[Method-performance studies of notified analytical method for fenbutatin oxide and cyhexatin]

Method-performance studies were conducted for the notified revised analytical method of fenbutatin oxide (FBTO) and cyhexatin (CHT). FBTO and CHT spiked into rice, soybeans, spinach, orange, tea powder and tea extract at the level of 0.5 microgram/g for FBTO and 0.1 microgram/g for CHT were analyzed in replicate in 6 laboratories. Means recoveries of FBTO were 85.2-96.5% and those of CHT were 83.5-89.2% except from soybeans (46.5%). Repeatability relative standard deviation values of FBTO and CHT in each crop were in the ranges of 2.3-9.4% and 3.2-6.3%, respectively. Reproducibility relative standard deviations were 3.9-12.6% for FBTO and 8.3-12.9% for CHT. Detection limits were 0.015-0.05 microgram/g for FBTO and 0.005-0.02 microgram/g for CHT.