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10 Examination of Controlled Substances
What is your practical training and experience in this field?
What factors qualify you as an expert in the field of controlled substances?
Are you familiar with procedures used to test this substance?
How many times have you tested this substance?
Have you previously testified as an expert in any court of law?
(a) How many times?
(b) In what courts?
10. Why do you consider yourself an expert in the field of forensic chemistry?
The following court-related questions are provided for informational purposes only. They are intended to provide you
with a glimpse of an actual trial setting.
Describe the differences between natural drugs and synthetic drugs.
Discuss the difference between an analog and a precursor.
Could a precursor be an analog of a controlled substance?
Define an isomer and list three types.
List four physical effects of drugs use.
Define physiological effects of drugs use.
What is the difference between psychological dependence and physical dependence?
What differentiates synthetic drugs from natural drugs?
What is the difference between a synthetic drug and a designer drug?
List two routes of administration of drugs.
Describe the difference between potency and physical dependence.
Describe the three stages of substance identification.
Name three schedule III drugs.
What is the usable quantity of morphine?
List three characteristics of analogs.
Abadinsky, H. Drug Use and Abuse: A Comprehensive Introduction, 6th ed.; Brooks/Cole: New York, 2008; chaps. 1 & 7.
California Law: California Health and Safety Code. http://www.leginfo.ca.gov/.html/hsc_table_of_contents.html (accessed April 2009).
Doweiko, H.E. Concepts of Chemical Dependency, 7th ed.; Brooks/Cole Publishing: New York, 2009; chap. 4.
Faupel, C.; Horowitz, A.; Weaver, G. The Sociology of American Drug Use, 2nd ed.; Oxford Press: New York, 2009; chaps. 1 & 3.
U.S. Drug Enforcement Agency. http://www.usdoj.gov/dea/pubs/csa.html (accessed April 2009).
Documentation is the foundation of science as well as the hallmark of a sound legal system. It is often said, “If it is not written down it does not exist.” It is absolutely essential to properly document each step of any examination process.
Investigators and forensic personnel are required to submit evidence that appropriate tests were performed and that the
results presented in court are (in fact) the test results observed either in the laboratory or at the crime scene. Memory is no
longer considered either reliable or trustworthy, and proof through documentation has become the standard for acceptance.
Scientific results must be reproducible before they are recognized by the scientific community. Documentation provides
a mechanism for peer review, replication, and research advancement. Examination procedures performed on physical evidence must be properly recorded, along with results. The results must support and justify the conclusions presented in the
final report. More importantly, an expert in the same field should agree with the report’s conclusion. The reviewer may have
a different opinion, but he must agree that the records support the conclusion.
Documentation procedures used in forensic laboratories generally have three common components, each with its own
requirements. They are chain of custody, case notes, and the case report.
Chain of Custody
The chain of custody is a document (or series of documents) that tracks the location of evidence from collection (crime
scene) to final disposition (court). The chain of custody maintains the integrity of evidence through accountability. It requires
the examiner to document when, and from whom, the evidence was initially received and when, and to whom, the evidence
was transferred. It is generally accepted that the evidence is in the examiner’s sole care and custody during this period. The
documentation procedure usually requires an official form with supplemental notations in the examiner’s working notes.
The details of examination procedures are rarely addressed in the chain of custody. Typically, they include the date and
time of an examination, the identity of the person performing the examination, and the date and time the evidence was transferred, returned, or released.
The law does not stipulate categories of transfers. Therefore, the transfer of evidence within a laboratory is documented
in the same manner as a transfer of evidence between laboratories.
The early use of mass spectrometry illustrates the importance of chain-of-custody documentation. The mass spectrometer
is a highly specialized analytical instrument. The analyst had to rely on the operator to perform this specific examination and
often had no direct knowledge of how the evidence was handled once it was transferred. Although a forensic chemist could
interpret the resulting data and knew the theoretical basis of the instrument’s operation, they could not provide direct knowledge that every procedure was followed. As a result, chain-of-custody documentation was required.
J.I. Khan et al., Basic Principles of Forensic Chemistry, DOI 10.1007/978-1-59745-437-7_6,
© Springer Science+Business Media, LLC 2012
Methods of documenting case-related information are contained in the laboratories’ standard-operating-procedures manual.
However, these manuals often provide only a list of requirements and rarely address the details of recording information.
Case notes may be either very simple or highly detailed, depending on the individual practice of the analyst. Regardless, they
must be accurate and comprehensive. Incomplete case notes reflect negatively on the analyst and can cause complications at
trial. There is a notable difference between incomplete notes and messy notes; incomplete notes lack accuracy, while messy
notes are simply difficult to read.
When documenting evidence, remember the old saying, “A picture is worth a thousand words.” It is a good practice to
take pictures of unusual evidence (Fig. 6.1). If an item contains a large number of specimens, each piece must be individually
documented (Fig. 6.2). It is often helpful to use abbreviations in case notes for simplicity and clarity, but do not overuse them
(Fig. 6.3). Be sure abbreviations, if used, are from an approved list, and never use those that are self-created or ambiguous.
