Plant extracts may contain highly polar and/or highly non-polar substances which can interfere with the separation of pure compounds during isolation if they are present in a very high concentration. Commonly known examples of polar substances are carbohydrates, glycosides and amino acids, while non-polar substances include waxes, oils, sterols and chlorophylls (Klejdus et al. 1999). Preliminar...

1. Rh substances are found in amniotic fluid. Not all anti-Rh sera seem to be suitable for the detection of Rh substances in amniotic fluid. Careful selection of Rh antisera, as well as quantitative considerations, determine success or failure of their demonstration. 2. The baby's Rh type and not the mother's determines the occurrence of Rh substances in amniotic fluid. 3. There are Rh secretor...