Volatile Biomarkers

Non-Invasive Diagnosis in Physiology and Medicine

Cristina Davis, Jonathan Beauchamp, Anton Amann, David Smith

• Publisher: Elsevier
• Year: 2013
• eBook ISBN: 9780444626202
• Topic: Physical Sciences
• Subtopic: Analytic Chemistry

Volatile organic compounds (VOCs) in exhaled breath, sweat or urine carry much information on the state of human health. The role of VOCs in clinical diagnosis and therapeutic monitoring is expected to become increasingly significant due to recent advances in the field. Volatile Biomarkers: Non-Invasive Diagnosis in Physiology and Medicine includes the latest discoveries and applications for VOCs from the world's foremost scientists and clinicians working in this emerging analytic area. - Appeals to a multidisciplinary audience, including scientists, researchers, and clinicians with an interest in breath analysis - Features the latest scientific research and technical breakthroughs in the diagnostic and therapeutic aspects of volatile organic compounds - Includes case presentations documenting applications in multiple areas of human health and safety

PART I Urban Search and Rescue Operations

Chapter 24 Potential Applications of Volatile Organic Compounds in Safety and Security

Chapter 24

Potential Applications of Volatile Organic Compounds in Safety and Security

Agapios Agapiou^*, Pawel Mochalski^{†, ‡}, Alex Schmid^† and Anton Amann^†, ^*National Technical University of Athens (NTUA), School of Chemical Engineering, Sector I, 9 Iroon Polytechniou Street, 15773 Athens, Greece, ^†Breath Research Institute, Austrian Academy of Sciences, Rathausplatz 4, 6850 Dornbirn; Univ.-Clinic for Anesthesia, Innsbruck Medical University, Anichstr, 35, 6020 Innsbruck, Austria, ^‡Institute of Nuclear Physics PAN, Radzikowskiego 152, 31342 Kraków, Poland.

Acknowledgement

The research leading to these results has received funding from the European Community’s Seventh Framework Program (FP7/2007-13) under grant agreement No. 217967 (“SGL for USaR” project, Second Generation Locator for Urban Search and Rescue Operations, www.sgl-eu.org). We appreciate funding from the Austrian Federal Ministry for Transport, Innovation and Technology (BMVIT/BMWA, project 836308, KIRAS). We greatly appreciate the generous support of the government of Vorarlberg and its governor Landeshauptmann Dr. Herbert Sausgruber.

24.1 Introduction

The occurrences of natural and man-made disasters are increasing worldwide. In the past decade, earthquakes have accounted for nearly 60% of all disaster-related mortalities, causing more than 780,000 deaths and directly affecting another 2 billion people.¹ In view of global urbanization and large urban center vulnerability, and bearing in mind that some of the most populous cities in the world (e.g. Tokyo, Mexico City, New York, Mumbai, Delhi, Jakarta, Shanghai, Calcutta, Los Angeles) are located in seismic zones, the probability of a near-future mega earthquake event is expected to increase.^2,3

The survival rate of entrapped victims diminishes dramatically over time; therefore, there is a need for immediate and acute response in the disaster zone. The death toll from the last devastating earthquakes in Japan (2011), China and Haiti (2010), Indonesia and Italy (2009), reinforced the need for new, innovative technical solutions for enhancing the capabilities and intervention of urban search and rescue (USaR) teams. Until now, various instruments like geophones, telescopic or infra-red (IR) cameras, and sonars have been deployed to support the work of USaR teams. Nevertheless, the position of canines in USaR operations remains invincible and is considered as the “gold standard.”⁴ Search dogs exhibit excellent scenting skills and are able to search relatively large areas in a short period of time. However, they can easily get stressed, their working time is relatively short (30 min, with a subsequent break for 2 h) and their training is time-consuming and expensive.⁵ These limitations have generated demands for new technical search tools, which could complement, or even replace their work.

In this context, knowledge of the human scent profile and its characteristics in the disaster environment is of particular importance. Volatile species that form the human scent are released from different biological fluids (urine, blood, sweat) and tissues (skin, lungs, bowels). Their emissions depend on the conditions in the entrapment scene (confined space volume, type of collapse, temperature, humidity), the duration of entrapment, and the medical status of entrapped victims. In the entrapment environment, scent constituents are spread by air currents throughout the ruins, interact with the debris materials (brick, concrete, glass, wood, steel, etc.), and mix with environmental contaminants. Consequently, the concentration of the airborne human scent markers is low, making its detection and identification a really challenging task.

