RESUMO
226Ra concentrations in human teeth from several cities, mainly Tokyo, Japan, were determined with emphasis on the measurement of low-level 226Ra by alpha-ray spectrometry following chemical separation. No appreciable differences in 226Ra concentration were found among various permanent teeth samples of different age groups in Tokyo. The mean 226Ra concentration for Tokyo was 0.51 +/- 0.06 mBq (g Ca)-1. 226Ra concentration [mean: 0.67 +/- 0.11 mBq (g Ca)-1] in teeth in western regions of the country was statistically higher than that [mean: 0.48 +/- 0.09 mBq (g Ca)-1] in eastern ones. The mean 226Ra concentration [0.51 mBq (g Ca)-1] in teeth from Tokyo was less than the concentration [1.11 mBq (g Ca)-1] reported for vertebral bone samples of this city.
Assuntos
Rádio (Elemento)/análise , Dente/química , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Animais , Bário/análise , Osso e Ossos/química , Cálcio/análise , Criança , Esmalte Dentário/química , Dentina/química , Humanos , Japão , Magnésio/análise , Pessoa de Meia-Idade , Dente Molar/química , Tóquio , Extração DentáriaRESUMO
In fluoride analysis, there are two procedures for the determination of fluoride depending on nature of samples. One procedure directly can determine fluoride contents by fluoride ion electrode, dissociating fluoride from the sample with the acid (perchloric acid). The other procedure needs to separate fluoride from biological sample using steam-distillation or micro-diffusion method, and then the determination by means of fluoride ion electrode can be applied. In this study, we applied a modified microdiffusion method by Hinoide (1990) for its availability in different temperatures and reaction time, and then estimated to determine fluoride contents of Shrimp (Sakura-shrimp) as a biological sample by this method. It is also very important to determine fluoride contents of foodstuffs and biological samples with regard to bioavailability of fluoride in vivo. The results were as follows: 1. Using the modified microdiffusion method, the fluoride recovery rate attained more than 95% in the range of 0.1-10 micrograms fluoride from a standard solution under the experimental condition of 60 degrees C and 90 degrees C of reaction temperatures and 60, 90 and 120 minutes of reaction time. 2. For the sample of shrimp, fluoride contents analyzed by means of the modified micro-diffusion and steam-distillation methods showed almost similar values, although the fluoride contents by steam-distillation method revealed relatively lower value. The difference might be derived from a loss of fluoride in ashing the sample before applying the steam-distillation method. The modified microdiffusion method used in this experiment can be utilized routinely and precisely in fluoride analysis for small amounts of biological sample.