Blood samples are important for toxicology tests in crime forensics. However, there are other biological samples that are commonly used for post-mortem toxicology. Research three such biological specimens. Describe how they are collected and their significance.

urine, nails, hair

Explanation:

Hair - Is a special matrix for the retrospective investigation of chronic drug abuse or poisoning in criminal cases and allows to demonstrate with sensitive methods even a single administration in low amount.

Urine - Is a preferred sample as it is easy to procure for forensic findings. Drugs and drug metabolites can be the target chemicals for the findings of the forensic explorations in different modes of deaths.

Nails - Using keratinized samples has several advantages over methodologies employing body fluids. Long term exposures to different drugs result in the accumulation of the same in these structures. Nails have been shown to accumulate drugs following a long duration of drug intake. Finger and toenails can accumulate drugs during long term exposure

Vitreous humor, bile, gastric content

Explanation:

Vitreous humor is the gel-like substance that fills the eye. It is collected using a hypodermic needle. A single eye yields about 2–3 mL of vitreous humor. Vitreous humor is least likely to get contaminated by other body fluids. Also, it is less susceptible to microbial contamination, which makes it important evidence. Vitreous humor is mainly used to detect blood alcohol concentrations. Hence, it is significant in cases of motor accidents, sui/cides, and homicides.

The fluid produced by the liver and stored in the gallbladder is known as bile. For postmortem analysis, it is collected using a hypodermic syringe. Sometimes, to avoid contamination, it is necessary to tie the gallbladder prior to collection. Many drugs and heavy metals accumulate in bile. Hence, bile is important evidence where there is a possibility of metal poisoning or drug poisoning.

Gastric content is valuable in cases of poisoning. It is used for initial screening because undigested substances may appear in the gastric content. Sometimes, the odor of the gastric content can provide a clue about what may be present in the sample, for example, pesticide or cyanide.