| In this paper, residual levels and degradation rates of the acaricide Peropal, tri(cyclohexyl)-(l,2,4-triazol-lyl) tin, in apples have been studied. 250—500 ppm solutions of tested acaricide were sprayed to the test trees at Beijing and Dalian orchards for 1—4 times. After 14 days of the last spray, residues in the apples were at 0.05—0.16 ppm. The half-life was about 14 days in the apples, about 20 days in soil under the fruit trees respectively.Wethod for gas-chromatographic determination of Peropal and its major degradated product (tricyclohexy-hydroxytin) has been established. The procedures are: first to convert the residues into their bromides, then to follow reaction with Grignard reagents quantitatively, last to determine the yielded tricyclohexyl-methyltin with GC-FPD. |
