I’
Geoffrey Davies Institute for Chemical Analysis, Applications and Forensic Science Northeastern University Boston. MA 021 15
Criminalistics, which is part of the wider field of forensic science, is concerned with the collection, laboratory evaluation, and interpretation of physical evidence arising from a crime or a suspicious incident (e.g., an unexplained death) ( I ) . A great variety of evidence material is submitted to the crime laboratory for evaluation as part of the investigative and judicial processes. The current heavy workloads of crime laboratory personnel are largely the result of two factors: The rapidly increasing crime rate The greater emphasis which is being placed on physical evidence in the courts as a result, in part, of the report from the President’s Commission on Crime in 1967 ( 2 ) . The greater utilization of physical evidence in the investigative and judicial processes has created career opportunities for chemistry graduates, as well as providing challenges for educators and researchers in contributing to the overall effectiveness of criminalistics laboratory operations. Previous articles (3-6) have focused on the function, status, and needs of the criminalistics profession. A symposium, “Educational and Scientific Progress in Forensic Science,” which was cosponsored by the Analytical and Chemical Education Divisions of the ACS and the American Academy of Forensic Sciences a t the recent ACS National Meeting in Atlantic City, 318A
provided a useful forum for the discussion of current educational and scientific progress in criminalistics. This article will summarize the topics presented a t the symposium. Before delving into this, however, it will be useful to review the criminalistics operation so that the later discussion can be put into perspective.
Nature of Criminalistic Investigations As noted above, criminalistic investigations are essentially a service function of the investigative and judicial systems. Although the detailed chain of events which leads to court testimony by an expert witness depends to some extent on the type and circumstances of a particular crime, the criminalistic investigative process can be broadly broken down into four phases: Collection of evidence Laboratory measurements Interpretation of results Court testimony. The actual caseload often places heavy demands on the facilities and manpower of the criminalistics laboratory. Also of importance is the legal requirement that the integrity of each item of evidence be preserved throughout a particular case. This requirement calls for an efficient criminalistics operation a t the local level (7).
ANALYTICAL CHEMISTRY, VOL. 47, NO. 3, MARCH 1975
Collection of Evidence The manner in which the crime scene is searched and evidence is selected and preserved is crucial to the criminalistics operation (7). The person collecting the materials must not only attempt to reconstruct the crime but must also appreciate the potential value of each type of evidence in the investigation. Since the laboratory criminalist is in the best position to seek and select the evidence which is most likely to be amenable to useful laboratory measurement and interpretation, it can realistically be argued that a laboratory criminalist should supervise the search and collection phase. However, the existing heavy caseloads in most American laboratories preclude the direct involvement of criminalists in the collection phase; even in the most advanced judicial systems (5, 7 , 8 ) ,direct involvement is almost entirely restricted to major crimes (e.g., bombings, homicide, suicide, and hitand-run incidents). This calls for a substantial training program for policemen, firemen, and evidence technicians, emphasizing the importance of proper evidence collection. A number of criminalists are actively involved in such educational efforts, which serve to increase the effectiveness of the overall criminalistic operation. Laboratory Measurements Among the types of evidence sub-
EDUCATIONAL AND SCIENTIFIC
! 1
mitted to the laboratory are solid materials (glass, fibers, soils, paint chips, charred wood, discharged bullets), biological samples (whole blood, blood and seminal stains), samples obtained from suspects (personal property, hand swabs, blood and urine samples), and impressions obtained from the crime scene (footprints, toolmarks, fingerprints). In many cases, the laboratory seeks evidence which will prove the truth or otherwise of the victim’s, suspect’s, or eyewitness’ statements. The choice of an analytical procedure for the detailed examination of a particular item of evidence depends on many factors, including likely identifying characteristics and the nature of the crime. The crime laboratory must have the facilities and expertise to apply a wide range of analytical procedures to the spectrum of evidence material. In addition, the criminalistic team must often be selective in its choice of evidence for evaluation, especially when items have been indiscriminately collected and the laboratory caseload is large. The majority of analyses carried out in the criminalistics laboratory are comparative, in that they are aimed a t establishing that two pieces of material have a common origin. Even today, the simple, compound or comparison microscope is the most widely used instrument. An increasing number of examinations now involve the identification and quantitative determination of particular elements, compounds, or characteristics under difficult analytical circumstances. A particularly good example is the absolute determination of the levels of Sb and Ba in a hand swab obtained for analysis of gunshot residue by neutron activation (9) or flameless atomic absorption spectrosCOPY (IO).
In general, analytical measurements must be objective, inexpensive, rapid, and reproducible to be compatible with time and manpower constraints. The aim of current research is to improve the capabilities of established laboratory techniques and to encourage the use of newer methodology (scanning electron microscopy, highspeed liquid chromatography, and electroanalysis) in the evaluation of a wide range of physical evidence materials. Interpretation of Results
The goal of laboratory measurements is to determine the nature and origin of a particular item of evidence: the basis for interpretation depends on the evidence class and the procedure used for identification. A few examples will serve to illustrate the different kinds of information which are necessary to draw conclusions for commonly occurring types of physical evidence. The comparison microscope is used in many laboratories to visually compare the rifling and firing pin impressions on a bullet recovered from a crime scene with those of a test bullet fired from a suspect weapon. If a weapon has not been recovered, the bullet may be compared with items in a reference collection so that the type of weapon, and possibly its owner, can be established. However, recovered bullets are often badly deformed, making identification difficult and sometimes impossible. Similarly, ink identification by thin-layer chromatography ( 1I ) is based on a comparison of the sample chromatogram with those of a reference collection of inks: this data base allows the establishment of criminal forgery and the backdating of questioned documents.
