Significance and Use 5.1 Pressing cryosections flat onto a conducting substrate has been one of the most challenging problems in SIMS analysis of cryogenically prepared tissue specimens. Frozen cryosections often curl or peel off, or both, from the substrate during freeze-drying. The curling of cryosections results in an uneven sample surface for SIMS analysis. Furthermore, if freeze-dried cryosections are not attached tightly to the substrate, the impact of the primary ion beam may result in further curling and even dislodging of the cryosection from the substrate. These problems render SIMS analysis difficult, frustrating and time consuming. The use of indium as a substrate for pressing cryosections flat has provided a practical approach for analyzing cryogenically prepared tissue specimens (1).4 5.2 The procedure described herein has been successfully used for SIMS imaging of calcium and magnesium transport and localization of anticancer drugs in animal models (2, 3, 4, 5). 5.3 The procedure described here is amenable to soft tissues of both animal and plant origin.Scope 1.1 This practice provides the Secondary Ion Mass Spectrometry (SIMS) analyst with a method for analyzing tissue cryosections in the imaging mode of the instrument. This practice is suitable for frozen-freeze-dried and frozen-hydrated cryosection analysis. 1.2 This practice does not describe methods for optimal freezing of the specimen for immobilizing diffusible chemical species in their native intracellular sites. 1.3 This practice does not describe methods for obtaining cryosections from a frozen specimen. 1.4 This practice is not suitable for any plastic embedded tissues. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
