Forensic activation analysis

The use of activation analysis in criminal investigations (forensic activation analysis) is also well established. The basic idea here is to match the trace-element distributions found in bullets, paint, oil, and so on found at the scene of a crime with the trace-element distributions in objects found with criminal suspects. Such identification is rapid and nondestructive (allowing the actual evidence to be presented in court). Moreover, the probability of its correctness can be ascertained quantitatively. Other prominent examples of the use of forensic activation analysis involve confirmation of the notion that Napoleon was poisoned (by finding significant amounts of arsenic in hair from his head) and the finding that the activation analysis of the wipe samples taken from a suspect s hand can reveal not only if he or she has fired a gun recently but also the type of gun and ammunition used. 

M. E. Cowan, P. L. Purdon, C. M. Hoffman, R. Brunelle, S. R. Gerber, and M. Pro, Barium and Antimony Levels on Hands—Significance as Indicator of Gunfire Residue. Paper presented at the Second International Conference on Forensic Activation Analysis, Glasgow, 1972, Paper 21. 

Autoradiography, in Proceedings First Internat. Conf. on Forensic Activation Analysis, p. 119,... 

Thermal neutron activation analysis has been used for archeological samples, such as amber, coins, ceramics, and glass biological samples and forensic samples (see Forensic chemistry) as weU as human tissues, including bile, blood, bone, teeth, and urine laboratory animals geological samples, such as meteorites and ores and a variety of industrial products (166). 

In the modern forensic chemistry laboratory (Figure B) arsenic is detected by analysis of hair samples, where the element tends to concentrate in chronic arsenic poisoning. A single strand of hair is sufficient to establish the presence or absence of the element. The technique most commonly used is neutron activation analysis, described in Chapter 19. If the concentration found is greater than about 0.0003%, poisoning is indicated normal arsenic levels are much lower than this. 

Elemental Analysis, 2) Determination of Pellet Weight in Primers, 3) Determination of Gunpowder Residues in Forensic.Investigations, 4) Detection of Explosives in Buried Mines, 5) Detection of Hidden Explosives in Baggage, and 6) Explosives Safety in Neutron Activation Analysis... 

Study of chemical pathways in method development. Isotope dilution methods. Radioimmunoassay very important in biochemistry and medicine. Neutron activation analysis used for trace elements in geo-chemistry, semiconductor technology, pollution studies and forensic science. Relative precision of counting 1% if 104 counts are recorded. Assessment of pollution by radionuclides. 

Neutron activation analysis is an attractive method in many trace element problems, or where the total amount of sample is limited. Many geochemical studies of trace constituents and semi-conductor developments have used the technique, whilst in recent years pollution investigations have provided a new focus. In forensic science small flakes of paint, single hairs and a variety of other small samples have been analysed and identified by activation analysis. In recent years activation analysis has lost further ground to ICP-MS which provides more comprehensive information and is more readily operated. Sensitivity is also comparable in many cases. 

The coincidence technique has also been applied to the activation analysis of biological materials 79 82) and forensic materials 83>. 

Perkins, A. K., and R. E. Jervis Recent Forensic Applications of Instrumental Activation Analysis. The 1968 International Conference Modern Trends in Activation Analysis, Gaithersburg, Maryland, October 7—11, 1968, Paper 60. 

A wide array of laboratory techniques and instrumentation is used in forensic studies. This includes ultraviolet, infrared, and visible spectrophotometry neutron activation analysis gas chromatography and mass spectrophotometry high pressure liquid chromatography and atomic absorption spectrophotometry. The techniques and instrumentation chosen depend on the type of sample or substance to be examined. 

M. Jauhari, T. Sing, and S. M. Chatterji, Primer Residue Analysis of Ammunition of Indian Origin by Neutron Activation Analysis, Forensic Science International 19 (1982) 253. 

S. S. Krishnan, K. A. Gillespie, and E. J. Anderson, Rapid Detection of Firearm Discharge Residues by Atomic Absorption and Neutron Activation Analysis, Journal of Forensic Sciences 16 (1971) 144. 