Report
The genetic typing of bloodstains (12) is based on the different electrophoretic properties of known protein phenotypes. Here, the availability of a number of genetically independent “markers” allows interpretation through the consideration of population distribution data ( 5 ) .The establishment of a significantly high level of a particular drug or toxin in a sample is also based on a comparison with statistical data, obtained from general population studies ( 4 ) . There are two important boundary conditions in crime laboratory evaluations: There are often time and other constraints on the number of different measurements that can be made on a given item of evidence. The criminalist must be familiar with the most distinctive identifying features and must understand the basis of comparison of his measurements with test or reference data. Since the conclusions are essentially a determination of the probability of criminal involvement, they are useless in the absence of clearly defined and distinguishable standards, either from test samples, reference collections, or statistical background data. Court Testimony
It takes several years of criminalistics experience to qualify as an expert witness. Senior laboratory personnel spend a considerable amount of their time in court, sometimes defending conclusions which may depend on analyses made by technicians or other personnel. The expert witness must not only be conversant with the legal and scientific basis of his testimony, but must also be prepared to give a detailed account of the experimental procedure, the statistical basis for the
ANALYTICAL CHEMISTRY, VOL. 47, NO. 3, MARCH 1975
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conclusions drawn, and the legal and scientific precedence for such conclusions (13).An example of the significance of cross-examination is provided by the current, close questioning of computer-based data and of automated analyses. The court may disregard the physical evidence, not on the basis of the measurements themselves, but because the witness is unconvincing in his presentation of the data because of his lack of background knowledge. Aspects of Symposium Proceedings
The symposium program was roughly divided into educational and technical aspects of forensic science, although these are, of course, very strongly interrelated. R. F. Turner of Michigan State University provided a perspective of the current problems in education and training, pointing out the historical aspects of the field which often provide precedents on which to base court testimony. He expressed the opinion that most courses being offered today are simply inadequate for the needs of the profession in that they do not include historical perspective. William McGee of Florida Technological University in Orlando carried out a very careful assessment of the current status of the profession before initiating a new undergraduate program in Forensic Science a t FTU. The curriculum for this program (Table I) is based on a heavy concentration in the physical sciences, with the balance of credit hours being taken up in courses concerned with the examination of particular classes of evidence. The instructors for these special topics are to be practicing criminalists, a valuable feature from the viewpoint of relevance. A very strong component of practical field experience is evident in this program and should be an integral part of any course which is intended to train professionals. The creation of a completely new course of this type is expensive; however, given the fact that most universities are capable of providing the basic science and legal courses, the only elements to be added are the special coverage of forensic science topics and the internship. Two criminalists (Richard Saferstein and Robert Epstein of the New Jersey State Police Laboratory) presented their experience in teaching introductory forensic science courses a t a number of’state and county colleges. The major problem in these courses is the poor academic backgrounds of the students, and Saferstein and Epstein thus teach basic science courses, using forensic topics as applications (Table 11). However, the technical criminalis320A
Table I. Undergraduate Forensic Science Program at Florida Tech nological University First Year
Fall
Biological Science Chemistry
Biology General
Communication Mathematics Social Science Second Year Chemistry
English Precalc.
University Studies Restricted Electivesa Physics Third Year Law 81 Legal Procedure Forensic Science Restricted Electives Social Science Statistics Summer Following Third Year Fourth Year Internship University Program English Restricted Electives Social Science
Organic Analyt. Microbiol. Physics
For. Anal.b Phys. Chem. Social Sci. Stat.
Winter
Spring
Botany General Gen. Lab Speech Calculus
Microb iol. General Analyt.
Organic Ana lyt History Irn m unology Physics
Organic Organic Lab Humanities Serology Electronics
Law Crrnnl. IC Phys. Chern.
Legal Proced. Crrnnl. I I Adv. Analyt
Computer Sci. Social Sci.
.
Cooperative Education Internship Internship Univ. Prog. Report Writing For. Sci. Social Sci.
