Department of Entomology, Michigan State University, 243 Natural Science Building, East Lansing, Michigan 48824-1115, USA.
J Agric Food Chem. 2012 Mar 28;60(12):2958-66. doi: 10.1021/jf205169f. Epub 2012 Mar 9.
Infinite- and finite-dose laboratory experiments were used to study the penetrative and dislodgeable residue characteristics of (14)C-insecticides in apple fruit. The differences in dislodgeable and penetrated residues of three radiolabeled insecticides ((14)C-thiamethoxam, (14)C-thiacloprid, and (14)C-indoxacarb), applied in aqueous solution with commercial formulations, were determined after water and methanol wash extractions. The rate of sorption and extent of penetration into the fruit cuticles and hypanthium of two apple cultivars were measured after 1, 6, and 24 h of treatment exposure, using radioactivity quantification methods. For all three compounds, 97% or more of the treatment solutions were found on the fruit surface as some form of non-sorbed residues. For indoxacarb, sorption into the epicuticle was rapid but desorption into the fruit hypanthium was delayed, indicative of a lipophilic penetration pathway. For the neonicotinoids, initial cuticular penetration was slower but with no such delay in desorption into the hypanthium.
采用无限和有限剂量实验室实验研究了（14）C-杀虫剂在苹果果实中的穿透和可洗脱残留特性。通过水和甲醇洗脱提取后，测定了三种放射性标记杀虫剂（（14）C-噻虫嗪、（14）C-噻虫啉和（14）C-茚虫威）在水溶液中以商品制剂施用后的可洗脱和穿透残留的差异。使用放射性定量方法，在处理暴露 1、6 和 24 小时后，测量了两种苹果品种果实表皮和花托中两种杀虫剂的吸附速率和穿透程度。对于所有三种化合物，超过 97%的处理溶液以某种形式的非吸附残留存在于果实表面。对于茚虫威，吸附到外角质层很快，但解吸到果实花托中延迟，表明存在亲脂性渗透途径。对于新烟碱类杀虫剂，初始角质层穿透较慢，但在解吸到花托中没有这种延迟。
