In 1928, Paul Job published a paper entitled Formation and Stability of Inorganic Complexes in Solution. He looked into the study of ion associations. Part of his research focused on relating UV absorption to the mole fraction of Tl(NO3) in a Tl(NO3)/NH3 solution. [1] Plotting the absorbance versus mole fraction yielded the first Job Plot, which provided Job with information about equilibrium complexes and thus complexes present in solution.