A Móra Ferenc Múzeum Évkönyve, 1969. 2. (Szeged, 1969)

K. Dávid, Péter: Thermoanalytical Study of Human Bone Remains

A Móra Ferenc Múzeum Évkönyve 1969/2 THERMOANALYTICAL STUDY OF HUMAN BONE REMAINS by PÉTER К. DÁVID (Research Institute for Electrical Industry, BUDAPEST) The thermal decomposition of substance is charasteristic to it's physical and chemical structure. The systematic observation of the thermal decomposition — named thermal analysis — is a sensitive method of analytical chemistry and research on the materials. [1] The material complexity of bones: the simultaneous existence of organic and inorganic components was the reason to extend the field of thermal analysis by the study of bones, [3] Today commercial thermoanalytical instruments are already available with easy handling and especially the derivatograph is remarkable [2] since it measures the following data in the very same sample, simultaneously. Fig. 1 shows the derivatogramm of a 0,300 gramm sample of powdered bone from the year of 1931. The heating rate was 10 C°/min. The derivatogramm consists three curves, all belonging to the same temperature axis: as a function of temperature. The lower one (TG) represents the weight-loss of the sample, the intermediate one (DTG) shows the rate of the weight-loss, the upper one (DTA) characterises the heat formation in, or absorbed by the sample; this manner, by the DTA curve it is possible to indicate thermal effects without weight change (for example: melting, depolimerising, etc.) The derivatograph — as is evident from Fig. 1. — is suitable for simultaneous recording of variations in enthalpy and weight of the substance caused by thermal effects, in the function of the sample's temperature. An advantage of the instrument is that these variations can be measured in the same sample, and beside that also the rate of weight variations is recorded (DTG curve) by the automatic derivation of the weight (TG) curve obtained in the course of the measurement. With the aid of the derivative thermogravimetric (DTG) curve, processes 'going on in the sample and often partly overlapping each other can be observed separately, because the frequently very slight inflexions of the TG curve appear as peaks on the DTG curve. Consequently, the results can be evaluted more easily, and moreover, their evaluation is possible sometimes only in this manner. It can be seen from Fig. 1. — especially by the DTG curve that the thermal decomposition of the bone, below 600 C'° consists three well separated processes that is: the decomposition has a stepwise character. On the basis of other thermal studies and only between the limits of the present discussion, we may assume, that in the above mentioned, below 600 C° in three processes forthgoing thermal decomposition also involves the decomposition of the organic components of the bone. 14* 211