Detection biological-physiologically

Biological-physiological detection The methods involved here take account of the biological activity of the separated components independent of their physical or chemical properties [12]. 

Physical detection methods are based on inclusion of substance-specific properties. The most commonly employed are the absorption or emission of electromagnetic radiation, which is detected by suitable detectors (the eye, photomultiplier). The / -radiation of radioactively labelled substances can also be detected directly. These nondestructive detection methods allow subsequent micropreparative manipulation of the substances concerned. They can also be followed by microchemical and/or biological-physiological detection methods. 

Just like the physical and microchemical methods of detection, the indirect, biological-physiological detection procedures are very selective when apphed to thin-layer chromatography. Here it is not chemical functional groups or particular physical properties that are selectively detected but effects on highly sensitive biodetectors . The following detection techniques have been employed ... 

Fig. 54 Fields of application and frequency distribution of biological-physiological detection methods.

In principle it is possible to employ physical, microchemical and biological-physiological methods for detection in TLC (Fig. 2). 

Desoxyadenosine oligonucleotides la 76 Desoxycholic acid la 334 11-Desoxycorticosterone la 221 lb 346 Detection, group-specific la 4,7 -, substance specific la 4,7 Detection of lipqjhilic substances la 43 -, biological-physiologically la4,6,7, 9,109... 

Three types of detection methods for TLC may be distinguished, namely physical, microchemical and biological-physiological. The more common detection methods for polymer additives in TLC are given in Figure 4.8. Detection is an off-line process, thus several detection techniques may be used one after the other. 

The determination of the total platinum content in physiological fluids and tissues, both during clinical treatment or after environmental exposure, requires instrumental techniques of sufficient DLs and selectivities. ICP MS provides the most attractive DLs for platinum in biological samples, for example, 7.50 ng/L in human plasma ultrafiltrate after chemotherapy with cisplatin, carboplatin, and oxaliplatin [119] 0.1 pg/mL in blood, serum, and ultrafiltrate samples after chemotherapy with oxaliplatin and 5-fluorouracyl [120] 26 pg/g in DNA isolated from cancer ovarian cells after different exposure times and concentrations of cisplatin [121] and 0.75 pg in DNA extracts from peripheral blood mononuclear cells and tissues from patients treated with cisplatin [122] and 1.0 pg/L in serum, 0.1 pg/L in ultrafiltrate, and 2 pg/L in urine [123]. The ICP MS technique allowed detection of physiological levels of ft in the tmexposed human body 0.3-1.3 ng/L in blood (DL of 0.3 ng/L) [46] 0.48-7.7 ng/L in urine (DL of 0.24 ng/L) [47] and 0.778 ng/g... 

Fig. 54 Fields of application and frequency distribution of biological-physiological detection methods.----------------------- --------------------------------------------------------------...

Even quantitative determinations can be performed using biological-physiological methods. These are discussed by Jork and Weins [114] using the example of enzymatic in situ detection of pollutants. 

These methods of detection do not exploit chemical or physical properties but the biological-physiological activity of substances. They are mostly employed for the detection and determination of antibiotics, alkaloids, insecticides, fungicides, mycotoxins, cytotoxines, vitamins, hot or bitter substances, and saponines. 

For biological/physiological detection, the separated compounds can be transferred to the biological system. Alternatively, bioautographic analyses, reprint methods, and enzymatic tests may also be applied. 

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