Univ. Prog. For. Sci. Total Quarter Hours: 180
Restricted electives are approved courses in science, forensic science, legal procedure, or criminal justice. b Forensic Analysis Techniques. Crirninalistics. a
tic level is limited, and these courses cannot be regarded as a source of professional criminalists. Rather, they provide an appreciation of criminalistics for the police officer and layman and in this regard are important in advancing the status of physical evidence in the judicial process. Given the continuing tendency toward liberal education a t our undergraduate colleges, the need for specialized, technical training a t the graduate level is becoming evident. Although there are a limited number of graduate programs which are well regarded by the profession, these are too few to satisfy the increasing manpower and technical demands of the Nation’s criminalistics laboratories. Barry Karger, director of the newly established Institute of Chemical Analysis, Applications and Forensic Science (ICAAFS) a t Northeastern University in Boston, surveyed the situation in graduate education and research as regards forensic science. Northeastern University is part of a consortium of schools across the nation which was established by the Law Enforcement Assistance Administration of the Department of Justice (LEAA) to develop effective training and research programs in law enforcement. The educational and research goals of ICAAFS have been identified as a result of a careful study of the needs of the forensic science profession. A master’s program in forensic chemis-
A N A L Y T I C A L C H E M I S T R Y , VOL. 47, NO. 3, M A R C H 1975
try (Table 111) has been developed, and a doctoral degree program is planned. As can be seen from the table, these programs will contain a core of existing courses in science and law from a number of university departments and will be supplemented by specific criminalistics courses taught by experienced professionals. There will be a strong internship component in both programs, and all students will be involved in criminalistics research. The current research programs a t ICAAFS are concentrated in the applications of materials science and biochemical analyses to forensic science. Particular emphasis is being placed on rapid separation and identification methods which can be applied in the average criminalistics laborato‘Y, Further details of the goals of LEAA and of current and projected research programs were provided by Joseph Peterson (now a t John Jay College, CUNY); each research proposal is carefully reviewed by established, practicing forensic scientists to determine its feasibility and immediate and long-term usefulness to the profession. Among projects which have recently been funded are: A study of the availability and qualifications of scientific personnel and of regular proficiency testing (the Forensic Sciences Foundation) A study of the management and , evaluation of criminalistics laboratory
Table I I . Course Outline for Forensic Science Program Offered ir: ?dew Jersey State College System
LECTURES
I . Introduction
A . De+iii!ioii 3r.c history of forensic science B . Organizatior a n d services of o u r forensic laboratorj C. Function of :he forensic scientist 0. Lesal aspects of forensic science
The Nature of Physical Evidence 31 a n d class characteristics B. rile sigrlficance of probability in criminal evidence in~.cstiy:a!ioii I l l . Physical Properties of Matter A . U::i:s of me.3surement B . Determiriatioi- of mass, volume, a n d ternperatule C. Geiisity ?rid refractibe index IV. Forensic Properties of Glass and Soil V. Organic Analytical Techniques ~ . . r ~ , r ~ ~ , A. Tlieory a n d fcrerisx application of thin-layer arid H. Tb,eory 6na fciensic applications of spectrophoto:nt.try VI. Inorganic Pnalytical Techniques A. Theory jna forensic application of X-ray d i f f r a c r i v e f i i i C s h ' , < rroscopy, a n d neutron actibation V I I . Microscopy A. The theory a - ~ use l of the compound, steregsco9ii n : > j c,(;rr;:,f8%,'; m ic t osco pe 5, VIII. Forensic Examination of Hairs, Fibers, and Paint IX. Forensic Serology A Compos tiori of blood and semen B. A B 0 system C. Forensic chwacterization of dried blood a n d sern'zr: D. Principles 0' heredity X. Forensic Dwg Identification and Toxicology A , ?./I ic I o sco pic ;:n d ir,s t ru m e n ta I t ec 11 n i 1 LJ es for i df t i i f y i'2 aoused .:iruj:s B. The theory and application of the breatnaiyrer XI. Fingerprint 1di:ntification a n d Classification X I I . Firearm and Toolmark Identification X 111. Explosives and Arson Investigation A. T-ie cheqistry of conibustion 8. :-he detixtix~of exploside a n d gasolin2 residties 11.
A . 1,idividu
1
t ~ ~ , ~ ~
1
LABORATORY EXERCISES 1. !:lehsurcment of the density of glass by flotation
i. Particle riensity aistfibution of soil (density gradient ttr1)c.) 3. ramiliarlzat,on viith the cumpourid a n d stereoscopic ntic .4. hlicrosccjpic identification a n d compariso:-iof i'diis .ir.tf iia
5. 6. 7. 5.
Forensic prisJmpti,,e tests for blood arid seint-r!--~wi:cIe R.' i c r oscc pic i d en t i f 4 ca :io n of m r I j u a n a Color ar!d rricrocrystai tests for common!y aodsecl i i r : i c 5
Latent fiiigeiprint ider:tification prel)ar?tion a n d examination of c a s t s
q . The
a:;d nTci,i:
Table Ill. Curriculum for Master's Degree Program in Forensic Chemistry at Northeastern University Fall Quarter
QHn
Winter Quarter
First Year Instrumental Analysis
4 Crime Scene
Forensic Materials
2 Forensic
Administration of Crimina I Justice Biochemistry I
Investigation
Spring Quarter
2 Concepts in
Toxicology I
QH
Summer Quarter
QH
3 Forensic Chern- 4 In-Service istry TechTraining* niques II 4 Arson and 3 Explosives
Chemistry Techniques I 3 Seminar(or 1 Seminar(or Spring) Winter)
Elective Second Year Master's Paper Biometrics Electives
QH
2 Legal Aspects of Forensic
Science
2 Elective
1
Solid Samples
3 2
4 2 2
QH = quarter hour: 43 quarter hours of credit are required for graduation. demic credit I S given for in-service training.
