Investigations get real

Analytical chemistry is an integral part of the 2008 chemistry specifications at GCSE and A-level, and, at a basic level of paper chromatography, has been part of Key Stage 3 science for years.¹ The new specifications reflect the increasing importance of analytical techniques to chemists and fit in well with 'how science works'. 

At GCSE chromatography and retention factors (R_f) have been written into the specifications with a focus on additives in foods, and at A2 some specifications now expect students to interpret retention times and mass spectral data from HPLC-MS to resolve complex mixtures and elucidate the component structures. 

This presents chemistry teachers with the difficult task of finding suitable course material that can be taught to students from Key Stages 3-5 which explores the requisite parts of analytical science but which also encourages an investigative approach ² that will satisfy the requirements of 'how science works'. The investigation described here exploits chlorophyll chemistry and is my way of addressing these issues. Entitled Which is fresher, supermarket-packed spinach or frozen spinach?,  the investigation can be used at Key Stages 3 and 4, and with modification at Key Stage 5.