We followed the procedure described by and . Approximately 50 L DMDS and 5 L iodine solution (60 mg of I2 in 1 mL of diethyl ether) were added to 20 female equivalents in a 1.8-mL glass vial, sealed with a Teflon-lined cap, and held at 40°C for 15 h. The reaction was quenched with 50 L of 5% aqueous sodium thiosulphate, and the organic layer was dried with anhydrous sodium sulphate and transferred to a clean 1.5-mL tapered-bottom vial, and blown down with a stream of argon to approximately 10 L. A 1-L aliquot [ca. two female equivalents (FE)] was immediately analysed by GC/MS.