Figure 3.

Workflow for a typical iron limitation experiment using Aquil. The workflow is split into two distinctive parts. Preparation of sterile and trace-metal free Aquil includes the preparation of several stock solutions for, e.g., copper and selenium as individual metal stocks, before sterilization and subsequent addition to a final medium. Daily sampling of biological parameters such as the OD₇₃₀, pH, and 77K Fluorescence emission analysis (indicated as 77K FEA) are strongly recommended. Inductively coupled plasma mass spectrometry (indicated as HR-ICP-MS) and Flow Injection Analysis (indicated as FIA-CL) should be sampled according to a carefully considered sampling scheme, taking into consideration the length of the experiment as well as the density and health of the culture. An example of a full sampling procedure including all protocols can be found in the Supplementary Materials.