operations (Planning Research Corp., L. W. Bradford, project director) Blood and bloodstain analysis (Aerospace Corp. and the Pittsburgh and Allegheny Crime Laboratory). These are programs to encourage wider implementation of existing techniques for dried bloodstain analysis (12) and to develop further techniques for the individualization of physiological fluids and dry fluid samples. Standard reference collections (NBS). Most criminalistics laboratories depend, a t least to some extent, on a reference collection of hair sam, , i , ) ples, color codes for paints, and the like. This project seeks to systematize these collections and to provide upto-date reference materials. Computerized information system. This is a study of the requirements for a nationwide computerized crime laboratory information system being carried out by the Project SEARCH Criminalistics Laboratory Information System Committee (CLIS). Many laboratories maintain files (e.g., of latent fingerprints) which are difficult to use because of time constraints imposed by inadequate classification schemes. Bradford and Samuel ( I ) emphasized the tremendous advantage of on-line computer file searches a t the local level, and the initial phase of identification could be made more efficient in this manner, with the final step of identification being performed by established comparative analysis techniques. Variant polypeptides in hair. This study is aimed a t the genetic typing of hair samples through analysis of the variants of structural proteins (Massachusetts General Hospital). Characterization and individualization of semen. Again, the goal of this research is to indiuidualize physiological fluid samples through genetic polymorphisms (Berkeley). LEAA is also currently involved in the establishment of rigorous criteria for evaluating new techniques and data for use in court, initially through a standing committee of leading judges, attorneys, and scientists. These studies would supplement the ongoing work of the Association of Official Analytical Chemists in establishing standard analytical procedures.
b
No aca-
ANALYTICAL CHEMISTRY
Applications of powerful materials science techniques to forensic science problems are becoming more widespread. Although the equipment is expensive, restricting its present use largely to regional and federal laboratories, there is the promise of further instrumental development to enable increased application a t the local level. Because of its capabilities in imVOL. 47, N O . 3, M A R C H 1975
321 A
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our uesteracus100 uears OF
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Atornspek H1550 ATOMIC ABSORPTION SPECTROPHOTOMETER We produced the first commercial atomic absorption spectrophotometer more than sixteen years ago. The Atomspek H I 550 is the latest in a long line of instruments it represents a lot of experience. Pages could be taken up in talking about its performance, its range of automatic facilities, the accessories, the readout systems, the sheer simplicity of use, and its beautiful styling.. . but what really matters is what it will do for you. To appreciate this you have to use it. CIRCLE 207 ON READER SERVICE CARD
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InfragraphH1200
One hundred years ago we made our first scientific instruments satisfying, initially, the esoteric demands of a specialised few.
INFRARED SPECTROPHOTOMETER
Soon the requirements of these few became the needs of many and so, over the succeeding years, we introduced a series of products which revolutionised the world of analytical chemistry. Amongst these, the first commercial instrument of their kind, were : The Wavelength Spectrometer The Fixed Adjustment Quartz Spectrograph The Infrared Spectrometer The Photoelectric Absorptiometer The Atomic Absorption Spectrophotometer all in their turn had a profound affect on the speed, the cost and the efficiency with which analysis was to be carried out and each became the forerunner of a vast new range of analytical equipment.
Spectrochemical analysis would not be the same without Rank Hilger.
RANKHILGER WESTWOOD'MARGATE KENTmCTS4JL. ENGLAND
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322A
ANALYTICAL CHEMISTRY, VOL. 47, NO. 3, MARCH 1975
The lnfragraph Mk3 double beam recording infrared spectrophotometer remarkable photometric accuracy for a low priced instrument bringing quantitative analysis of a very high standard within the scope of every laboratory. The instrument has a number of unique design features resulting from a completely new appraisal of what is really required from an infra red spectrophotometer. This fresh approach has brought about a system which is precise yet simple to use, compact yet able to accommodate very large samples. CIRCLE 208
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RankHilger are exhibiting at LABEX International,London, Stand E23 April 15th-18th A N A L Y T I C A L C H E M I S T R Y , VOL. 4 7 , N O . 3, M A R C H 1975
323A
Figure 1. Scanning electron micrograph records of firing pin impressions on two cartridge cases Casing on left recovered from river Sometime afler homicide committed. Casing on right fired from suspect weapon in laboratory. Because Of effects Of submersion, comparison by conventional microscopy vinually impossible C O U ~ ~ S01Y mry Juaa ana coworkern
