Toxicological analysis analytical techniques

From a toxicological and physiological point of view, the determination of very small amounts of tellurium is becoming increasingly important. Interest is environmental and human health has promoted development in analytical techniques and methods for the trace and ultra trace levels (see Trace AND RESIDUE ANALYSIS). 

GC/MS has been employed by Demeter et al. (1978) to quantitatively detect low-ppb levels of a- and P-endosulfan in human serum, urine, and liver. This technique could not separate a- and P-isomers, and limited sensitivity confined its use to toxicological analysis following exposures to high levels of endosulfan. More recently, Le Bel and Williams (1986) and Williams et al. (1988) employed GC/MS to confirm qualitatively the presence of a-endosulfan in adipose tissue previously analyzed quantitatively by GC/ECD. These studies indicate that GC/MS is not as sensitive as GC/ECD. Mariani et al. (1995) have used GC in conjunction with negative ion chemical ionization mass spectrometry to determine alpha- and beta-endosulfan in plasma and brain samples with limits of detection reported to be 5 ppb in each matrix. Details of commonly used analytical methods for several types of biological media are presented in Table 6-1. 

The consumption of illicit drugs is a growing social and health problem which involves people of different ages and social classes all over the world. This phenomenon has pushed the research in analytical and forensic toxicology toward a fast evolution the development of even more sophisticated analytical techniques with better performances, reduced analysis time, and better knowledge of the biological matrices. 

Directions of Analysis Analytical procedures depends on the type of problem set. Unknown circumstances of an event or an unknown toxic factor require the application of systematic toxicological analysis (STA), so that the analytical procedure encompasses as many toxic substances as possible. In cases where the administered toxic compound is known, first of all a course of analysis targeted at this compound is conducted, and a positive result must be confirmed by another independent method. When working on a case in which only the symptoms of the action of an unknown toxic factor are given, the ability to use complementary techniques as well as knowledge of the fields of medicine, pharmacology and pharmacokinetics are of particular importance [53]. 

Analytical techniques involving enzymes are important in food science and nutrition, in clinical medicine, in toxicology and pesticide analysis, in soil science, in microbiology as well as in biochemistry, chemistry, and physiology. Examples of applications in these areas are given throughout this discussion. 

An important analysis regarding toxicological and legal requirements of flavourings is the control of heavy metal contaminations. Most of the heavy metals show toxic effects in humans, even in trace quantities. Their determination can only be accomplished using trace analysis techniques. In practice, the different analytical techniques Atomic Absorption Spectrometry (AAS) and Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) have been employed successfully. Both methods require complete dissolution of the sample by decomposition. 

Although these analytical methods seem insensitive compared to modern techniques, trace analysis was not required to detect the relatively high levels of perchlorate contained in Chilean caliche. Furthermore, early toxicological reports did not indicate that perchlorate was relevant to human health at milligram per kilogram and higher... 

Trichothecene mycotoxins are secondary metabolites of various fungal species. Structures of some trichothecene mycotoxins of interest to the US ARMY are given in Figure 1. Several methods have been reported for the analysis of these toxins (1-11, 15). Of these, mass spectrometry techniques are both sensitive and definitive when applied to toxicologic and environmental samples. With current technology, the most sensitive and qualitatively definitive analytical technique for the determination of these toxins is derivatization with an electron deficient moiety followed by analysis with negative ion chemical ionization gas chromatography-mass spectrometry (NICI-GC/HS). 

Recent advances in hyphenated analytical techniques, where a separation device is coupled online with detectors generating spectral information, have remarkably widened the analysis field of complex biological matrices. During the last few years covered by this chapter, a number of papers describing the application of TLC, GC-MS, HPLC-UV, HPLC-UV/MS, CE-MS, and NMR to the qualitative and quantitative analysis of tropane alkaloids in toxicological, physiological, forensic, phytochemical, and chemotaxonomical studies have been published. 

High-performance liquid chromatography, or HPLC, is an analytical technique capable of detecting specific components in a sample. In forensic science this test is used for drug analysis, toxicology (study of poisons), explosives analysis, ink analysis, fibres and plastics. 

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