NORMAL-PHASE LIQUID-CHROMATOGRAPHY OF PLANT HORMONES USING REVERSED CHOLIC-ACID MICELLES AS THE MOBILE-PHASE

When several plant hormones with similar structures are present in a s ample, conventional analytical methods are not sufficiently selective to effectively differentiate them. However, the excellent selectiviy o f micellar liquid chromatography allows similarly structured compounds to be easily differentiated, We used reversed cholic acid micelles di ssolved in tetrahydrofuran as the mobile phase in normal-phase chromat ography of seven plant hormones. Our results conformed closely to thos e predicted by the pseudophase micellar liquid chromatography theory. The chromatographic efficiencies were calculated from the peak width a nd the retention times, and we compared these values with those obtain ed by reversed-phase chromatography using sodium dodecyl sulfate mobil e phase in water. To test the efficiency of this selective method for the analysis of plant tissues that may also contain contaminants, we a pplied it to homogeneous suspensions of spiked maize roots. Recoveries ranged from 91 to 110%, the relative standard deviations were between 0.46 and 10.03%, and the detection limits were between 0.08 and 0.80 mu g g(-1).