If an error is discovered in your notes, simply cross out and initial the error, and date and initial the correction (Fig. 6.4).
Never obliterate errors or use whiteout; this may cause suspicion (Fig. 6.5).
Fig. 6.1 Pictures always assist in
understanding a crime scene. (a)
A single picture is often better
than pages of descriptive notes.
(b) Samples of cocaine pricks. (c)
An imprint on a cocaine brick.
6.3 Case Notes
Fig. 6.2 Note how useful it is
when each item is described
separately. This minimizes
Fig. 6.3 Examples of notes with
Fig. 6.4 Properly made
corrections are initialed and
dated to maintain the integrity
of the documentation process.
Fig. 6.5 Example of unacceptable corrections: material is
obliterated, undated, and not
The case notes are the second component in the documentation process. They consist of handwritten notes, worksheets,
examination results, analytical data, and administrative paperwork. The case notes serve two functions; first, they document
all aspects of the examination process, and second, they are used as references by the examiner for report writing and preparation of testimony.
Case notes are a complete record of all case activity in the criminal-justice system. Although the final report will provide
a summary and conclusion of the entire process, the history of the case is contained within the pages of the case notes.
In recognition of the fact that examinations produce more information than that contained in laboratory reports, regulatory and accreditation agencies require that case notes be maintained. Also, peer review requires the availability of information (case notes) used to formulate scientific opinions.
The American Society of Crime Laboratory Directors (ASCLD) criteria states that a case file must be generated for each
case and that each file must be uniquely identified. The International Organization for Standardization (ISO-17025:2005)
criteria are slightly more specific; it details the type of information that must be included in technical records. Surprisingly,
accreditation agencies, such as ASCLD and the ISO, do not regulate the contents of the case files.
The following list contains items commonly found in a case file.
• Copy of all final reports
• Copy of all evidence-submission forms
• Copy of all relevant chain-of-custody documents
• Itemized description of the type and condition of the packaging when received (sealed vs. unsealed)
• Itemized description of evidence received
• Detailed description of the items examined
• Description of the examination(s) performed
• Handwritten notes on examinations performed with observations and evaluations, to include but not limited to:
– Original sample weight
– Results of wet chemical tests
– Results of instrumental examinations
– Sample-preparation techniques
• All original charts, graphs, photographs, photomicrographs worksheets, analytical data or any other type of laboratory
– Photocopies are an acceptable replacement for original information that is not in a form conducive to storage in the case file
• Copies of written reports related to submitted evidence
• Correspondence or telephone notes related to the case
Each page of the case file is required to have additional information as a quality-assurance measure. These items are:
• The agency’s unique case number
• The forensic chemist’s handwritten signature or initials
• The date each page was generated
• The page number and total number of pages
– Machine-generated dates, record numbers, and pagination are acceptable.
Accreditation agencies do not regulate the format of case files. Laboratory-approved forms, official police reports, and
instrumental data sheets are usually provided. The format of handwritten notes (case notes) may, or may not, be specified
in the laboratories standard-operating-procedures manual.
Handwritten notes have two common formats; one is simply a series of notations on a blank sheet of paper, and the other
consists of preprinted worksheets designed to streamline the documentation of repetitive testing procedures. Regardless of
format, each page of notes should contain the examiner’s initials, the date of the examination, the case number, exhibit number, page number, and the total number of pages (including pages of instrumental data).
Legibility is a key component of handwritten notes. If shorthand is used, it must be defined and clarified in order for the
peer-review process to be effective. Ambiguity may lead to misinterpretation.
Whether or not case notes are admissible as evidence or are subject to discovery is an ongoing debate. Some laboratories feel
that case notes are the protected, personal property of the forensic chemist. They will go to great lengths to prevent their
discovery, citing the case notes are summarized in the final report. Others will openly release case notes upon request as a
supplement to the final report. The case-note dissemination policy is ultimately regulated by local statutes, case law, and
individual laboratory policy.
The case report is the final component in the documentation process. This report contains a summary of examination procedures, the case notes, analytical data, and the professional opinion of the examiner. This report should be a stand-alone document requiring little, if any, clarification from the examiner.
Format and Content
Generally, case-report formats are determined by individual laboratories; however, most formats are based on the criteria set
forth by the American Society of Testing Materials (ASTM), the ISO 17025, or ASCLD. Regardless of format, each case
• Name of the laboratory performing the examination
• Case file number
• Name of the individual requesting the examination(s);
• Examiner’s name
• A list and description of the evidence submitted for examination
• Description of the examination(s) performed
• Results of the examination
• Chain of custody of documentation
As previously stated, the case report should be a stand-alone document. While this is true for some sections of the report,
it does not necessarily apply to the entire document. For example, courts often require additional testimony to clarify the
examination description and result sections, while the administrative segment may be accepted as written in the report. Some
formats separate all the sections, while others do not; for example, a description of the testing process could be included in
the results narrative. In either case, the reader should be able to confirm the identity of the controlled substance along with
the testing procedures used to make that determination.