proving the depth of field and its ready extension to energy dispersive analysis (EDA) of the elemental composition of surfaces, the scanning electron microscove is findine” useful anplication. The SEM mieht be used to detect erased serial numbers because the sample subsurface’retains some of the special properties caused by the initial serialization. Bullets, paint chips, “unknown substances,” and cement and d a s s fraements can be identified ranydly by combined SEM and EDA analysis. Fieure 1illustrates a comvarison (by Gary Judd of Rensselaer Polyt echnic Institute and coworkers) of a test cartridge case with a sample Vvhich had been recovered from a river Some time after a homicide had been ,---;++..a . Tl lLl r :-A:.... :- Annil. $.. C”l...ll.rrru surface features hetween the test and sample is easily overcome by SEM, and analysis of the persistent features enables identification. Donald Polk and Bill Giessen of ICAAFS have devised a powerful tagging system for guns which employs laser drilling of up to 10 readily deci-
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open evidence file of more than 25,000 specimens which dates hack to the 1930’s).Among the techniques holding promise for improving the efficiency of bullet identification is the SEM, coupled with a computerized data base. Fourier transform techniques might also he applicable, although the significant differences between the surface detail of the deformed evidence and test samvles are difficult to resolve. The examination of susvected arson debris is aimed a t establishing the use of incendiary substances (gasoline, kera&ne, alcohol) with criminal intent . If the article bas been packed in an a ir-tight container, headspace samplinj5 frequently enables identification
of the volatile components by gas chromatography. Steam distillation followed by GC is often useful for the remainder. However, Cecil Yates of the FBI Laboratory pointed out that adulterants such as plasticizers wreak havoc with gas chromatographic columns, and it is difficult to maintain a reference collection of incendiary substances because of frequent formulation changes by manufacturers. There is considerable potential in the use of high-pressure liquid chromatography in the fingerprinting of arson debris. [Recent work a t Waters Associates ( 1 4 ) has shown that gradient elution. reverse-phase chromatography is capable of separating and quantitating the additives in petroleum samples and that high-pressure gel permeation chromatography is suitable for the separation and identification of lowmolecular-weight plasticizers such as phthalates.] Two other techniques are worthy of special mention in that they offer the possibility of wide analytical application of single instrument systems a t the local level. The first is differential scanning calorimetry, which Hall and Cassel of Perkin-Elmer Corp. have shown to he diagnostically powerful in the individualization of %-in. lengths of hair and other polymers. Single strands of hair and clothing material comprise an important class of evidence material which often defies conventional microscopic identification. The advantage of differential thermal methods is that they allow the identification of man-made fibers: each sample has a thermogram which exhibits characteristics of a specific processing history (15).A sample size-
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which is normally that required for just one digit of a conventional serial number (Figure 2). The great advantage of this system is that the identification can be situated in an inaccessible part of a gun so that erasure would require virtual destruction of the weapon’s action. The manufacturing cost of serialization by laser drilling has been estimated a t only $0.05 per gun. The laboratory caseload of recovered bullets is usually very large (Detective Johnson reported that in 1973 the New York City Police Department processed 16,184 cases involving 16,850 individual firearms, using an 3241
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Serial number 5383158068 on right can be read by reference to grid formed by holes at extreme left and right
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ANALYTICAL C H E M I S T R Y , VOL. 47, N O .
3, M A R C H 1 9 7 5
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Figure 3. Thermalmechanical analysis thermogram of single fiber of untextured cellulose triacetate. Thermogram reflects processing history of sample Courtesy of Perkin-Elmer Corp.
limited test schedule illustrating the thermalmechanical analysis (TMA) and differential scanning calorimetry (DSC) capabilities of a modular instrument system is illustrated in Table IV. Figure 3 shows a TMA thermogram of a single fiber of untextured cellulose triacetate; the normal thermal expansion of the material a t low temperatures is followed by contraction as water is lost above 100’. The 5%)expansion associated with the glass transition a t 180’ is followed by contraction before melt ing/decomposition, properties which are diagnostic of triacetate; in particular, the transition temperatures are characteristic of individual samples. Other major
Figure 4. Identification of rayon, cotton, and wool by DSC in inert atmosphere DSC profiles characteristic of individual samples. Conditions: range, 10 rncal/ sec, full scale: atmosphere, NP;scanning rate, 40°C/min Courtesy of Perkin-Elmer Corp.
