Fifteen new hydroxamic acids were explored in conjunction with trioctyimethylammonium cation for the extractive separation of manganese into MIBK from the anions and cations commonly associated with the metal in environmental samples. The most rapid extraction with the maximum selectivity and sensitivity for the atomic absorption spectrometric determination of the metal in the MIBK extract was achieved with N-p-aminophenyl-2-furylacrylohydroxamic acid. The method enabled the determination of manganese at sub-ppb levels and was applied in the analysis of coal, manganese ore, plant tissue, animal tissue and natural waters.