2.1.4. Solvent-Extracted Pigment Concentration

Standards corresponding to the extracts with DCM have been previously used to determine pigment concentration based on CIE L\*a\*b\* values, not dry weight, when working with pigmenting spalting fungi [17,53,55,58]. The color values were used instead of the dry weight due to the simplicity of a direct extraction from the dry plates with DCM. The standard CIEL\*a\*b values utilized were established by [59] with a range of +/− 2.0 for each fungal species, including: *C. aeruginosa* L\* = 82.28, a\* = − 11.06, b\* = −5.40 and *S. cuboideum* L\* = 82.32, a\* = 26.84, b\* = 13.19. Three milliliters of each of the extracted solutions was added to a VWR glass cuvette for analysis on a Konica Minolta Chroma Meter CR−5 colorimeter, and concentration adjusted through the addition of solvent or evaporation to match these color values. After the read, the dye solution was returned to the vial and stored for future use.
