12 documents found, page 1 of 2
Photochemical oxidation of polyethylene terephthalate microplastics adsorbed on...
Q. V. da Costa, Camila; Nobahar, Amir; Egea-Corbacho, Agata; Jockusch, Steffen; Power, Deborah Mary; Ramamurthy, Vaidhyanathan; Silva, José Paulo daThe environmental contamination by plastics, microplastics, and related compounds is a major concern. While the detection and release of micro- and nanoparticles from these materials have been widely studied, the formation and release of molecules resulting from their degradation in the environment have been overlooked. This work presents a study of the products released from poly(ethylene terephthalate) (PET) ...
Fluorescence sensing of microplastics on surfaces
Costa, Camila Q. V.; Cruz, Joana; Martins, Jorge; Teodosio, Maria; Jockusch, Steffen; Ramamurthy, V.; Da Silva, José PauloMicroplastics, nanoplastics and related products have been recently found in marine ecosystems worldwide, calling for new analytical methods for rapid detection and risk assessment. Fluorescence is a sensitive technique that when used with polarity probes can potentially detect low-polarity plastic particles in environments. Here, we evaluated the fuorescence technique to sense polystyrene microparticles direct...
Quantitative analysis of biogenic polyamines in distilled drinks by direct elec...
Galego, Ludovina; Rodrigues, Maria A. A.; Mendes, Débora C.; Jockusch, Steffen; Silva, José P. daRATIONALE: Biogenic polyamines in drinks have been implicated in undesirable physiological effects. Methods for their detection and quantification usually involve derivatization, pre-concentration and clean-up. To assist the evaluation of the potential risk of distillates, it was important to develop a simple and fast analytical method, which is described in this study.METHODS: Biogenic polyamines were selectiv...
Synthetic versus natural receptors: supramolecular control of chemical sensing ...
Silva, José P. da; Choudhury, Rajib; Porel, Mintu; Pischel, Uwe; Jockusch, Steffen; Hubbard, Peter; Ramamurthy, Vaidhyanathan; Canario, Adelino V. M.The encapsulation of odorants by the synthetic receptor cucurbit[7]uril (CB[7]) reduces the response of olfactory receptors in Mozambique tilapia (Oreochromis mossambicus) in vivo. For example, the olfactory receptor response to the odorant adamantan-1-amine, as measured by electro-olfactography, was suppressed by 92% in the presence of CB[7]. A reduction in olfactory response of 88% was observed for pentane-1,...
Benzoin type photoinitiator for free radical polymerization
Esen, Duygu Sevinc; Arsu, Nergis; Silva, José P. da; Jockusch, Steffen; Turro, Nicholas J.Benzoin, a popular photoinitiator for free radical polymerization of vinyl monomers, was improved by introduction of two methyl thioether substituents. This new benzoin derivative showed an about 50 times higher light absorption in the near-UV spectral region and performed better than the unsubstituted benzoin in polymerization experiments in bulk solutions or films of acrylate monomers when low initiator conce...
Polyphenol and volatile profiles of pomegranate (Punica granatum L.) fruit extr...
Galego, Ludovina; Jockusch, Steffen; Silva, José P. daThis work reports on the preparation of new aromatic pomegranate liquors by maceration of pomegranate juice and arils in Arbutus unedo L. distillate. The volatile, anthocyanin and ellagitannin profiles were monitored after each step. Aromatic compounds of pomegranates, such as limonene, 1-hexenol and trans-caryophyllene, were detected in trace levels and showed little contribution to the liquor aroma. The main ...
Capsular complexes of nonpolar guests with octa amine host detected in the gas ...
Silva, José P. da; Kulasekharan, Revathy; Cordeiro, Carlos; Jockusch, Steffen; Turro, Nicholas J.; Ramamurthy, V.Nanocapsules, made up of the deep cavitand octa amine and several guests, were prepared in aqueous acidic solution and were found to be stable in the gas phase as detected by electrospray ionization mass spectrometry (ESI-MS). The observed gas phase host-guest complexes contained five positive charges and were associated with several acid molecules (HCI or HBr).
Aggregates of cucurbituril complexes in the gas phase
Silva, José P. da; Jayaraj, Nithyanandhan; Jockusch, Steffen; Turro, Nicholas J.; Ramamurthy, V.The self-organization of cucurbit[n]uril (n = 7 and 8, CBs) complexes was probed by electrospray mass spectrometry. The self-association of CB complexes is a general phenomenon but shows some dependence on the absence, presence, and type of included guest molecules.
Supramolecular photocatalysis: insights into cucurbit[8]uril catalyzed photodim...
Pemberton, Barry C.; Singh, Raushan K.; Johnson, Alexander C.; Jockusch, Steffen; Silva, José P. da; Ugrinov, Angel; Turro, Nicholas J.Guest induced shape change of the cucurbit[8]uril cavity is likely rate limiting in the supramolecular photocatalytic cycle for CB8 mediated photodimerization of 6-methylcoumarin.
Photochemistry of 4-chlorophenol and 4-chloroanisole adsorbed on MFI zeolites: ...
Silva, José P. da; Jockusch, Steffen; Martinho, José M. G.; Ottaviani, M. Francesca; Turro, Nicholas J.The phototransformation of aryl chlorides adsorbed on MFI zeolites is markedly different from that observed in solution and other solid surfaces such as silica. The formation of radical cations and the constraints imposed by the channels shift the reactivity from the C-CI bond to the O-R bond. Irradiation generates kinetically stabilized intermediates that can be characterized using conventional steady-state sp...