Chemistry Reference
In-Depth Information
21.3.2 Urine
Aside from water, urine contains a wide range of chemicals, for example; inorganic salts, proteins, hormones,
and many other metabolites. The most clinically significant ingredients are urea and creatinine. Thus it could be
attractive to propose that IR spectroscopic analysis is a reagent free approach which can be performed for multi
component analysis. Urea, creatinine and uric acid are possible to be simultaneously determined in urine samples
by IR spectroscopy. The other reported parameters are also pH, phosphate and sulfate concentration. There have
been some efforts for glucose and protein determination which sometimes have been faced with some limitations.
The IR detection limits are very effective in provision of satisfactory results. Of course apart from pre-
concentration, extraction, aand tedious treatments, there are also some reported pre-conditioning techniques
which would improve the capabilities, enabling the analyst to overcome the problems made by detection limit
of IR spectroscopy. One of these new introduced techniques is micro-fluidic sample preconditioning based on
laminar fluid diffusion interface. Observations have confirmed that it should improve the accuracy while extends
the analytes' detection range. Clinical application of IR spectroscopy for urine samples is not limited to
quantitative analysis of urine ingredients. Hyphenated analytical methods such as GC-FTIR for quantitative
analysis of the drug amphetamine and its derivatives, and NMR and IR spectral analysis for distinguishing
between normal renal transplants and rejected allografts are some of examples [60-65].
21.3.3
Other body fluids
Saliva as an easily accessible sample is useful for many diagnostic aims. It consists of water, enzymes, mucus,
electrolytes, and antibacterial biochemicals. A wide range of analytes such as glucose, amylase, total protein,
urea, immunoglobulin A, cortisol, phosphoprotein and phosphate have been precisely determined in saliva by
means of ATR-FTIR spectroscopy. In case of pattern recognition studies, IR spectral analysis of saliva samples
from diabetes affected patients has revealed informative differences in major metabolic components such as
glucose, lipids, proteins, thiocyanate and carboxylate compared to those of healthy people. Saliva analysis also
enables diagnostic investigation of enamel decalcification in orthodontic treatment and prediction of enamel
decalcification risk [66-69]. IR spectroscopy of mucus as another oral body-fluid is helpful for clinical
diagnosis and even environmental monitoring. Amide related signals in mid-IR region in addition with sugar
side-chains could be utilized for clinical supportive decision making [70]. Kidney dysfunction (glomerulonefritis)
has also been monitored via IR spectroscopy of patients' sweat. Tears from left and right eyes of human have
been analyzed by IR spectroscopy to find the probable spectral variation between them [71, 72].
21.4
Diagnosis in tissue samples via IR spectroscopic analysis
The second section of this chapter confirms that IR spectroscopy is a sensitive analytical tool which can be
generally used to study biomolecules. As tissues are the complex form of cells which contain the above
discussed bio-structures, IR spectroscopy is proposed as a useful analytical method for tissue analysis. Of
course, the variety in tissue samples is usually more complex than body fluids and the consistency in tissue
structures is not as strong as bio-fluids. In a bio-fluid all parts of a homogenous sample are in the same
characteristic while in a small tissue sample the biochemical structure is completely changed from one side
to another one. Thus, in IR spectroscopic analysis of a tissue sample, it is absolutely critical to make an initial
judgment about the biological conformation and morphology before proceeding with IR spectroscopy. In
bio-fluids there is a similar distribution of cell chemicals in the liquid media and this makes the analysis
easier but in tissue, the basic unit is the cell and tissue types are categorized according to cell types. The main
tissue types are epithelial, muscular, connective and nerve. Most of the body's organs are compilation of these
