Forensic Chemistry Laboratory Manual
Purpose
This manual details applied analytical procedures for a one-semester Forensic Chemistry laboratory course.
Scope
This manual is intended for upper-level undergraduate students pursuing a degree in chemistry, biology, or biochemistry. It is expected that these students have demonstrated competency in quantitative analysis and organic chemistry.
Introduction
Background
Forensic chemists may utilize a wide variety qualitative or quantitative methods to identify unknown substances found at a crime scene or in biological matrices. There are many types of evidence that may require characterization, identification, or quantitation such as drugs, ignitable liquid residues, inks/dyes, energetic materials, and trace materials like glass, plastic, fibers, etc. Many laboratories and/or analysts often only routinely work within subfields of forensic chemistry such as drug chemistry, toxicology, fire debris, etc. depending on their specialty. Many of these subfields use similar instrumentation, but the sample preparation, instrumental methods, data analysis, uncertainty, and reporting requirements can vary.
Design
This manual contains a major focus on industry standard techniques and instrumentation used for drug chemistry and toxicology with brief introductions to other types of samples and analyses. Where possible, these exercises are designed to simulate those performed in a forensic laboratory. Other exercises are designed to reinforce some critical skills and concepts relevant to working in a forensic laboratory such as accurate solution preparation, creation of a calibration curve, etc.
Most of these exercises were written for students attending lab twice per week. Some exercises are designed for all students to prepare samples or conduct presumptive testing in the first lab period and conduct confirmatory testing during the second lab period. Others may be performed on a rotating schedule to minimize time spent waiting on instrument availability. The exercises may be altered depending on the class size, schedule, instrumentation limitations, or supply availability.
Lab assignments
Some exercises include pre-lab reading and/or assignments. These should generally be completed before attending lab unless otherwise instructed.
Lab reports will be prepared for all exercises. A template is provided in the appendix that blends the requirements for a ‘‘, a ‘‘, and a more traditional .
Required Materials and Safety Reminders
Each student should acquire the following prior to the first lab meeting.
- A lab notebook or composition book
- NOT spiral bound
- NOT carbon/carbonless copy
- MAY contain pre-numbered pages (not required)
- A blue or black ink pen
- A calculator
- Lab safety glasses or goggles
- Regular access to computer with Microsoft Word and Excel (software is free for UNT students)
Lab safe attire is required for every student, every day.
- Shoes that fully enclose the feet
- NO sandals, NO exposed toes, etc.
- Long pants
- Long hair should be pulled back and secured
- NO acrylic nails (they are very flammable)
- PPE should be worn any time any students are conducting experiments in the lab
This is a brief 1-2 page report that only details the results and conclusions of analysis. It does not contain any testing methods or discussion of how conclusions were obtained. It is particularly useful for non-scientists to easily understand results.
This is the full record for a piece of evidence that's usually maintained in a document management system. It may contain calibration curves, sample preparation details, specific analytical methods used, explanation of conclusions, chain of custody, testing requests, analyst documentation, and more.
Requirements for these vary but are generally intended to ensure students conceptually understand the technique and can clearly communicate data, interpretations, and conclusions.
