Whether or not the substrate under the residue contributes to the emission, the amount of material is a limitation in the micro-analysis of explosive residues. However, the amount of residue is often in the order of a few nanograms and is often removed after the first laser shot, making subsequent analysis of the residues difficult or impossible. As compared to the analysis of trace components, the analysis of a residue should be relatively simple because the specimen is in the form of a separate phase from the object on which it is deposited. Plasma imaging demonstrates that the species distribution along the plume changes with beam focal conditions, which is exploited here to further increase the selectivity of the approach.Įspecially challenging is the detection of explosives when analyzed as residues. The results demonstrate that selective sampling is successfully achieved in all cases when the plasma formation threshold of the residues and the object is substantially different. 2-Mononitrotoluene (MNT), 2,6- dinitrotoluene (DNT), and 2,4,6-trinitrotoluene (TNT) are used as model residues, whereas nylon and Teflon are used as illustrative surfaces of daily life objects. Since ablation and subsequent plasma formation are sensitive to the beam focal conditions and the pulse energy deposited on the surface, the choice of an appropriate set of experimental conditions increases the surface sensitivity of the analysis and hence a selective inspection of the residue in the absence of spectral contribution from the organic support analyzed. Under these circumstances LIBS suffers from the limitations imposed by the limited spectroscopic information available for the analysis. Organic explosives are difficult to analyze when present as residues on organic materials. All subjects Allied Health Cardiology & Cardiovascular Medicine Dentistry Emergency Medicine & Critical Care Endocrinology & Metabolism Environmental Science General Medicine Geriatrics Infectious Diseases Medico-legal Neurology Nursing Nutrition Obstetrics & Gynecology Oncology Orthopaedics & Sports Medicine Otolaryngology Palliative Medicine & Chronic Care Pediatrics Pharmacology & Toxicology Psychiatry & Psychology Public Health Pulmonary & Respiratory Medicine Radiology Research Methods & Evaluation Rheumatology Surgery Tropical Medicine Veterinary Medicine Cell Biology Clinical Biochemistry Environmental Science Life Sciences Neuroscience Pharmacology & Toxicology Biomedical Engineering Engineering & Computing Environmental Engineering Materials Science Anthropology & Archaeology Communication & Media Studies Criminology & Criminal Justice Cultural Studies Economics & Development Education Environmental Studies Ethnic Studies Family Studies Gender Studies Geography Gerontology & Aging Group Studies History Information Science Interpersonal Violence Language & Linguistics Law Management & Organization Studies Marketing & Hospitality Music Peace Studies & Conflict Resolution Philosophy Politics & International Relations Psychoanalysis Psychology & Counseling Public Administration Regional Studies Religion Research Methods & Evaluation Science & Society Studies Social Work & Social Policy Sociology Special Education Urban Studies & Planning BROWSE JOURNALSĪ method for selective sampling and analysis of explosive residues on solid surfaces based on laser-induced breakdown spectroscopy (LIBS) is presented.
0 Comments
Leave a Reply. |