UNIVERSITY OF PUERTO RICO
MAYAGUEZ CAMPUS CHEMISTRY DEPARTMENT
Departmental Seminar
By
Annette M. Colón-Mercado, M.S.
Doctoral Candidate
Friday April 21st
10:30 am
Haga clic aquí para unirse a la reunión
ID de la reunión: 225 019 902 984
Código de acceso: 2wtcVi
Trace detection of C-4 on aluminum using Mid-Infrared Reflection-Absorption Quantum Cascade Laser Spectroscopy
Abstract
A comparison between a LaserScan quantum cascade laser system coupled to grazing angle probe (QCL-GAP) optical mount and a Mini-QCL operating at the grazing angle of incidence (Mini-QCL-GA) for the detection of the high explosive (HE) formulation C-4 is reported. The optical arrangement in both systems enables Reflection-Absorption Infrared Spectroscopy (RAIRS), considered the most sensitive infrared spectroscopy (IRS) technique. The difference in detection is mainly due to the doubled pass effect in the QCL-GAP vs. the single pass in the Mini-QCL-GA. C-4 samples deposited on aluminum (Al) substrates using inkjet printers were used as standards and samples. Multivariate Analysis (MVA) routines were used to detect and classify the explosive formulation traces, allowing to obtain precise results. Partial least squares (PLS) regression models using several preprocessing steps assisted in the samples’ quantitative analysis.
AND
Detection of micro and nano crystals of RDX and PETN spatially separated using 2,4-DNT metastable phase
PI/Ad Honorem Committee Member: Leonardo Pacheco Londoño, Ph.D.
Abstract
Micro and sub-micro particles high energetic material (HEM: RDX and PETN) were deposited on different surfaces using a solution of HEM in 2,4 DNT (DNT) metastable phase. The metastable phase exists in the form of microdroplets on the different surfaces for TNT and DNT when a solution of the HEM is deposited on a surface. The solvent evaporates leaving spatially separated microdroplets. Changes in pressure evaporated the DNT and as a result micro and nanocrystals were obtained in the place of the droplets. Characterization of the HEM microcrystals was evaluated using FT-IR to confirm the vibrational signatures. Morphological studies were performed to understand the particle size and ratio of the crystals.