This function shifts the reference frame of an isotopic data object that has a reference associated (currently only delta values.

shift_reference(iso, ref)

# S4 method for ANY,ANY
shift_reference(iso, ref)

# S4 method for Delta,Delta
shift_reference(iso, ref)

## Arguments

iso the isotope object whose reference frame to shift (delta) the isotope object which is relative to the new reference frame (delta)

## Value

a delta value with the shifted reference

## Note

The function requires the reference of the first delta value to the compound measured in the second delta value. This calculations is also implemented with an arithmetic shorthand. All calculatinos are only permissible if the fractionation factors and isotope values have matching attributes.

Other operations: fractionate, mass_balance