A solid sample material should always be sufficiently prepared by size reduction and homogenization before it is subjected to chemical or physical analysis. Care should be taken that the analysis sample fully represents the original material and that the sample preparation process is carried out reproducibly. Only then are meaningful results guaranteed. Most sample materials can be reduced to the required analytical fineness at room temperature by choosing a mill with a suitable size reduction principle (impact, pressure, friction, shearing, cutting).
However, there are limits for size reduction at room temperature, for example when even a small temperature increase affects the sample in a negative way; or when the material is very elastic and the above mentioned size reduction principles only cause deformation. The perfect solution for these types of samples is cold or cryogenic
grinding. This involves grinding aids such as liquid nitrogen (-196 °C) or dry ice (-78 °C) which embrittle the sample by cooling and make it break more easily. Another advantage is the preservation of volatile components of the sample.
In this white paper we explain for which sample materials cryogenic grinding is applicable, which laboratory mills are suitable and which other aspects need to be
taken into consideration.