Activation analysis has become, because of its extremely high sensitivity, an indispensable tool in a wide variety of fields ranging from science and engineering to industry, minerals exploration, " medicine, environmental monitoring, and forensic science. " The purpose of this chapter is not to present all the aspects, details, and applications of this field, but to discuss the major steps that comprise the method, the interpretation of the results, the errors and sensitivity of the method, and certain representative applications. The reader will find many more details and an extensive list of applications in the bibliography and the references given at the end of the chapter. 

Overall, activation analysis is a very powerful technique, as demonstrated by its wide use in so many different fields—i.e., chemistry, biology, medicine, forensic medicine, industry, archaeology, and environmental research. For details regarding these special applications, the reader is referred to Refs. 3-33 and to the bibliography of this chapter, in particular, to the books by Nargol-walla and Przybylowicz, and by Rakovic. 

Although capable of incredible sensitivity and selectivity, neutron activation analysis has never gained great popularity in forensic science. The major reason, of course, is that NAA i.s expensive and requires access to a nuclear reactor Today. NAA has been superseded in hair analysis by DNA fingerprinting. The amouni of DNA found at ihe rooi of one human hair is sufficient for DNA fingerprinting. Such techniques are much less expensive ai)d more readily available than neutron acm-ation analysis. 

Advantages Most forms of chemical analysis require vaporization, dissolution, or alteration of the analyzed sample in some way. Neutron activation analysis is a nondestructive process that can be used to study liquid, solid, or gaseous samples. Sensitive items, such as forensic evidence, meteorites, or artifacts, can be analyzed without harm. 

Dybezynski R, Boboli K. 1976. Forensic and environmental aspects of neutron activation analysis of single human hairs. Journal of Radioanalytical Chemistry 31 267-289. 

Loveridge and Smales (560) were the first to publish an extensive paper about the applications of activation analysis to biochemistry. Their report covered the period 1944-1957. Since then many other review articles have been written about its capabilities as a methodology to analyze for trace substances in problems from medicine, veterinary medicine, forensic medicine, dental science, pharmacology, botany and agriculture. More specifically, these articles can be categorized in the following manner ... 

In recent years life science researchers have become more earnest in their considerations that trace elements have important roles in physiology and pathology. So far, some of these experimenters have used activation analysis (1) to measure the elemental contents of biological tissues and fluids (2) to determine if a correlation exists between abnormal trace element concentration and certain types of diseases (3) as an investigational method for epidemiological functions (4) to measure metabolic functions (5) as a clinical and investigational method for toxicology (6) in total body in vivo studies (7) in in vivo studies with stable tracers and (8) in individual identifications for forensic requirements. 

The feasibility of using activation analysis to establish individuality characteristics resulted from studies made by Forshufvud, Smith and Wassen (280,281,876) and Smith (873) on the arsenic content of Napoleon I s hair and their interpretation of the arsenic content of the hair with respect to Napoleon s illness during 1816-1821. Since that time many other researchers have examined human hair, nails and other materials in order to assist in the identification of individuals in requirements of forensic science. Table V lists these investigators, the type of sample examined and the elements considered usable to determine individual characteristics. 

Tuckermann, Bate, and Leddicotte (947) have estimated the concen-tractions of Cu, Zn, Mn, As, Sb, and Fe in many different pharmaceutical preparations. Johansen, Lunde, and Steinnes (431) and Skinner, Lenfer, and Parkhurst (860) also carried out similar studies. Trace metal impurities in ascorbic acid (638) Br and 1 in sodium glutamate (169) selenium in nicotinic acid (677) trace metals in tartar emetic (10) and Mn and Zn in lactose (705,706) were determined by activation analysis. In other studies Bate and Pro (58) Leddicotte, Emery, and Bate (525) and Schlesinger et al. (820) found it feasible to characterize and identify the origin of drugs usually considered to be primarily of interest to forensic scientists. 

---