A '''Job plot''', otherwise known as the '''method of continuous variation''' or '''Job's method''', is a method used in [[analytical chemistry]] to determine the [[Stoichiometry|stochiometrystoichiometry]] of a binding event. The method is named after Paul Job and is also used in [[instrumental analysis]] and advanced [[chemical equilibrium]] texts and research articles. Job first published his method in 1928, while studying the associations of ions in solution.<ref>{{Cite journal|last=Job|first=Paul|year=1928|title=Formation and Stability of Inorganic Complexes in Solution|url=|journal=Annali di Chimica Applicata|volume=9|pages=113-203|via=}}</ref> By plotting the [[Ultraviolet–visible spectroscopy|UV absorbance]] of a solution of {{chem2|Tl(NO3)/NH3}} against the [[mole fraction]] of {{chem2|Tl(NO3)}}, he produced a graph which provided information about the equilibrium complexes present in solution.