classes of fibers (polyacrylonitriles such as orlon and acrilon) and rayon and cotton show no distinctive thermal features up to 300°, but “fingerprints” can still be recognized in the absence of oxidative decomposition by heating the sample in an inert atmosphere (Nz, argon) (Figure 4). A second technique which holds considerable promise for operationally simple and widespread use in criminalistics is photoluminescence, which may be defined as the light emitted by a sample in the 300-700-nm region on excitation with UV (190-380 nm) radiation. Useful analytical parameters are: the emission and excitation spectra (the latter is defined as the variation of luminescent intensity at fixed wavelength as the wavelength of the excitation source is varied; the decay time of the luminescence once the excitation source has been extinguished; and the quantum yield of emission. The analytical advantages of these methods are substantial: Highly selective-absorption, emission, and lifetime parameters of evidence and test specimens must all match Highly sensitive (1 ng for efficient emitters) *Often nondestructive *Inexpensive *Often do not require preseparation of the sample. The current research a t Aerospace Corp. (P. Jones) aims a t extending the capabilities of the conventional qualitative inspection of evidence for forgery, the location of body fluid stains, spots in paper and TLC chromatography, and the usual comparison of oils, greases, paint chips, and glass frag-
ments, to quantitative analysis of a wide range of forensic materials. Luminescence decay curves (e.g., of aromatic hydrocarbons in polymer matrices) are nonexponential because of the anisotropic environment of the solute (16),and the sensitivity of the luminescence of a molecule or atom to its microenvironment has been shown to be extremely valuable in the individualization of clue material. Luminescence decay properties can be used to detect semen (17),which is a difficult problem using conventional colorimetric or microcrystal formation techniques. Electrophoresis (18) enables the separation of seminal acid phosphatase from vaginal fluid, and the former can be positively identified even in the absence of spermatozoa (which is the case in about 50% of the samples examined). The technique is also applicable to gunshot residue analysis: low-temperature (77OK) luminescence from chlorocomplexes of lead (11) and antimony (111) a t 276, and 250 and 300 nm, respectively, allows simultaneous detection of these elements in gunshot residue a t the 110-ng level in less than 30 min. The analysis of gunshot residues was the subject of two other papers a t the symposium. Edgars Rudzitis (Illinois Bureau of Investigation) and Maurice Wahlgren (Argonne) have improved the sample capacity and statistical evaluation of neutron activation analysis, and William Kinard and Donald Lundy (Bureau of ATF, Washington) have shown that flameless atomic absorption measurements give comparable data a t the microgram level for arsenic and antimony residues. Photoluminescence analysis
A N A L Y T I C A L CHEMISTRY, VOL. 47, NO. 3, M A R C H 1975
325A
further improves the sensitivity by three orders of magnitude, with analysis times comparable to flameless AA. These latter methods may be more applicable to the local laboratory than is NAA and should lead to much wider local utilization of residue analysis. The refractive indices of 143 glass samples from California criminalistics laboratories have been measured by Peter Jones and his coworkers: about 50% of these samples had refractive indices in the range 1.5160-1.5180, making conventional comparison virtually impossible. Thirteen of these samples phosphoresced with broad bands a t 540 and 730 nm; however, a t fixed excitation wavelength and excitation source intensity, the different ratios of the peak absorbances allowed 12 of the 13 samples to be distinguished. Photoluminescence is clearly a very powerful, yet simple technique for the individualization of glass samples. The sensitivity of tryptophan and tyrosine emission to the microenvironment is a potential means of individualizing single strands of hair (19). Hair strands from eight light-colored individuals which could not be distinguished by conventional microscopic techniques were excited a t 250 nm and 77OK. Although phosphorescence decay characteristics did not differ sufficiently to allow clear distinction between samples, individualization was still possible on the basis of their distinct phosphorescence spectra (Figure 5 ) . [The availability of relatively inexpensive spectrofluorimeters that give spectra which are automatically corrected to eliminate artifacts owing to variations of the excitation source intensity and detector response as a function of wavelength is an important recent development in fosnsic analysis. The corrected excitation spectrum is identical to the absorption spectrum but with a thousandfold increase in sensitivity for fluorescing substances such as quinine and morphine (as pseudomorphine). A fluorescent substance can thus be positively identified by comparison with standard absorption spectra (rather then uncorrected fluorescence spectra which depend on the particular instrument on which they were measured), and the analysis of mixtures of very dilute fluorescent materials can be made by conventional techniques without the need for separation. The only requirements would seem to be that the absorbance of the solution be less than ca. 0.05 in the 200-700-nm region, and that the substance(s) have a fluorescence peak a t a longer wavelength than the solvent spectral cutoff.] An elegant example of the applica326A
tion of a well-established technique (thin-layer chromatography), backed by a comprehensive reference collection, is provided by the ink identification capability of the Bureau of ATF (Richard Brunelle, chief, Identification Branch). By use of TLC with a comparatively small range of solvent systems, inks can be readily identified as microsamples which leave the questioned document intact for other analyses (e.g., of handwriting). Ink formulations generally contain enough components to allow direct, qualitative comparison with library data, especially when the chromatogram is examined both visually and under ultraviolet light. This technique has been accepted as definitive evidence by the courts in quite a number of recent cases. Manufacturers have been very cooperative in providing samples of commercial inks, and ATF is trying to encourage more frequent formulation changes and specific tagging to allow more precise dating of questioned documents.
