Applications in Clinical Chemistry

The basic aim of PEC applications in clinical chemistry, apart from the recovery of standards of endogenous substances, consists of structural identification of isolated (without further separation) substances of relatively high purity. Therefore, the majority of works devoted to this topic pertain to semipreparative separation. Obtaining low amounts of analytes, achieved by coupling TEC with modem... 

Many pesticides are neurotoxicants poisoning the nervous system. A number of pesticides are acetyl cholinesterase inhibitors (Serat and Mengle 1973). Generally, pesticides determination has been performed by GC since the 1960 s (Morrison and Durham 1971 Fournier et al. 1978). There are no reference materials for pesticides in urine or serum, although as with PAHs there are a number biological matrices certified for the content of various pesticides available for environmental food and agriculture analysis and which may have some application in clinical chemistry. 

General books [213-217], chapters [218], and reviews were published in the 1980s reporting the suitability of CL and BL in chemical analysis [219-222], the specific analytical applications of BL [223], the CL detection systems in the gas phase [224], in chromatography [225, 226], the use of different chemiluminescent tags in immunoassay, and applications in clinical chemistry [227-232] as well as the applications of CL reactions in biomedical analysis [233]. 

Development of lithium selective electrodes (LiSE) and their application in clinical chemistry have been amply reviewed Several models of lithium ion specific electrodes are commercially available. The central problems in developing such sensing devices are their dynamic range, the accuracy and precision by which the signals are correlated to the concentration of the analyte and the selectivity towards that species, especially in relation to other alkali metal cations. Additional problems of practical importance are the times of response and recovery and the durability of the electrode in the intended service. 

This review is written for the clinical chemist who wishes to understand the principles of the main classes of instruments, their relative merits and applications, and the types likely to be important in the future. Equipment used for data processing, in vivo analysis, cell counting and morphology is excluded. Some instruments described in standard textbooks [e.g., (S15, W18)] have been omitted either because they have not developed significantly in recent years (e.g., nephelometers, refractometers) or because they have found little application in clinical chemistry (e.g., thermal analyzers). 

Other new sensory membranes are being developed for use with neutral molecules, but despite the time and effort spent on developing specific ion exchange membranes, they have so far found only limited application in clinical chemistry. Liquid ion exchangers are more promising and as well as being extremely versatile are said to be easier to manipulate. Their future role will depend on improvements in their selectivity (R14). 

In general, electrometric methods have found little application in clinical chemistry, but some of these may become more popular in future, particularly in view of their cheapness and the ease of recording the electrical signal. 

HIGH-RESOLUTION ANALYTICAL TECHNIQUES FOR PROTEINS AND PEPTIDES AND THEIR APPLICATIONS IN CLINICAL CHEMISTRY... 

Clark and Kricka have reviewed High-Resolution Analytical Techniques for Proteins and Peptides and Their Applications in Clinical Chemistry and include consideration of isotachophoresis, high-performance liquid chromatography, and high-resolution two-dimensional electrophoretic techniques for separation and analysis of complex protein mixtures. These techniques are not now widely used in clinical chemistry laboratories but represent the tools of the future, when laboratories will be required to measure gene products and the myriad proteins present, as in complex biologic fluids of significance in health and diseases. 

Wu, A.H.W. (2006) A selected history and future of immunoassay development and applications in clinical chemistry. Clinica Chimica Acta, 369, 119 124. 

Sherwood RA and Rocks BF (1989) Applications in clinical chemistry. In Burguera JL, ed. Flow injection atomic spectroscopy (Practical Spectroscopy, Vol 7), pp. 259-291. Marcel Dekker, New York. 

B. Xia and P. Mo, Flow Injection Analysis and Its Application in Clinical Chemistry [in Chinese]. Zhonghua Yixue Jianyan Zazhi, 9 (1986) 117. 

It is beyond the scope of this review to discuss, except in brief outline, the hypothalamic substance, thyrotropin-releasing hormone (TRH), and its application in clinical chemistry, although many publications on TRH have appeared over the last five years or so. However, only a limited number of clinical applications of TRH are related primarily to the thyroid gland. Some reviews which include information on TRH have appeared recently (H7, H14, S8). A review on hypothalamic releasing hormones appears in this volume (H6A). Reference to the physiological role of TRH has been made in Section 2.4. 

The carbohydrates are a problematical group of compounds from the point of view of detection, having neither useable spectrophotometric or fluorescent properties. The method of choice for detection of carbohydrates in pure solution has been refractometry but interference from other compounds in body fluids and its relative insensitivity has limited its application in clinical chemistry. The development of pulsed amperometric detection at noble metal electrodes and improvements in anion-exchange columns has now made possible the separation and quantitation of most carbohydrates of interest in urine samples. As ion-exchange columns require a constant ionic concentration to achieve consistent separations, urines are first desalted with... 

This section deals with the fabrication of potentiometric probes and their use in SECM studies. Potentiometric probes (see Chapter 7) can detect many non-electroactive species not accessible to amperometric techniques. They are highly selective and have found widespread application in clinical chemistry, in environmental studies and the food industry. A general review of potentiometric probe fabrication has been presented previously, and several publications have demonstrated the utility of potentiometric probes in SECM studies (55). This section will provide the reader with a highlight of potentiometric probe fabrication techniques taken from the literature. The section will also include a discussion of the basic concepts, fabrication steps, necessary equipment, and characterization of ion-selective micropipettes applied in SECM studies. 

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