Malcolm Dole (March 4, 1903 – November 29, 1990) was an American chemist known for the Dole Effect in which he proved that the atomic weight of oxygen in air is greater than that of oxygen in water and for his work on electrospray ionization, polymer chemistry, and electrochemistry.
The Dole effect is the inequality in the ratio of heavy oxygen isotope <sup>18</sup>O to the more abundant <sup>16</sup>O in the Earth's atmosphere and in seawater. This effect was reported by Dole in 1935. The effect is due to slightly different reaction rates for the two isotopes in respiration in plants and in animals which tends to retain the lighter <sup>16</sup>O, which increases the relative concentration of <sup>18</sup>O in the atmosphere. The effect has also been linked to hydrologic processes, such as the enrichment of the lighter <sup>16</sup>O as water vapor is transported poleward.
Electrospray is a process in which a high voltage is applied to a liquid to create an aerosol containing highly charged droplets. Dole in 1968 was the first to use electrospray ionization with mass spectrometry.