is restricted due to the sample volume. The large volume press, however, is ideal to
address this challenge due to the size of the sample volume. Our design of cell is not
transparent; hence, we needed to develop a methodology that would be independent
of visual confirmation. By measuring the compression of the cell through the travel
of the piston, and knowing the pressure in the cell, we were able to design glass
inserts of the correct geometry to enable their fracture at a specific pressure point. We
demonstrated that through the addition of the anti-solvent, we were able to recover
the orthorhombic form of paracetamol to ambient pressure [47]. This was the first
demonstration of this type of crystallisation process in a reproducible manner. There
Fig. 6 The schematic and photograph of the piston-cylinder large volume press developed by
Kamenev (University of Edinburgh) that has been used by our group to recover high-pressure
polymorphs to ambient pressure
Crystallography Under High Pressures
157
address this challenge due to the size of the sample volume. Our design of cell is not
transparent; hence, we needed to develop a methodology that would be independent
of visual confirmation. By measuring the compression of the cell through the travel
of the piston, and knowing the pressure in the cell, we were able to design glass
inserts of the correct geometry to enable their fracture at a specific pressure point. We
demonstrated that through the addition of the anti-solvent, we were able to recover
the orthorhombic form of paracetamol to ambient pressure [47]. This was the first
demonstration of this type of crystallisation process in a reproducible manner. There
Fig. 6 The schematic and photograph of the piston-cylinder large volume press developed by
Kamenev (University of Edinburgh) that has been used by our group to recover high-pressure
polymorphs to ambient pressure
Crystallography Under High Pressures
157