This book represents a collection of papers presented at the 4th International Symposium on Analysis and Detection of Explosives held at the Mitzpeh Rachel Kibbutz Guesthouse in Jerusalem, September 7 to 10, 1992. The Symposium was attended by 150 participants from 20 countries and 50 lectures were given including 4 invited keynote lectures. The purpose of the Symposium, as the previous Symposia, was to present and to discuss new approaches, new applications, new methods and techniques in analysis and detection of explosives. The Symposium was, according to the feedback received from many participants, very successful and met the anticipated expectations. New collaborative initiatives between various laboratories from different countries were formed, which is a necessity in our common goals of law enforcement, aviation security and environmental quality, issues which are closely related to the analysis of explosives. I would like to extend my thanks to the Weizmann Institute of Science and the Israel National Police for sponsoring the Symposium, to the contributing Institutions and Agencies for making this Symposium financially possible, and to the members of the International Committee for helpful advice. I am most thankful to my colleagues from the Organizing Committee, especially Dr. Joseph Almog and Dr. Shmuel Zitrin from the Israel National Police, for helping in the organization of this Symposium.

This book examines both the potential application of electronic nose technology, and the current state of development of chemical sensors for the detection of vapours from explosives, such as those used in landmines. The two fields have developed, somewhat in parallel, over the past decade and so one of the purposes of this workshop, on which the book is based, was to bring together scientists from the two fields in order to challenge the two communities and, mutually, stimulate both fields.

It begins with a review of the basic principles of an electronic nose and explores possible ways in which the detection limit of conventional electronic nose technology can be reduced to the level required for the trace levels observed for many explosive materials. Next are reviews of the use of several different types of solid-state chemical sensors: polymer-based sensors, i.e. chemiluminescent, fluorescent and optical, to detect explosive materials; metal oxide semiconducting resistive sensors; and then electrochemical sensors. Next, different pattern recognition techniques are presented to enhance the performance of chemical sensors. Then biological systems are considered as a possible blue-print for chemical sensing. The biology can be employed either to understand the way insects locate odorant sources, or to understand the signal processing neural pathways. Next is a discussion of some of the new types of electronic noses; namely, a fast GC column with a SAW detector and a micromechanical sensor. Finally, the important issues of sampling technologies and the design of the microfluidic systems are considered. In particular, the use of pre-concentrators and solid phase micro extractors to boost the vapour concentration before it is introduced to the chemical sensor or electronic nose.

One of the surprising things about the natural world is that animals are dying around us all the time and yet we rarely see any evidence of it. This is a testimony to the efficiency of the large variety of organisms which decompose animal corpses. Whilst bacteria and fungi are the main groups involved in decomposition processes, the larger insects additionally provide an important physical disruption of body tissues, which aids the penetration of micro organisms and speeds the collapse of the body structure. A human corpse is treated no differently and the same groups of organisms are involved. From a forensic science viewpoint the universality of the decay process provides two major advantages. Information based on the decomposition of animals is of considerable value when considering human cases and the successional pattern of decay is broadly equivalent wherever the process is being studied. Historically, the usefulness of insects in solving crime can be traced back in the literature to the 13th century. McKnight 1, 2] translated a Chinese text of this period which contains an account of how a law officer dealt with a case of murder in the rice fields. Death had been caused by a sickle and the official ordered all the field workers to line up and lay their sickles on the ground in front of them. Flies began to be attracted to one of the sickles whereupon its owner confessed to the crime."

This book represents a collection of papers presented at the 4th International Symposium on Analysis and Detection of Explosives held at the Mitzpeh Rachel Kibbutz Guesthouse in Jerusalem, September 7 to 10, 1992. The Symposium was attended by 150 participants from 20 countries and 50 lectures were given including 4 invited keynote lectures. The purpose of the Symposium, as the previous Symposia, was to present and to discuss new approaches, new applications, new methods and techniques in analysis and detection of explosives. The Symposium was, according to the feedback received from many participants, very successful and met the anticipated expectations. New collaborative initiatives between various laboratories from different countries were formed, which is a necessity in our common goals of law enforcement, aviation security and environmental quality, issues which are closely related to the analysis of explosives. I would like to extend my thanks to the Weizmann Institute of Science and the Israel National Police for sponsoring the Symposium, to the contributing Institutions and Agencies for making this Symposium financially possible, and to the members of the International Committee for helpful advice. I am most thankful to my colleagues from the Organizing Committee, especially Dr. Joseph Almog and Dr. Shmuel Zitrin from the Israel National Police, for helping in the organization of this Symposium.

