These dataset files show the calibration of a sensor for mercury (II) ions using a Fluorimeter and either HgCl2 or HgNO3. A range of different sample conditions are tested, including sensor concentrations and relative proportions of water and a methanol co-solvent (required for solubility of the probe). Also tested was the ability of acid to affect the probes sensitivity to mercury as nitric acid is needed for the stability of HgNO3 as an analyte. File names listed show the concentration of sensor and the ratio of water to methanol tested. Inductively coupled plasma mass spectrometry (ICP-MS) data are also given these are used to validate the sensors calibration and also to monitor the levels of soluble mercury content of dental amalgam samples held at either (11⁰C or 37⁰C) in water and saliva. The supernatant of these suspensions is filtered and measured using ICP-MS to give the data as reported. Full details about this nonGeographicDataset can be found at https://doi.org/10.5285/bc82f15b-8db6-4398-bfec-655a1eecf2d7