Toshiko Mayeda was born in Tacoma, Washington.^[1] She grew up in Yokkaichi, Mie, and Osaka.^[1] When the United States entered World War II after the Japanese attack on Pearl Harbor, she and her father Matsusaburo Kuki were sent to the Tule Lake War Relocation Center.^[2][3] Whilst there she met her future husband, Harry Mayeda.^[4] After the war, she graduated with a bachelor's degree in chemistry from the University of Chicago in 1949.^[5]

Mayeda worked initially as a laboratory assistant to Harold Urey at the University of Chicago, where she was hired initially to wash glassware.^[6][7] They used mass spectrometry to measure oxygen isotopes in the shells of marine molluscs which gave information on the prehistoric temperatures of ocean waters and hence paleoclimates.^[8] Urey developed the field of cosmochemistry and with Mayeda studied primitive meteorites, also by using oxygen isotope analysis.^[9] Later, she worked with Cesare Emiliani on isotopic evaluation of the ice age.^[10][11] When Urey retired from the university in 1958, Mayeda was persuaded to remain there by Robert N. Clayton, and collaborate with him on applications of mass spectroscopy.^[12] She was described as an indomitable research assistant.^[13][14]

Mayeda and Clayton's first research paper considered the use of Bromine pentafluoride to extract Isotopes of oxygen from rocks and minerals.^[15] It remains their most cited work.^[8] From the 1970s until the late 1990s Mayeda and Clayton became famous for their use of oxygen isotopes to classify meteorites.^[12] They developed several tests that were used across the field of meteorite and lunar sample analysis.^[16][17][18] They studied variations in the abundances of the stable isotopes of oxygen, oxygen-16, oxygen-17 and oxygen-18,^[19] and deduced differences in the formation temperatures of the meteorites.^[20] They also worked on the mass spectroscopy and chemistry of the Allende meteorite.^[12][21] They published many scientific papers on the "oxygen thermometer" and analysed approximately 300 lunar samples that had been collected during NASAs Apollo Program.^[8][14] In 1992, a new type of meteorite, the Brachinite, was identified.^[22] Clayton and Mayeda studied the Achondrite meteorites and showed that variations in the oxygen-17 isotope ratios within a planet are due to inhomogeneities in the Solar Nebula.^[23] They analysed Shergotty meteorites, proposing that there could have been a water-rich atmosphere on Mars^[24] and studied the Bocaiuva meteorite, finding that the Eagle Station meteorite was formed due to impact heating.^[25]

In 2002 Mayeda was awarded the Society Merit Prize from the Geochemical Society of Japan.^[7] In the same year, an asteroid was named after her.^[7] Mayeda's husband, Harry, died in 2003. Mayeda suffered from cancer and died on February 13, 2004.^[7] In 2008, the book Oxygen in the Solar System was dedicated to Clayton and Mayeda.^[26]

• Glenn J. MacPherson, ed. (2008). Oxygen in the Solar System. ISBN 9780939950805.