Ultravioletvisible Spectrophotometry

Ultraviolet-visible (UV-Vis) spectrophotometry was one of the earliest instrumental techniques used in postmortem forensic toxicology.26-29 The use of ultraviolet and visible spectrophotometry as a screening tool is based on the fact that many drugs contain aromatic nuclei that absorb light in the UV and visible regions. Such drugs have absorption spectra with maxima and minima at characteristic wavelengths. Furthermore, the spectrum often changes with the ionization state of the drug in acidic...

Info

Richard, L., Leducq, B., Baty, C., and Jambou, J., Plasma determination of 7 common drugs by high performance liquid chromatography , Annales de Biologie Clinique, 47, 79-84, 1989. Schmutz, A. and Thormann, W., Determination of phenobarbital, ethosuximide, and primidone in human serum by micellar electrokinetic capillary chromatography with direct sample injection, Therapeutic Drug Monitoring, 15, 310-316, 1993. Miles, M. V., Howlett, C. M., Tennison, M. B., Greenwood, R. S., and Cross, R. E.,...

Other Considerations

Severe trauma can affect the interpretation of both alcohol and drug concentrations. For example, it is not uncommon for severe motor vehicle accidents to result in rupture of the stomach and diaphragm. This can easily result in the release of gastric fluid into the body cavity. Because blood may be difficult to obtain from discrete vessels, pooled blood from the pleural cavity may be sampled. If an autopsy is performed, the origin and nature of the fluid so drawn should be obvious, and...

S7 Chromatography

Chromatographic drug screening techniques separate components of mixtures by partitioning them between a stationary phase, usually a solid or viscous liquid, and a mobile phase consisting of a gas or liquid. Under a given set of chromatographic conditions, the time required for a substance to traverse the chromatographic column (retention time) or the distance traveled on a TLC plate relative to the solvent front (Rj) is a constant. Separated analytes are detected and identified by a variety of...

References

Joint Committee of the American Academy of Forensic Sciences (AAFS) and the Society of Forensic Toxicologists, Inc. (SOFT), Forensic Toxicology Laboratory Guidelines, Colorado Springs, 2002. Available online from www.soft-tox.org. 2. Ayres, G.H., The analytical balance and its use, in Quantitative Chemical Analysis, 2nd ed., Harper & Row, New York, 1968, chap. 2. 3. Schenk, G.H., Hahn, R.B., and Hartkopf, A.V., Fundamentals of weighing and related measurements, in Quantitative Analytical...

And Metaloids

Toxicologists should be prepared to support investigations that involve toxic exposure to metals and metaloids. Proper sample collection and rigorous state-of-the-art analytical techniques are critical to prevent exogenous contamination.353 354 A number of different techniques may be employed for the identification of such compounds flame atomic absorption spectroscopy (FAAS),355 graphite furnace atomic absorption spectroscopy (GF-AAS),356,357 inductively coupled plasma-emission spectroscopy...

Postmortem Redistribution And Other Changes

One question should be asked before attempting to interpret postmortem drug concentrations Is the concentration found likely to represent, at least approximately, that present at the time of death Unfortunately, the answer is often a flat no, or at least not necessarily. A number of factors need to be considered. It is often the case that sudden deaths involving drugs are caused by abuse or suicidal drug overdose. Death will therefore usually occur before steady state has been reached. If a...

What Drug Give Negative And Positive Result With Trinder Test

Immunoassays imply the use of urine however, if a urine specimen is unavailable, or indicates the presence of a drug, a blood analysis should follow. At a minimum, perform amphetamines, barbiturates, benzodiazepines, cocaine, opiates, PCP, and others as required by case type and history. CO (carbon monoxide) Between the months of September and May, request on all MEO (medical examiner office) cases involving apparent natural death and pending cases occurring indoors. MCTs Require urine and...

Pharmacokinetics

In this section we review the basics of pharmacokinetics as it relates to postmortem interpretation. The kinetics of all drugs and poisons in the body are characterized by absorption, distribution, metabolism, and excretion. All these parameters affect the concentrations that will be found in the body after death, and therefore interpretation of analytical toxicology results. Absorption may be via the oral route, parenteral (e.g., intravenous, intramuscular, subcutaneous), pulmonary, dermal,...

