METHODS OF Mn(II) DETERMINATION11Studies of Mn(II) levels in rat hepatocytes were supported by NIH grants AM-25551 to Dr. V.L. Schramm, Temple University and AM-17517 to Dr. G.H. Reed, University of Pennsylvania. Studies of Mn(II) uptake by Chlamydomonas were supported by Biomedical Research Support Grant S07 RR05417 to Dr. D.E. Ash and NSF grant PCM-8402330 to Dr. J.H. Hoober.