SDMs show different behaviours for the three model blocks and for the different flow directions, in good agreement with their hydrostratigraphic characteristics. The results for the DDMs sometimes correspond to cases for which one of the two domains is dominant and its values of diffusivity and average velocity are close to those obtained for the SDM; in some cases the DDM performs much better than the SDM and correctly represents the effects of preferential flow paths. Finally the relevance of the DDM is analysed in the framework of multi-objective optimisation: a proper choice of the objective-functions yields Pareto sets whose geometries are different for single- and dual-domain media.     

UHPLC-DAD method for the determination of neonicotinoid insecticides in single bees and its relevance in honeybee colony loss investigations

In the understanding of colony loss phenomena, a worldwide crisis of honeybee colonies which has serious consequences for both apiculture and bee-pollination-dependent farm production, analytical chemistry can play an important role. For instance, rapid and accurate analytical procedures are currently required to better assess the effects of neonicotinoid insecticides on honeybee health. Since their introduction in agriculture, neonicotinoid insecticides have been blamed for being highly toxic to honeybees, possibly at the nanogram per bee level or lower. As a consequence, most of the analytical methods recently optimized have focused on the analysis of ultratraces of neonicotinoids using liquid chromatography–mass spectrometry techniques to study the effects of sublethal doses. However, recent evidences on two novel routes—seedling guttations and seed coating particulate, both associated with corn crops—that may expose honeybees to huge amounts of neonicotinoids in the field, with instantly lethal effects, suggest that selected procedures need optimizing. In the present work, a simplified ultra-high-performance liquid chromatography–diode-array detection method for the determination of neonicotinoids in single bees has been optimized and validated. The method ensures good selectivity, good accuracy, and adequate detection limits, which make it suitable for the purpose, while maintaining its ability to evaluate exposure variability of individual bees. It has been successfully applied to the analysis of bees in free flight over an experimental sowing field, with the bees therefore being exposed to seed coating particulate released by the pneumatic drilling machine.     

Traceability in Multi-ingredient Botanicals by HPTLC Fingerprint Approach

JPC – Journal of Planar Chromatography – Modern TLC - A high-performance thin-layer chromatography (HPTLC) method was developed for simple and rapid chemical analyses of...     

Generation of Highly Resilient to Decoherence Macroscopic Quantum Superpositions via Phase-covariant Quantum Cloning

In this paper we analyze the resilience to decoherence of the Macroscopic Quantum Superpositions (MQS) generated by optimal phase-covariant quantum cloning according to two coherence criteria, both based on the concept of Bures distance in Hilbert spaces. We show that all MQS generated by this system are characterized by a high resilience to decoherence processes. This analysis is supported by the results of recent MQS experiments of N=3.5×10⁴ particles.     

A new terpyridine tethered polythiophene: Electrosynthesis and characterization

A novel polythiophene bearing a pendant terpyridine moiety has been synthesized by electrochemical polymerization of a new thiophene monomer, namely 4′‐(2,2′:5′,2″‐terthien‐3′‐ethynyl)‐2,2′:6′,2″‐terpyridine (TAT). The insertion of a conjugated ethynyl spacer between the terthiophene and the terpyridine fragments provides for an effective extension of the delocalization of electrons within the structural unit and the polymer as a whole. The synthesis and characterization of the relevant monomer, the electrosynthesis of the corresponding polymer and its electrochemical, UV–visible spectroelectrochemical and IR characterization are described. Finally, a comparison between the electrochemical, spectroscopic, and spectroelectrochemical properties of PTAT and the analogue, saturated‐spacer PTTT (TTT = 4′‐[(2,2′:5′,2″‐terthien‐3′‐yl)methoxy]‐2,2′:6′,2″‐terpyridine) polymer is discussed. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011