1. L-Malic acid biosensor for field- based evaluation of apple, potato and tomato horticultural produce Authors: Mobeen Arif, Steven Setford, Kerry Burton and Ibtisam Tothill Reviewer: Bax Smith, B.Sc. (Chemistry), B.Eng. (Electrical Engineering), M.Eng. Candidate (Robotics)

2. Today’s Talk Purpose of the Paper – Why L-Malic acid Biosensor? Characteristics of the Sensor – Electrode Composition – Performance – Inhibitors Results from Real Testing

3. Purpose of the Paper Want a quick, simple and cheap way to detect if apples are ripe Current Methods: – LC, GC – Capillary Isotachophoresis – FTIR Spectrometry – Enzymatic assay with Photometric Detection L-Malic Acid amounts decrease as fruit ripens

4. The Sensor

5. Electrodes: Bare Carbon vs Rhodinised Carbon

6. Sensor Performance

7. Inhibition Effects

8. Testing Real Samples

9. Conclusion Linear Range less than Test Kit: – 0.028-0.7mM vs 0.0038-2.5mM Faster than Test Kit: – 6min vs 24min