ABSTRACT
Surface characterization of new unused PTFE, PFA and PVDF labware has been carried out by light microscopy, scanning electron microscopy, profilometry and atomic force microscopy. It has been found that in spite of higher micro-roughness, PFA exhibits the lowest nano-roughness and hence seems best suited as vessel material for relatively mild pressureless chemical operations for sample preparation of ultrapure substances, as container material for storage of ultrapure liquids, and for transport of such liquids, e.g., from the producer in the chemical to the end user in the microelectronics industry. This suitability refers only to the surface quality of the investigated materials. PTFE-surfaces, due to the sintering process of production, exhibit the most unfavourable surface quality of the investigated fluorinated polymers.
ABSTRACT
Diethyleneglycol was tested for its general cytotoxic effects in three cell culture test systems and in a novel, automated bacterial test system. The first cytotoxic effects were detected in the cell culture test systems at DEG-concentrations of 1 g/1 and 3g/1. The bacterial test system showed a minimal inhibitory concentration of 5 g/1 DEG (20% growth reduction). Morphological observations showed evidence of membrane damage to the cultured cells by DEG. With the bacterial test system one could determine the amount of DEG semiquantitatively in wines to which this material had been added.
