Using multi-wavelength collection, the user-defined fluorescence emission at 510 nm, produced from excitation wavelengths 460 nm and 403 nm (exciting the basic and acidic forms of HPTS, respectively), was recorded using two cell holders. The produced data was exported to a spreadsheet program. Due to pre-treatment from the fluorimeter software, the data was provided as ratiometric (I460/I403) values; the data treatment process is simplified and uses a shortened procedure starting from step 3 of the Transformation and normalisation of unprocessed data sub-section under the Data Treatment section.