A rapid method for developing chlorophyll equations using alternative solvents: DMF (N,N-dimethylformamide)

Acetone although very good as a spectroscopic solvent is often found to be an unsatisfactory extractant of chlorophylls from photosynthetic organisms and hence often seriously underestimates chlorophyll content. Unfortunately, although spectroscopic equations for organisms with chlorophyll a + b are available in some other solvents, suitable equations for organism with different chlorophyll profiles are often not available and are very labour-intensive and need a lot of expertise to obtain. DMF (N,N-dimethylformamide) is a very good extractant of chlorophylls. DMF is more toxic than DMSO (dimethyl sulphoxide) but it offers the same advantages of very low volatility and limited flammability but has a much lower freezing point. We describe a simple method to obtain usable chlorophyll equations in DMF solvent using available Acetone-based formulae as benchmarks. The workings for the development of the equations is shown so the same appoach can be used for other solvents. The relative errors of the equations are all about ± 2% (see Table).