ORCID Profile
0000-0002-6032-8679
Current Organisation
NOVA University Lisbon, NOVA School of Science and Technology
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Publisher: Elsevier BV
Date: 15-05-2007
DOI: 10.1016/J.TALANTA.2006.12.040
Abstract: Two advanced oxidation processes (AOPs), based on high-intensity focused ultrasound (HIFU), namely, KMnO(4)/HCl/HIFU and H(2)O(2)/HCl/HIFU are studied and compared for the determination of toxic arsenic in human urine [As(III)+As(V)+MMA+DMA] by flow-injection hydride-generation atomic absorption spectrometry (FI-HG-AAS). The KMnO(4)/HCl/HIFU procedure was found to be adequate for organic matter degradation in human urine. l-cysteine (letra minuscula) was used for As reduction to the trivalent state. The new procedure was assessed with seven urines certified in different As species. Results revealed that with KMnO(4)/HCl/HIFU plus l-cysteine the toxic arsenic can be accurately measured in human urine whilst the H(2)O(2)/HCl/HIFU procedure underestimates toxic As. DMA and MMA degradation in urine were observed, due to the effects of the ultrasonic field. Recoveries for As(III), As(V), MMA and DMA were within the certified ranges. Arsenobetaine was not degraded by the AOPs. The new procedure adheres well to the principles of analytical minimalism: (i) low reagent consumption, (ii) low reagent concentration, (iii) low waste production and (iv) low amount of time required for s le preparation and analysis.
Publisher: Elsevier BV
Date: 04-2014
DOI: 10.1016/J.TALANTA.2013.12.054
Abstract: Ultrasonic energy is gaining momentum in Proteomics. It helps to shorten many proteomics workflows in an easy and efficient manner. Ultrasonic energy is nowadays used for protein extraction, solubilisation and cell disruption, to speed protein identification, protein quantification, peptide profiling, metal-protein complexes characterisation and imaging mass spectrometry. The present review gives a perspective of the latest achievements in ultrasonic-based s le treatment for proteomics as well as provides the basic concepts and the tools of the trade to efficiently implement this tool in proteomics labs.
Publisher: Wiley
Date: 18-04-2013
Abstract: In the present work, we report a novel on-target protein cleavage method. The method utilizes ultrasonic energy and allows up to 20 s les to be cleaved in 5 min for protein identification and one s le in 30 s for on-tissue digestion. The standard proteins were spotted on a conductive glass slide in a volume of 0.5 μL followed by 5 min of ultrasonication after trypsin addition. Controls (5 min, 37°C no ultrasonication) were also assayed. After trypsin addition, digestion of the tissues was enhanced by 30 s of ultrasonication. The s les were analyzed and compared to those obtained by using conventional 3 h heating proteolysis. The low s le volume needed for the digestion and reduction in s le-handling steps and time are the features that make this method appealing to the many laboratories working with high-throughput s le treatment.
Publisher: Wiley
Date: 06-01-2012
DOI: 10.1002/RCM.5325
Abstract: There is a need in imaging mass spectrometry to use the acquired isotope distribution to unequivocally determine the identity of a peptide ion. A way of achieving unambiguous differentiation of ions from protonated peptides from other [M + H](+) ions in a tissue would be via the direct on-tissue incorporation of (18)O into peptides. Tissues were first digested with trypsin for 3 h at 37 °C in a humidified chamber. For the (18)O-labelling of digested peptides 1 μL of H(2)(18)O/50 mM ammonium acetate (at pH 6.75) was added to the array of tryptic spots and incubated at room temperature for 20 min. α-Cyano-4-hydroxycinnamic acid was used as a matrix modifier. The mass spectral analysis of tissue sections was carried out using a matrix-assisted laser desorption/ionisation tandem time-of-flight (MALDI-TOF-TOF) instrument. On-tissue incorporation of (18)O into peptides cannot be carried out during the digestion step inside a humidified chamber. After tissue digestion for 3 h at 37 °C in an humidified chamber, (18)O labelling was carried out for 20 min at room temperature (no humidified chamber). No trypsin was needed to enhance the labelling. For first time the feasibility of (18)O-labelling of peptides in situ for tissues has been demonstrated. The method decouples protein digestion from peptide labelling and is performed in sequential steps. Furthermore, we observed that (18)O incorporation produces characteristic isotopic peptide distributions, thus making facile distinguishing peptides from other tissue molecular components that ionise in the MALDI ion source.
Location: Portugal
Location: Spain
Location: Portugal
No related grants have been discovered for Hugo M. Santos.