This book examines both the potential application of electronic nose technology, and the current state of development of chemical sensors for the detection of vapours from explosives, such as those used in landmines. The two fields have developed, somewhat in parallel, over the past decade and so one of the purposes of this workshop, on which the book is based, was to bring together scientists from the two fields in order to challenge the two communities and, mutually, stimulate both fields.

It begins with a review of the basic principles of an electronic nose and explores possible ways in which the detection limit of conventional electronic nose technology can be reduced to the level required for the trace levels observed for many explosive materials. Next are reviews of the use of several different types of solid-state chemical sensors: polymer-based sensors, i.e. chemiluminescent, fluorescent and optical, to detect explosive materials; metal oxide semiconducting resistive sensors; and then electrochemical sensors. Next, different pattern recognition techniques are presented to enhance the performance of chemical sensors. Then biological systems are considered as a possible blue-print for chemical sensing. The biology can be employed either to understand the way insects locate odorant sources, or to understand the signal processing neural pathways. Next is a discussion of some of the new types of electronic noses; namely, a fast GC column with a SAW detector and a micromechanical sensor. Finally, the important issues of sampling technologies and the design of the microfluidic systems are considered. In particular, the use of pre-concentrators and solid phase micro extractors to boost the vapour concentration before it is introduced to the chemical sensor or electronic nose.

The mass spectrometer is now an integral part of every forensic laboratory. This methodology results in lower detection limits, more reliable identification, and greater analytical accuracy. Completely revised and updated, and exploring the latest developments in the field, Advances in Forensic Applications of Mass Spectrometry provides a comprehensive reference guide to forensic applications using modern mass spectrometry techniques. The text features methods developed from advanced instrumentation, drug detection and toxicological analysis, methodology of applications of stable isotope ratios, and procedures for analysis of explosives in post-blast residues.

Forensic Applications of Mass Spectrometry combines the most current developments in applications of mass spectrometry techniques to forensic analyses. The techniques discussed include:
o capillary-GC/MS
o thermospray-LC/MS
o tandem mass spectrometry (MS/MS)
o pyrolysis-GC/MS
o isotope ratio mass spectrometry
The applications include:
o analysis of body fluids and hair for drugs of abuse
o drug testing in sports
o analysis of accelerants in fire debris
o detection of hidden explosives in luggage and mail
o identification of explosives in post-explosion debris
o examination of evidential materials (paints, fibers, synthetic polymers)
o authentication of regulated products (flavoring substances, fruit juices)
o protection of industrial products by isotopic signature

The detection of hidden explosives has become an issue of utmost importance in recent years. While terrorism is not new to the international community, recent terrorist attacks have raised the issue of detection of explosives and have generated a great demand for rapid, sensitive and reliable methods for detecting hidden explosives. Counterterrorist Detection Techniques of Explosives covers recent advances in this area of research including vapor and trace detection techniques (chemiluminescence, mass spectrometry, ion mobility spectrometry, electrochemical methods and micromechanical sensors, such as microcantilevers) and bulk detection techniques (neutron techniques, nuclear quadrupole resonance, x-ray diffraction imaging, millimeter-wave imaging, terahertz imaging and laser techniques). This book will be of interest to any scientists involved in the design and application of security screening technologies including new sensors and detecting devices which will prevent the smuggling of bombs and explosives.
* Covers latest advances in vapor and trace detection techniques and bulk detection techniques
* Reviews both current techniques and those in advanced stages of development
* Techniques that are described in detail, including its principles of operation, as well as its applications in the detection of explosives