Genetic Markers Over the past few years there have been several notable advances in the applications of forensic serology in the evaluation of important classes of clue material such as blood and seminal stains. The goal of workers a t the FBI and Pittsburgh and Allegheny County crime laboratories is to identify genetic markers whose population frequencies have been firmly established. These markers are inherited independently of one another, and a marker profile will permit a mathematical probability of uniqueness to be calculated. Obviously, the greater the number of markers, the higher is the probability of a unique identification ( 5 ) . Three classes of blood constituents are useful for the establishment of markers, namely, the blood grouping and typing antigens, polymorphic enzymes, and polymorphic proteins (12). The conventional AB0 and MN systems have well-established frequencies. The Rh system, which is not so widely used as the other two, has a five-component antigen system giving rise to eight agglutinogens. Useful data for the British population have been summarized by Williams ( 5 ) .The Pittsburgh group has succeeded in shortening the AB0 blood grouping of just three bloodstained threads to 45 minhample. Electrophoretic separation and identification of typable isozymes are gradually gaining acceptance in North America. However, the typing of evidence depends on careful control of experimental procedures and the availability of reliable statistical data. Recent work a t the FBI Laboratory in Washington by C. G. McWright and
A N A L Y T I C A L C H E M I S T R Y , VOL. 47, NO. 3, M A R C H 1975
A, nm
Figure 5. Phosphorescence spectra at 77'K for hair of two different individuals at three different excitation wavelengths Significant variation of phosphorescence intensities evident on changing excitation from 250 to 350 nrn 350 nm. - 250 nm; - 300 nm;
--
-.-
Courtesy of Peter Jones
coworkers has been focused on the establishment of optimum conditions for the electrophoretic typing of erythrocytic acid phosphatase (EAP) phenotypes. A study of the distribution of five EAP phenotypes in 137 randomly selected Washington, DC, residents gave results in good agreement with those of Giblett and Scott (20). The FBI studies indicate that the incidence of EAP phenotypes is not associated genetically with blood groups ABO, MN, and Rh. The third main class of genetic markers in blood consists of the polymorphic proteins, which include hemoglobin and the haptoglobins. Hemoglobin typing is useful for the identification of fetal and negroid blood (21).Peptidase A and glutathione reductase have also been found to exhibit polymorphism in negroid blood, with little or no variation in caucasians. The Pittsburgh group is further exploring typing schemes in the Gm and Inv immunoglobins (so far, 23 Gm and 3 Inv types have been found, but success is predicated by the availabilit y of antisera) and is also applying radioimmunoassay to quantitate testosterone and estrogen in dried blood to determine the sexual origin of very small samples.
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A N A L Y T I C A L CHEMISTRY, VOL. 47, NO. 3, M A R C H 1975
P(:M and lactate dehydrogenase (LDIH) may he developed on the same zym()gram. LDH-4 and LDH-5 pheno. type:s are elevated in menstrual hloodstain s even after two weeks. A new hand , currently laheled LDH,, appear:3 between LDH-3 and LDH-4 as a .nllli of spermatogenesis and can be .,,,,t detected even when semen is absent in the sample (22).Current work indicates that at least five constituents of seminal fluid can he electrophoretically separated and antigenically introduced into rabbits, and that acrylamide electrophoresis of acid phosphaswabs tase, AP, is useful .. when .vaginal . I .. are being tested for seminal fluid; however, it is still only a presumptive test until the specific source of the A P can he identified. Further development of simple and accurate typing methods is clearly an important aspect of current criminalistics practice.
Figure 6. GC separation of trimethylsilyl derivatives from her.
oin sample 1. Morphine-TMS 2, codeine-TMS 3. oB-monoacetylmorphine-TMS: 4, ecetylcodeine: 5 , heroin. Direct Chromatography of samples under comparble experimentalconditions does not res0Ive acelyicodeineand @-monoacetylmarphine Courtesy of Stanley Soboi and Albert S p e m
Drug Identification and Analysis
Drug identification and analysis is a dominant feature of the caseload of many criminalistics laboratories. Research concerned with the estahlishment of standard methods of identification and quantitation of drugs, drug metabolites, and toxins continues to be an active area in forensic science (23).Advances in this area are thus of great interest to criminalists, and papers on this topic gave rise to lively discussion at the symposium. Forensic toxicology has been defined by Finkle (4) as the evaluation of the harmful effects of exogenous substances on living systems in the medico-legal context. The three major caseload areas which dominate forensic toxicology are: Illegal use of drugs * Broad, criminalistic investigations -Postmortem cases. Definitive interpretation of the evidence is demanded by the courts in all cases. As a result, an increasingly sophisticated range of analytical techniques is being applied to meet the legal requirement for absolute quantitation of even micro- and picogramfml levels of drugs and drug metabolites in physiological samples. The methods of widest potential application are based on separations by gas or high-pressure liquid chromatography coupled with mass spectrometric detection. Ahsolute identification of very low levels of drugs, drug metabolites, and toxins is then possible through comparison with standard mass spectra (24). The establishment of illicit narcotics sources is of particular interest to the Drug Enforcement Administration, where workers in the Special Testing and Research Laboratory (S. P. Sohol, chief) have investigated direct and derivative GC methods for
