Separation of rotenoids and the determination of rotenone in pesticide formulations by high-performance liquid chromatography.

: The rotenoids deguelin, B-dihydrorotenone, dehydrorotenone, rotenone, 6alpha beta, 12alpha beta-rotenolone, and tephrosin were chromatographed on 8-12 mum silica. A mobile phase of chloroform-isooctane (35+65) pumped at a flow rate of 1 ml/min through a 30 cm column was used and the absorbance of the eluate was monitored at 294 nm. Rotenone, B-dihydrorotenone, deguelin, and dehydrorotenone are completely resolved while 6alpha beta, 12alpha beta-rotenolone and tephrosin chromatograph as one peak. This method has potential as a preparative separation technique for rotenoids. Also described is a procedure to quantitatively measure rotenone in pesticide formulations. Samples were extracted with chloroform and chromatographed at a flow of 2.5 ml/min. The method is rapid (rotenone is eluted in 12 min) and reproducible.