Below are two examples of different formats used to report examination results.
1. White powder
2. Plant material
1. Contained cocaine, a narcotic drug. Substance mass 1.32 g. A usable quantity.
2. Contained marijuana. Substance mass 6.29 g. A usable quantity.
1. Item 1: A paper packet containing a white powder.
2. Item 2: A plastic bag containing a green leafy plant material.
1. Examination of Item 1 using wet chemical tests, microcrystal tests, gas chromatography, and infrared spectroscopy concludes that Item 1 contained a usable quantity of cocaine. The total substance mass was 1.32 g, which is considered a
usable quantity. Cocaine is defined as a narcotic drug under ARS 13-3401.20.
2. Examination of Item 2 using microscopic and wet chemical techniques concludes that Item 2 contained marijuana. The
total substance mass was 6.29 g, which is considered a usable quantity. Marijuana is defined as a narcotic drug under ARS
Example One provides the information in a basic format. The reader can quickly identify each exhibit, the quantity of
substance, its classification under governing statutes, and a case-law opinion on the amount of substance seized. However,
information justifying the examiner’s conclusions is not included. This omission may lead to an unnecessary and time-consuming court appearance.
Example Two represents a more complete report. It not only contains the same information as example One but also
includes a description of the tests used to justify the examiner’s conclusions. This addition may not require a court appearance by the examiner.
Describe the process of chain of custody.
What are the advantages of chain of custody?
Please explain to the jury the procedure of evidence receipt.
Name two organizations that regulate case-documentation procedures.
List seven items often included in a case report.
What information is commonly included in case notes?
What do you do with the case notes after completion of the analysis?
Describe the difference between incomplete notes and messy notes.
Is it possible to alter case notes? Explain.
Describe the process of correcting errors found in case notes.
What activity initiates evidence analysis?
What did you do with the evidence after the analysis is complete?
The American Society of Crime Laboratory Directors. http://www.ascld.org/ (accessed May 2009).
International Organization for Standardization (ISO). http://www.iso.org/iso/home.htm (accessed May 2009).
Chemical-screening methods are presumptive tests commonly used to initiate the process of substance identification. These
simple reactions cannot identify the substance without uncertainty; however, they do provide preliminary confirmation of the
presence of either a particular functional group or a generic molecular structure. Chemical-screening tests produce a distinct
color when the reagents are mixed with compounds containing a specific functional group. Although not highly specific,
these preliminary tests will determine which subsequent method is best suited to identify the substance.
Unfortunately, it is not uncommon for two people to describe the same color in different terms. The interpretation and
reporting of colors can be influenced by the concentration of the sample, the presence of diluents and adulterants, the age of
the reagent, and test reaction times. Also, color transitions and instabilities may result in the formation of multicolored complexes. The subjective and inconsistent nature of color formation and reporting may call into question the use of color screening as a viable method, especially in the area of controlled-substance examinations. This fact should be recognized and
allowances made, and the forensic chemist must be prepared to justify reported conclusions.
Chemistry of Color Formation
Visible light (white light) contains a mixture of wavelengths in the electromagnetic spectrum, ranging from approximately
350 nm (violet) to 750 nm (red). If some of these wavelengths are removed from white light, it is no longer observed as
white. All matter is composed of atoms and/or molecules. If an object is colored, the atoms or molecules absorb a portion
of white light, thus removing it from the visible range. The observed color of the object is not the light that is absorbed; it
is the remaining wavelengths that are reflected (not absorbed). For example, if red light (~750 nm) is absorbed by an object,
it is removed from white light and the object appears green (a mixture of the reflected wavelengths). The ability (or capacity) of a substance to absorb (or not absorb) light depends on its chemical properties, i.e.; molecular structure, bond energies, electron arrangement, etc. A change in chemical properties can result in a change in color. A chemical reaction is any
process that results in a chemical change. Therefore, a chemical reaction will produce different colored products if it
changes the light-absorbing capacities of the reagents (starting material). Color-screening tests produce distinct colors by
changing the light-absorption properties of controlled substances. These changes are often directly related to a small
change in either the orientation or the location of electrons in the structure. For example, primary amines will react differently than secondary amines when mixed with specific reagents. Tertiary amines may or may not react with reagents that
produce a change in primary and/or secondary amines.
The location of electrons in the three-dimensional structure of a molecule is one of the factors that determine color. Colorscreening reagents utilize four general mechanisms to produce a characteristic color change; all are based on changing either
the location or the orientation of electrons. A characteristic color is produced when:
J.I. Khan et al., Basic Principles of Forensic Chemistry, DOI 10.1007/978-1-59745-437-7_7,
© Springer Science+Business Media, LLC 2012
1. A screening reagent(s) removes an electron directly from the test compound.
2. A screening reagent(s) adds an unpaired electron directly to the test compound.
3. A screening reagent(s) complexes directly with the test compound, resulting in the addition of an unpaired electron.