On the Relative Stability of Tetraoxo-bisanthrenes related to the Radical Anions of Hypericin 

169

Gutman, I.Markovic, Z.Engelbrecht, J.P.

Abstract

Extraction of Coal-tar Pitch by Supercritical Carbon Dioxide. Dependence of Chemical Composition of the Extracts on Temperature, Pressure and Extraction Time 

179

Markovic, Z.Markovic, S.Engelbrecht, J.P.Visser, F.D.

Abstract

Determination of Total Iron as Fe(II) in Multivitamins, Haematinics and Natural Waters using a Sequential Injection (SIA) System 

191

Van Staden, J.F.Naidoo, E.B.

Abstract

Reporting Low-level Analytical Data 

206

Horwitz, W.

Abstract

Application of Artificial Neural Networks for Analysis of Highly Overlapped and Disturbed Differential Pulse Polarographic Peaks in the Region of Hydrogen Evolution 

213

Cukrowska, E.Cukrowski, I.Havel, J.

Abstract