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(6) Chem. Eng. >..-., ~._,_”._.,. the fii.5~..k ingotdrug exhibits. ( 7 ) R. H. Fox and C. L. Cunningham, Adulternnts in heroin samples include “Crime Scene Search and Physical monuacet).lmorphine, acetylsodeine, Evidence Handbook,” US.Department opium alkaliiids rintroduced during of Justice, 1973;J. L. Peterson, “Utilization of CriminalisticsServicesby production, and quinine, prrx‘aine, the Police-An Analysis of the Physical methnpyrilene. and various sugars (inEvidence Recovery Process,” National troduced at the street IeveI~.‘l’heidenInstitute of Law Enforcement and tiiicntion oias mnnq ctinstituenrs as Criminal Justice, 1972; G. B. Stuekey, “Evidence for the Law Enforcement possihle is the goal in the “fingerprintOfficer,” 2nd ed., McGraw-Hill, New ing” of drug samplrs. DerivatiLation York, NY, 1974. (involving treatment with N,O-his(8) T. Kondis, Renaissance Pittsburgh, p ttrimet h ~ l s i l y l ) - r r i ! l i i ~ , r o ~ i ~ e t ~ m i d e ~ 28, September 1974. (9) R. R. Ruch, V. P. Guinn, and R. H. gives clean separatiiin of morphine, Picker, N u l . Sci. Eng.,20,381 (1964); codeine, Ofi. m~,n(,a~i,t).lniorphinr, ac V. P. Guinn, R. P. Hackleman, H.R. etvlwdeine, and heroin in ahnut 2U Lukens, and H. L. Sehlesinger, USAEC min (Figure 6). The minor constituReport GA-9882, Department of Commerce, Springfield,VA, 1970. ents (morphine and rodt.int.1 can he (10) G.D. Renshaw, CRE Report 103, detrctrd ut the 15-23-n:: levrl. These Home OfficeCentral Research rhromntographic techniques have Establishment, Aldermaston, Berks., heen surcessfdly used tbr court tt:itiEngland, 1974. (11) R. L. Brunelle and M. J. Pro, J. Assoe. mony and arc. rrpreseutative u i a Offic. A n d Chem., 55,823 (1972). mujur current emphiiiii on developing (12) B. J. Cullifard, “The Examination new meth(rddog) i n rriminalistici. and Typing of Bloodstains in the Crime The Atlantir Vir? symposium p11Laboratory,” National Institute of Law Enforcement and Criminal Justice, per*, which will be piililishi~lshortly Washington, DC, 1971. as a wlurne in the “A(.’S Symposium (13) A. A. Moenssens, R. E. Moses,and F. Series,” will serve a i il u;etul guide t t i E. Inbau, “Scientific Evidence in current ediicittional and scientific Criminal Cases,” Foundation Press, Mineola, NY, 1973. progress in hr(&c science. (14) W. A. Dark, Waters Associates, Milford, MA, private communication, lq7d
..
”. . -. H. Samuel, “Law Enforcement-Science and Technology,” Vol 111,p 465, Academic Press, New York, NY, 1970. (2) “Task Force Report: Science and Technology,” President’sCommission on Law Enforcement and Administration of Justice, Washington, DC, 1967. (3) J. M. English,Anol. Chem., 42 (13), 40A (1970). (4) B. S. Finkle, ibid., 44 (4),18A (1972). (5) R. L. Williams, rbid., 45 (131,1076A . (1973). (1,
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(l$W. M. S. Philp, J.ForensieSei., 17, 132 (1972);W. P. Brennan, “Therm. Anal. Appl. Studies,” 6, Perkin-Elmer Corp. Publication TAAS-6, 1972. (16) P. F. Jones and A. R. Galloway, J. Chem. Phys., 51,1661 (1969). (17) P. F. Jones, A. R. Calloway,D. J. Carre, and S. Siegel, J. Forensic Sci. Sac., in press. (18) E. G.Adams and B. G. Wraxall, Forensic Sci., 3,57 (1974). (19) S. V. Konev, “Fluorescence and Phosphorescence of Proteins and Nucleic Acids,” p 147, Plenum Press, New York, NY, 1967.
ANALYTICAL C H E M I S T R Y , VOL. 4 7 , N O . 3, M A R C H 1975
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Somerimes ir’s more imporronr ro Iknow rhe composirion of the residuol and evoived gases in a high vocuum sysrern rhon [he raral pressure.cvcp new CVC ProducrsInc..meering rodoy’sneeds rorol r J wirh =IeS Ond inexpensive AIG-50 measures @ pressure and individual mosspeoks. And service. ir’s os eosy ro use as on ordinary ionizolion gouge.
(20) E. R. Giblett and N. M. Scott, Amer. J. Hum. Genet., 17,425 (1965). (21) W. H. P. Lewis and H. Harris, Nature, 215.434 (1967). (22) S. J. Baxter,Med. Sei.Low, 13 (31, 155 (1973). (23) J. M. Singh and H. Lal, Eds., “New Aspects of Analytical and Chemical Toxicology,” Val 4 of “Drug Addiction,’’
Stratton Intercontinental Medical Book Corp., New York, NY, 1974. (24) B. S. Finkle. D. M. Taylor. and E. J. Banelh, J. Ct (1972).
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Geoffrey Davies is a n assistant professor of chemistry and a Faculty Fellow in the Institute for Chemical Analysis, Applications and Forensic Science at Northeastern University. In 1966 he received his P h D degree from Birmingham University, England, for work in inorganic chemistry. He then spent two years as a n NIH Fellow a t Brandeis University and one year as a research associate in chemistry at Brookhaven National Laboratory before taking up a n IC1 Fellowship at the University of Kent, England, from 1969 t o 1971. Since joining Northeastern, Dr. Davies has been involved in undergraduate and graduate teaching in chemistry and has formed a research group which is working on a variety of projects in analytical and physical-inorganic chemistry. His work in ICAAFS is concerned with the establishment and operation of undergraduate and graduate programs in forensic chemistry and with the application of chemical technology to problems in forensic science.
