MIBK is employed to extract the complex from aqueous solution,which separates Fe~(2+) from Fe~(3+) and reduces speciation transformation between the two oxidation states.

6 meanwhile Cr3+was hardly extracted when chromium in waste water was extracted by the mixing solvent extrations of MIBK and TBP on condition that PH was less than 1.

The ammonium pyrrolidinyldithiocarboxylate (APDC) was used as a chelate reagent, and then the Pb2+-APDC complex was extracted by methyl isobutyl ketone from an aqueous phase to an organic phase.

Iodine equi-volume extracted with methyl isobutyl ketone from aqueous solution,and then 20~40 μL of an organic solution containing iodine was injected into a pipette using a microsyringe,and the combine electrode was set just on the surface of the aqueous solution.

Slaking the sample of human hair by nitric acid and perchloric acid, then extracting trace cadmium from it by potassium iodide and methyl isobutyl ketone, then spraying the organic phase and mensurating the content of cadmium, and making a comparision between direct method standard addition method and atomic absorption spectrophotometry, the result showed that c.