Über die bestimmung von mit 35S, 22Na und 28Mg markierten Aufschluss-chemikalien in Kiefern- und Fichtenholz

Abstract

The penetration of wood for the purposes of pulp manufacture has been studied by means of bisulphite solutions, labeled by 22Na and 35Mgor 28Mg and 35S. Frozen sections were taken from the impregnated wood samples. After their wet combustion the sulphur was precipatated as BaSO 4, filtered out and its activity determined in a methane flow counter; the activity of 22Na was measured in a scintillation counter. The following additional measuring method has been developed. After wet combustion of the wood by nitric acid and after destruction of excess acid the gamma pulse rate of 22Na was determined. The sodium was then removed from the solution by means of a cation exchanger and the activity of 35S was determined in a liquid scintillation counter (LSC). When solution labeled by 28Mg and 35S were used; the cation exchange was found to be not needed. After determining the gamma activity of 28Mg the measuring solution was left standing for 10 days (T 1 2 = 21.3 h) and the 35S activity was then determined in a LSC. The depth of penetration and the paths of penetration of the impregnating solution were demonstrated by autoradiography.