Figure 4.

Smartphone mounted on portable instrument that provides the chip with temperature-regulated heating, optical excitation with a blue LED, a filter to block the excitation light from the smartphone camera and detection. The heating is provided with an exothermic reaction in which a magnesium alloy powder interacts with water. The temperature is regulated with a phase change material (PCM, e.g., paraffin) that acts as a ballast to maintain the reaction chambers at the PCM melting temperature, since excess heat production is absorbed as latent heat, maintaining the reaction chamber at the PCM melting temperature [42].