“…Various papers have been published (Clifford, 1947 ;Schechter, Pogorelskin & Haller, 1947 ;Fairing & Warrington, 1950;Jones & Riddick, 1951, 1952Krzeminski & Landmann, 1963) describing the isolation of minute amounts of pesticides from biological specimens by means that are usually complex and tedious. Extensive cleanup is required, and is accomplished for example by hexane : aceto-nitrile partitioning (Jones & Riddick, 1952;McKinley & Savary, 1962), paper chromatography (Mitchell, 1957;Muller, Ernst & Schock, 1957;MacRae & McKinley, 1961), thin layer chromatography (Walker and Beroza, 1963), silicic acid (Moats, 1962) and florisil column chromatography (Moddes, 1961 ;Moats, 1963).…”