sampling Archives » Analytical Toxicology

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Drugs Toxicological Analysis

Sample handling

Sample handling is an important consideration during the pre-analytical phase. Unlike a clinical setting, where the time between sample collection and testing is often very short, significant delays are common in a forensic setting. The pre-analytical phase may be considerable, spanning the time of death and/or discovery of a victim, autopsy and collection of specimens,… read more »

Sweat, Amniotic fluid, Breast milk sampling

Sweat Moisture loss via the skin and elimination of insensible (non-visible) sweat take place during normal breathing at a rate of 0.3–0.7L/day. Sensible sweat refers to perspiration that is actively excreted during stress, exercise or extreme temperature, at rates of 2–4L/h. About half the total volume of sweat is eliminated from the trunk of the… read more »

Saliva sampling

Saliva or oral fluid can be collected non-invasively by expectoration, by aspiration, by vacuum or by saturation of an absorbent swab (Kidwell et al. 1998). Detection times are comparable to those in blood. As much as 1.5L of saliva per day is produced by the submandibular, parotid and sublingual glands inside the mouth. Secretions from… read more »

Entomological specimens

The potential use of insects for detecting drugs and other toxins in decomposing tissues has been demonstrated and reviewed (Introna et al. 2001). If insects or larvae are collected from human remains they should be frozen as soon as possible. Larvae rapidly eliminate drugs when removed from the food source. Drugs, metals and pesticides have… read more »

Tissues sampling

When tissues are sampled they should be collected quickly and placed immediately into airtight containers. This is particularly important if volatiles or inhalants are suspected. Liver, kidney, brain, lung and spleen are the most frequently collected postmortem tissues. Liver Liver is a particularly important organ because of the very large number of drugs that undergo… read more »

Cerebrospinal fluid sampling

Cerebrospinal fluid (CSF) can be collected either by lumbar puncture at the base of the spine using a hypodermic syringe or by withdrawal of cisternal fluid by puncturing the base of the neck. Although there are limited published reference data for quantitative drug concentrations in CSF, this clear fluid comprising mostly water is amenable to… read more »

Injection sites sampling

Excision of skin and tissue (muscle) may be necessary in postmortem investigation of a suspected injection site. Typically a cube of muscle and skin is removed for this purpose. However, it is important to compare the drug concentrations in the suspected injection site with those in a control specimen from the same individual where there… read more »

Urine sampling

In antemortem settings, a mid-stream urine sample is usually collected into a plastic container containing sodium fluoride as preservative. In some settings it may be necessary to take precautions against specimen adulteration. In postmortem settings, urine is collected by insertion using a hypodermic syringe directly into the bladder under visualisation. Puncture of the abdominal wall… read more »

Gastric contents sampling

Gastric content is a potentially valuable specimen for analysis in postmortem and clinical cases. Unabsorbed drug or tablet fragments in the gastric contents may provide valuable information concerning ingested compounds and provide an excellent material for preliminary screening owing to the potentially large amounts of drug that may be present. The absence of a drug… read more »

Bile sampling

Bile is generally aspirated from the gallbladder using a hypodermic syringe. It may be necessary to tie off the gallbladder prior to collection if contamination appears to be an issue. Bile should be collected prior to the liver specimen to avoid contamination. Many drugs of forensic interest accumulate in the bile, particularly those that are… read more »