Infra–red (IR) spectroscopy is the study of the scattering, reflection, absorption or transmission of IR radiation in the spectral range 800 nm to 1 000 000 nm (0.8 to 1000 μm). In older literature (pre–1970), IR radiation was referred to in terms of wavelengths as microns (μm). Nowadays, the wavenumber (ν̃) unit is used almost exclusively. The relationship between wavenumber [&hellip...
Analytical absorption spectroscopy in the ultraviolet (UV) and visible regions of the electromagnetic spectrum has been widely used in pharmaceutical and biomedical analysis for quantitative purposes and, with certain limitations, for the characterisation of drugs, impurities, metabolites and related substances. By contrast, luminescence methods, and fluorescence spectroscopy in particular, have b...
Immunoassays have a firm place among routine methods for the analysis of drugs in biological fluids and other matrices. The technique may be used by the smallest or largest of laboratories with methods that range from single–use point–of–care tests for the analysis of a single sample to fully automated systems capable of analysing thousands of […]
For some substances, the colour reaction with a particular chemical reagent may be quite specific, but it is much more common for the colour to be produced by a class of compounds. Moreover, compounds that do not fall into the class may also give colours. For some of the tests, the colour reactions can be […]
Amalic acid test (test for xanthines) Method Add to the sample a few drops of 10 M hydrochloric acid followed by a few crystals of potassium chlorate, and evaporate the mixture to dryness. Observe the colour of the residue then add two or three drops of 2 M ammonium hydroxide and again observe the colour. Indications A […]
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, […]
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 […]
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 […]
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 […]
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 […]