24.2 Chemical analysis of breath

Human breath contains numerous volatile organic compounds (VOCs) having great potential for medical, toxicological, and forensic applications. This is due to the fact that breath VOCs correlate quite well with numerous diseases, metabolic disorders, or exposure to frequently toxic environmental contaminants. Recent advances in analytical technologies resulted in novel, sensitive, and portable instruments (e.g. Ion Mobility Spectrometry, IMS⁶) allowing the on-site determination of VOCs. As a result, new challenging and exciting applications are arising in safety (exposure) and security (natural or man-made disasters) areas. Nevertheless, criteria for using breath analysis in these crucial applications need to be defined along with standardization procedures. Additionally, high throughput and sensitivity methods have to be developed.

Currently, the main applications of breath analysis in safety and security areas can be listed as follows:

• Detection of human presence.

• Identification of interactions of humans with materials and the environment leading to:

– Illegal acts.

– Contamination.

– Exposure to toxics.

– Criminal actions.

– Law enforcement applications.

Human expired air consists of nitrogen, oxygen, carbon dioxide, water vapor, and numerous VOCs.^7–9 Although VOCs are a tiny percentage of the expired air, they can provide important medical information. VOCs in expired air are generally divided into endogenous (those that are produced in the body from metabolic processes; products of metabolism) and exogenous substances (originating outside the body). Expired air analysis is currently a field that has been widely applied in medical diagnostics, search, and rescue operations and for monitoring human exposure to specific environments. For instance, breath analysis has been applied by numerous research groups to the diagnosis of cancer by correlating the VOCs with the associated metabolic pathways leading to cancer.^8,10–14

Chemical analysis of expired air can, in principle, provide information on human exposure to chemical, biological, and radiological agents.^15–17 Such information can be useful for identifying a person’s route (sites visited) and occupation (even an illegal one), especially when unusual chemicals are present in the visited or work places (e.g. illegal drug labs, explosives). Chemical analysis of breath also has potential biometric applications. This application of expired air analysis results from the fact that vapors of chemical agents, solvents, and explosives can be inhaled by humans, distributed in human tissues, and finally detected in expired air. Furthermore, strong and fast metabolic disorders resulting from biological infection and radiological exposure produce increased quantities of certain endogenous compounds, which can be directly determined from the chemical components of the expired air.

24.3 Analytical instrumentation; field technology

Until recently, the chemical analysis of breath was scientifically and technically difficult. Among the scientific problems frequently encountered were: the lack of standardization in breath sampling, difficulties in establishing reference groups, variability in the composition of expired air during day time, risk of contamination of the sample during measurements, ultra low concentrations of analytes of interest (from low ppm to low ppt), the necessity of pre-concentration, difficulties in differentiating endogenous from exogenous VOCs, difficulties in discriminating expired air components from high backgrounds, and the long time often required for analysis.

On the other hand, breath tests are non-invasive: breath can be sampled as often as it is desirable, even in real time, or during sleep,^18,19 exercise (e.g. during pedaling an ergometer^20–26), during almost any human activity, providing unique benefits compared to conventional urine and blood sampling and testing. Note, also, the ability of sampling from handicapped people, small children, old people, critically ill patients in intensive care,^27,28 and even in the perioperative setting.²⁹

Scientific and technical advances over the last 10 years have established breath testing as a very promising technique with several applications and potential for clinical applications.^30,31 Currently, several analytical techniques offer portable, selective, and very sensitive instruments ready to be used during field applications. These techniques embrace Ion Mobility Spectrometry (IMS), potentially coupled to a multicapillary column (MCC-IMS),^32–34 chemical sensors or e-nose.^35,36 In addition, various immobile or bench top, however very sensitive techniques, such as gas chromatography with mass spectrom...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of Contributors
• Foreword
• PART A Interpretation of Breath Analysis Data
• PART B Real-Time Analysis of Exhaled Breath
• PART C Physiological and Clinical Studies
• PART D Nitric Oxide, NO, and Carbon Monoxide, CO
• PART E Clinical Breath Tests
• PART F Development and Use of Sensors
• PART G Exhaled Breath Condensate (EBC) and Particulates
• PART H Volatiles of Microbial Origin: Urine, Stool and in vitro Cultures
• PART I Urban Search and Rescue Operations
• Index