Advancements in multi-gas sensing
Suggested reading before the seminar: http://pubs.acs.org.ezproxy.uky.edu/doi/full/10.1021/ac404162w
Single Particle Inductively Coupled Plasma Mass Spectrometry (sp-ICPMS) for Nanoanalysis
Abstract:
Nanomaterials have become one of the most thriving areas for research and development in the academia and industry, proven by the exponential rise of number of research articles published over the last decades. It’s been used in a wide array of fields such as energy, environment, automobile, medicine, personal care, etc., owing to its special physico-chemical properties due to small size. But the increase of applications of nanomaterials also gave rise to a new health and environmental hazard, which is nanotoxicity. Nanomaterials have been linked to the generation of reactive oxygen species (ROS) in plants, which is responsible for the damage of cell membrane, disruption of ATP production and DNA replication. It’s been also linked to the lung inflammation in rats. Given the scenario, the demand for new instrumental methods for the identification and quantification of nanomaterials in air, water, soil, and biological matrices is in rise.
Single Particle Inductively Coupled Plasma Mass Spectrometry (sp-ICPMS) has become a promising tool for the identification and quantification of nanomaterials in practically all types of sample matrixes. It removes the lack of chemical selectivity of other competitive methods such as transmission electron microscopy (TEM), Dynamic light scattering (DLS) and inability to analyze samples in environmental and biologically relevant conditions. Despite being able to analyze nanoparticles in a one-by-one (single particle) manner, it suffers from some key limitations such as large ample consumption, low transport efficiency (9-10%), particles embedded in slid matrices, etc. Substrate assisted laser desorption (SALD) has been used with sp-ICPMS as sample introduction method instead of nebulizer to overcome these limitations. A frequency-quintupled Nd:YAG laser (213 nm) was used for laser ablation. Conditions such as laser fluence, laser beam scan rate and carrier gas flow rate were optimized using commercially available gold nanoparticles (AuNPs) of 56 nm and 86 nm. A transport efficiency of 61% was achieved for 56 nm AuNPs. The results were compared with the established method nebulizer sp-ICPMS. Use of SALD sp-ICPMS has enabled to reduce sample consumption, increase transport efficiency and better sensitivity.
References:
1. Benesova et al. Anal. Chem. 2016, 88, 2576
2. Pace et al. Anal. Chem.2011, 83, 9361
3. Malysheva et al. on. Envir Sci. Technol.2016, 50, 12455
4. Gunsolus, I. L.; Hynes, C. L. Anal. Chem. 2016, 88, 451
5. Peters et al. J. Anal. At. Spectrom. 2015, 30, 1274
Suggested reading before the seminar: http://pubs.acs.org.ezproxy.uky.edu/doi/abs/10.1021/acs.analchem.5b02421
Compositional Analysis of Aerosols Using Calibration-Free Laser-Induced Breakdown Spectroscopy
Andrew Bradley1
1Dept. of Chemistry, University of Kentucky
Due to the difficulty of analyzing the composition of aerosols, calibration-free laser induced was proposed. An Nd-YAG laser was used for the optical breakdown. The beam was focused on a flux of helium charged with alumina ions. Laser and plasma radiation was separated via a dichroic mirror. The optical fiber was coupled to an echelle spectrophotometer. A charge-coupled device matrix detector was used for photon detection. All spectral data were analyzed on the base of a partial local thermodynamic equilibrium; therefore, Boltzmann equilibrium distributions were assumed for the vapor atoms except for the helium atoms and ions. The results concluded that calibration-free LIBS is capable of performing compositional analyses of aerosols in a helium flux with a 10% accuracy. However, accurate composition measurements were only seen for delays between the laser pulse and the detector gate ≤ 1 μs. This is due to the electron density has to be large enough to allow collisional equilibrium for the aerosol species.
Suggested reading before the seminar: http://pubs.acs.org.ezproxy.uky.edu/doi/full/10.1021/acs.analchem.6b00329
Molecularly Imprinted Polymer-Based Plasmonic Immunosandwich Assay for Fast and Ultrasensitive Determination of Trace Glycoproteins in Complex Samples.
Suggested reading before the seminar: http://pubs.acs.org.ezproxy.uky.edu/doi/full/10.1021/acs.analchem.6b03597
Data Streaming for Metabolomics.
Suggested reading before the seminar: http://dx.doi.org/10.1021/acs.analchem.6b03890
Gender Determination by Raman Spectroscopy of a bloodstain.
Suggested reading before the seminar: http://pubs.acs.org.ezproxy.uky.edu/doi/full/10.1021/acs.analchem.6b02986
Discussion about seminars and scheduling talks