Simple Chemical Tests

Chemical tests were once the mainstay of postmortem toxicology.21,124-127 Today, many have been abandoned and replaced by automated broad range screening procedures. However, some are still useful as supplemental tests to rapidly and easily detect drugs and poisons that are not detected by the other screening tests. Virtually all clinical and forensic toxicology laboratories utilize micro-color tests to indicate the possible presence of drugs or toxins the so-called spot tests.21,125,127-133...

Trifluoperazine Toxicology

Gastric contents, 35, 118 nonbiological evidence, 25-26 Talbutal, 146 Tandem liquid chromatography-mass spectrometry (LC- MS-MS), 32, 81 Tandem liquid chromatography-mass spectrometry time of flight (LC-MS-MS-TOF), 71 Tellurium, 35 Temazepam, 146 Terbutaline, 146 Terfenadine, 146 Terminal illness, 6-7 Test dip-sticks, 35 Tetracaine, 146 Tetrahydrocannabinol (THC), 39, 41 Tetrazepam, 146 Theophylline, 82, 146 Therapeutic drug analysis and monitoring ethchlorvynol test, 34 fundamentals, 8 hair...

P

Blood drug level interpretation, 115 extraction adjustment, 48 gastric contents, 35 liquid chromatography, 74 liquid-liquid extraction, 47 preservatives, 15 test dip-sticks, 35 vitreous humor, 116 Pharmacogenetics, 122 Pharmacokinetics, 121-123 Pharmacological classifications, 147 Phencyclidine (PCP) confirmation, 78 investigation strategies, 71 pH adjustment, extraction, 48 quantitative analysis references, 145 screening immunoassays, 39 Phendimetrazine, 145 Phenelazine, 145 Phenobarbital fly...

Sample Calculations

Logan, Ph.D.1 and Alan Wayne Jones, D.Sc.2 1 Director, Washington State Toxicology Laboratory, Department of Laboratory Medicine, University of Washington, Seattle, Washington 2 Department of Forensic Toxicology, University Hospital, Link ping, Sweden This section presents some typical scenarios based on authentic DUI cases. Bear in mind that statutory per se alcohol limits are somewhat arbitrary, and that a person's driving might be influenced below the so-called legal limit. For this...

Analytical Chemistry In Postmortem Toxicology

Analytical toxicology is an applied science.1-4 Toxicologists must be familiar not only with the effects and toxic mechanisms involved in poisoning, but also with the metabolism of drugs, the chemical properties of parent drugs and their metabolites, and the composition of biological samples. The detection and measurement of toxicologically relevant concentrations of potent new drugs require the use of analytical techniques on the forefront of instrumental technology.5-9 Immunoassay technology,...

Selection Of Postmortem Specimens

The choice of specimens available in a postmortem forensic toxicology investigation can be numerous and variable. Specimens may be selected based on case history, institutional policy, and availability for a given case. Generally, the specimens routinely collected from cases in which an autopsy was performed include blood from both peripheral and cardiac sources, all urine and bile available, vitreous humor, all available gastric contents, and tissues (particularly liver).2 However, because the...

The Toxicology Examination

The toxicologic investigation typically begins with the preliminary identification of drugs or chemicals present in postmortem specimens.30-39 Confirmatory testing is then performed to conclusively identify the substance(s) present in the postmortem specimens. In a forensic laboratory, positive identification must be established by at least two independent analyses, each based on a different analytic principle. The next step in the process is to determine the quantity of substance in the...

Quantification Of Drugs And Poisons

When you can measure what you are speaking about and express it in numbers, you know something about it but when you cannot express it in numbers, your knowledge is of meagre and unsatisfactory kind. Screening and confirmation qualitative tests establish the presence of a specific substance quantitative tests measure the amount of that substance in a particular specimen. Qualitative information alone can demonstrate that the deceased was exposed to the substance before death, and may even...

The Review Process

Individual cases should be reviewed periodically to assess the status of the investigation and the quality of the acquired data. Reassessment may suggest the need for additional tests. Before a report is issued, the entire case file must be reviewed to ensure that results are forensically acceptable and that sufficient data have been gathered to determine whether, and to what extent, drugs or poisons influenced the cause and manner of death. When testing has been completed, the toxicologist...

Immunoassays

Immunoassays for postmortem toxicology are sold commercially as kits. Often, they are exactly the same products as those used for urine drug screening in forensic urine drug testing programs.142 Such products are standardized and validated by the manufacturer, and are approved by the U.S. Food and Drug Administration FDA . They are intended and approved for the analysis of particular specimen types, such as urine or serum. When urine cannot be obtained, other tissue may be used. A number of...