Influence of inverse gas chromatography measurement conditions on surface energy parameters of lactose monohydrate.

Surface energy of any powder determined by inverse gas chromatography (IGC) should be independent of the measurement conditions or type of column used. In this study stainless steel and glass columns were filled with lactose powder. Dispersive and polar components of surface free energy were determined at different flow rates of carrier gas using lactose alone or diluted with calcinated diatomite (Chromosorb W). It was found that measurement conditions did not influence the value of the dispersive parameter of surface energy. On the contrary, K(a) and K(d) values were found to be dependent on dilution of lactose with Chromosorb W. The influence of other parameters on the results was found to be much smaller.