Abstract
In this paper, the authors break down the elements of what it means to be an analytical chemist to expose the underlying knowledge structures that contribute to this specialist contextual expertise. An appreciation of the structure of knowledge provides the first step in designing ways to scaffold student development of expertise. We have identified two critical gaps that need to be bridged for students to achieve this: the gaps between complementary networked knowledge structures that can impede high level understanding (the gap between intrinsic and shared fundamentals of Analytical Chemistry), and the gap between networks of understanding and chains of practice that can impede professional practice (the theory-practice gap). We hypothesize the l i n k between these two gaps and the ways in which they may be exploited within the curriculum to promote the development of expertise-where these gaps are no longer problematic. The role of threshold concepts in forming bridges across these gaps is explored here. This represents a key point in the pedagogical content knowledge of teachers of Analytical Chemistry.