Grupo: Control Analítico Ambiental, Bioquímico y Alimentario (FQM297)
https://hdl.handle.net/10481/28453
2024-03-28T18:45:20ZNew fluorescent pH sensors based on covalently linkable PET rhodamines
https://hdl.handle.net/10481/63199
New fluorescent pH sensors based on covalently linkable PET rhodamines
Aigner, Daniel; Borisov, Sergey M.; Orriach Fernández, Francisco José; Fernández Sánchez, Jorge Fernando; Saf, Robert; Klimant, Ingo
A new class of rhodamines for the application as indicator dyes in fluorescent pH sensors is presented. Their pH-sensitivity derives from photoinduced electron transfer between non-protonated amino groups and the excited chromophore which results in effective fluorescence quenching at increasing pH. The new indicator class carries a pentafluorophenyl group at the 9-position of the xanthene core where other rhodamines bear 2-carboxyphenyl substituents instead. The pentafluorophenyl group is used for covalent coupling to sensor matrices by “click” reaction with mercapto groups. Photophysical properties are similar to “classical” rhodamines carrying 2′-carboxy groups. pH sensors have been prepared with two different matrix materials, silica gel and poly(2-hydroxyethylmethacrylate). Both sensors show high luminescence brightness (absolute fluorescence quantum yield ΦF≈0.6) and high pH-sensitivity at pH 5–7 which makes them suitable for monitoring biotechnological samples. To underline practical applicability, a dually lifetime referenced sensor containing Cr(III)-doped Al2O3 as reference material is presented.
Financial support from the Austrian Science Fund FWF (Project no. P 21192-N17) and from the Spanish Ministry of Education (Joint Project no. AT2009-0019) is gratefully acknowledged. The authors thank the Institute of Organic Chemistry, Graz University of Technology, particularly Jana Rentner, MSc for kind support in performing LC-MS. Furthermore, we thank Johann Pichler, Institute of Inorganic Chemistry, Graz University of Technology, for acquiring 19F-NMR spectra, as well as Sarah Schiller and Stefan Schobesberger.
Comparative characterization of phenolic and other polar compounds in Spanish melon cultivars by using high-performance liquid chromatography coupled to electrospray ionization quadrupole-time of flight mass spectrometry
https://hdl.handle.net/10481/28512
Comparative characterization of phenolic and other polar compounds in Spanish melon cultivars by using high-performance liquid chromatography coupled to electrospray ionization quadrupole-time of flight mass spectrometry
Rodríguez Pérez, Celia; Quirantes-Piné, Rosa; Segura Carretero, Antonio; Fernández Gutiérrez, Alberto
Melon (Cucumis melo L.), belonging to the Cucurbitaceae family, is a significant source of phytochemicals which provide human health benefits. High-performance liquid chromatography coupled to electrospray ionization mass spectrometry quadropole-time of flight (HPLC-ESIQTOF-MS) was used for the comprehensive characterization of 14 extracts from 3 Spanish varieties of melon (Galia, Cantaloupe, and Piel de Sapo). A total of 56 different compounds were tentatively identified, including: amino acids and derivatives, nucleosides, organic acids,
phenolic acids and derivatives, esters, flavonoids, lignans, and other polar compounds. Of these, 25 were tentatively characterized for the first time in C. melo varieties. Principalcomponent analysis (PCA) was applied to gain an overview of the distribution of the melon varieties and to clearly separate the different varieties. The result of the PCA for the negative mode was evaluated. The variables most decisive to discriminate among varieties included 12 of the metabolites tentatively identified.