Thermally stimulated luminescence of urine salts

Abstract

We investigated thermally stimulated luminescence (TSL) of urine salts in the normal state and with oxalate, urate, and phosphate salts. We found that the presence of pathological salts leads to a decrease of TSL intensity and to the appearance of additional TLS bands with maxima at 118 and 205 K in addition to the characteristic bands at 173 and 260 K. The TLS bands are related to the urine components. The TSL intensities of urine salts of different chemical composition are compared. The thermal activation energy of the strongest TSL bands is determined.Introduction. Investigations of water-salt exchange by body fluids are important in modern research on the physiology of living organisms and deviations from normal functioning of organs. The problem of water-salt exchange is important theoretically and for therapy of kidney and other diseases arising as a result of disruptions of this type of exchange processes in the organism.Kidneys are the main organs that provide constant physical chemical characteristics for a living organism. The product of their activity, urine, can provide diagnostic information about the organism. Disruptions of exchange lead to the appearance in urine of salts that it does not normally contain. These salts can be indicative of various diseases. Salts that correspond to the development of kidney stones, for example, oxalates [Me 2 (COO) 2 ], urates [MeC 5 H 3 O 3 N 4 ], phosphates [Me 3 PO 4 ], and others are especially significant. Investigation of the luminescent properties of these salts is rather critical for advancing medical diagnostics. This method together with known biochemical methods can be applied to rapid diagnosis without using chemical preparations [1][2][3][4][5].Experimental. Urine samples obtained from the clinical laboratory of Lvov Regional Specialized Clinical Hospital were investigated. Samples were analyzed biochemically beforehand. We used urine (2-3 drops) placed on a quartz plate and heated to 40-50 o C. Dry solids after evaporation of the liquid were investigated. All samples were prepared under identical conditions. Samples for TSL studies were placed in a vacuum cryostat where the temperature was varied in the range 80-400 K. Radiation from a URS-55 x-ray generator (40 kV, 10 mA, Russia) with a copper anode at 80 K was used. The exposure (D) was measured with an IDMD-1 dosimeter. The total TSL emission intensity was recorded with a FÉU-551 photomultiplier (Russia) with an electrical amplifier, the output signal of which was fed to a PDA-1 potentiometer (Ukraine).Results and Discussion. Figure 1a-d shows TSL curves (total luminescence intensity as a function of temperature) for normal urine salts and those with pathological salts. It can be seen that two characteristic TSL bands with maxima at 173 and 260 K are identified in the studied temperature range regardless of the presence of pathological salts. The band with a maximum at 173 K dominates all samples. Furthermore, the presence of pathological salts leads to the appearance of two additional TSL bands wi...