Search results for "010401 analytical chemistry"
showing 10 items of 1284 documents
Nitrogen and sulfur co-doped carbon nanodots toward bovine hemoglobin: A fluorescence quenching mechanism investigation
2018
A deep understanding of the molecular interactions of carbon nanodots with biomacromolecules is essential for wider applications of carbon nanodots both in vitro and in vivo. Herein, nitrogen and sulfur co-doped carbon dots (N,S-CDs) with a quantum yield of 16% were synthesized by a 1-step hydrothermal method. The N,S-CDs exhibited a good dispersion, with a graphite-like structure, along with the fluorescence lifetime of approximately 7.50 ns. Findings showed that the fluorescence of the N,S-CDs was effectively quenched by bovine hemoglobin as a result of the static fluorescence quenching. The mentioned quenching mechanism was investigated by the Stern-Volmer equation, temperature-dependent…
A multi-analytical non-invasive and micro-invasive approach to canvas oil paintings. General considerations from a specific case
2017
Abstract The investigation of artwork to understand story, state of conservation and to know about the composing materials is an issue that is getting growing attention in specialized literature. From a methodological point of view the scientific community is trying to reach a common proposal that could contribute to define a Standard Operating Procedure (SOP) for the application of portable non-invasive and microinvasive techniques for in-situ analyses. In this paper the oil painting on canvas “St. Girolamo nello studio” by Nicolo Buttafoco was investigated to known the materials and techniques used by the artist as well as to evaluate its preservation status. The survey has been conducted…
Compatibility of epirubicin-loaded DC bead™ with different non-ionic contrast media
2016
Purpose The aim of this study was to determine the compatibility of epirubicin-loaded DC bead™ with different non-ionic contrast media over a period of seven days when stored light protected under refrigerated conditions. Methods DC bead™ (2 ml) (Biocompatibles UK Ltd) of the bead size 70–150 µm ( = DC bead M1) or bead size 100–300 µm were loaded with 75 mg epirubicin powder formulation (Farmorubicin® dissolved in 3 ml water for injection to a concentration of 25 mg/ml) or 76 mg epirubicin injection solution (Epimedac® 2 mg/ml) within 2 h or 6 h, respectively. After removal of the excess solution, the epirubicin-loaded beads were mixed in polypropylene syringes with an equal volume (∼1.5 ml…
Footprint of carbonyl compounds in hand scent by in-tube solid-phase microextraction coupled to nano-liquid chromatography/diode array detection
2019
Abstract In the present work, the footprint of carbonyl compounds in hand scent was achieved by a miniaturized method consisting of sampling with cotton gauze, extraction and derivatization using 2,4-dinitrophenylhydrazine (DNPH) and preconcentration, separation and detection by in-tube solid-phase microextraction (IT-SPME) coupled to nano-liquid chromatography/Uv–vis diode array detection. The coupling IT-SPME-nanoLC-DAD was solved by using a two-valve system: the first valve for loading the sample and the second one to perform IT-SPME. To this aim, a nanoparticle-based capillary column was employed. Firstly, the transfer time from the load loop to the NP-based capillary column in the IT-S…
Development of a sequential data correction method for isotope ratio analysis by resonance ionization mass spectrometry
2015
A sequential data correction method using several experimental parameters of pulsed resonance ionization mass spectrometry was developed to reduce mass discrimination effects for isotope ratio analysis as well as fluctuations in the ion count rate. This correction method was applied to isotope ratio determination of stable titanium isotopes using a two-step, single color ionization scheme. A significant improvement of the precision of the measured isotopic ratio of stable titanium isotopes was demonstrated after correction with a parameter set consisting of laser power, atmospheric pressure, and laser frequency.
Status of the project TRAPSENSOR: Performance of the laser-desorption ion source
2013
Abstract Penning traps provide mass measurements on atomic nuclei with the highest accuracy and sensitivity. Depending on the experiment and on the physics goal, a relative mass uncertainty varying from 10 −7 to below 10 −11 is required. Regarding sensitivity, the use of only one ion for the measurement is crucial, either to perform mass measurements on superheavy elements (SHE), or to reach δ m / m ≈ 10 - 11 in order to contribute to the direct determination of the mass of the electron-antineutrino with accurate mass measurements on specific nuclei. This has motivated the development of a new technique called Quantum Sensor based on a laser-cooled ion stored in a Penning trap, to perform m…
A new beamline for energy-dispersive high-resolution PIXE analysis using polycapillary optics
2019
Abstract A new beamline for high energy resolution PIXE measurements is presented. This new setup includes options for both in-air and vacuum measurements. For the high energy resolution transition-edge sensor array, a polycapillary lens is used for detecting low-energy X-rays down to 0.5 keV and to increase the effective solid angle. X-ray transmission of the polycapillary lens was characterized using two calibration standards. The gain obtained by adding a polycapillary lens was 1.6–2.3 at energies between 2.1 keV and 4.5 keV. From 1.04 to 1.74 keV the gain is increased to 2.1–3.0, and at energies 4.9–8.0 keV the gain is between 1.6 and 0.65. The measured gain agreed well with theoretical…
Multi-technique characterization of gold electroplating on silver substrates for cultural heritage applications
2017
Proceedings of the 12th European Conference on Accelerators in Applied Research and Technology (ECAART12).-- et al.
Recent developments in Penning-trap mass spectrometry
2016
Abstract Penning-trap mass spectrometry provides atomic masses with the highest precision. At accelerator-based on-line facilities it is applied to investigate exotic radionuclides in the context of tests of fundamental symmetries, nuclear structure studies, and nuclear astrophysics research. Recent progress in slowing down radioactive ion-beams in buffer-gas cells in combination with advanced ion-manipulation techniques has paved the way to reach nuclides ever-more far from stability. In this endeavor many efforts are underway to increase the sensitivity, the efficiency, and the precision of Penning-trap mass spectrometry. In this article some recent experimental developments are addressed…
Study of radial motion phase advance during motion excitations in a Penning trap and accuracy of JYFLTRAP mass spectrometer
2021
Phase-imaging ion-cyclotron-resonance technique has been implemented at the Penning-trap mass spectrometer JYFLTRAP and is routinely employed for mass measurements of stable and short-lived nuclides produced at IGISOL facility. Systematic uncertainties that impose limitations on the accuracy of measurements are discussed. It was found out that the phase evolution of the radial motion of ions in a Penning trap during the application of radio-frequency fields leads to a systematic cyclotron frequency shift when more than one ion species is present in the trap during the cyclotron frequency measurement. An analytic expression was derived to correctly account for the shift. Cross-reference mass…