Wang Xiangyun, Qi Peipei, Yang Guiling, Wang Xinquan, Zhang Hu, Xu Hao, Wang Zhiwei, Wang Qiang
State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Quality and Standard on Agricultural Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, People's Republic of China; Agricultural Ministry Key Laboratory for Pesticide Residue Detection, Institute of Quality and Standard on Agricultural Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, People's Republic of China; Zhejiang Province Key Laboratory of Detection and Control for Pesticide Residues, Institute of Quality and Standard on Agricultural Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, People's Republic of China.
Chirality. 2014 Aug;26(8):400-4. doi: 10.1002/chir.22339. Epub 2014 May 28.
In this study we investigated the enantioselective degradation of (2RS,3RS)-paclobutrazol in peach and mandarin fruits under field conditions after foliar treatment at 500 mg active ingredient/L using a Lux Cellulose-1 chiral column on a reverse-phase liquid chromatography-tandem mass spectrometry system. Degradations of paclobutrazol in both fruits followed first-order kinetics, with half-lives of about 9 days. Initial deposits were 1.63 mg/kg on peach and 1.99 mg/kg on mandarin; terminal concentrations were lower than 0.05 mg/kg, which was acceptable in most cases. As anticipated, paclobutrazol levels in peels of mature mandarin were about 6.3 times higher than in pulp, indicating the potential risk of peel consumption. We also observed that paclobutrazol degradation in mature mandarin was relatively slow, indicating it might not be efficient enough to hold mandarin fruits on trees for lowering paclobutrazol concentrations. Significant enantioselectivity was observed: the (2R,3R)-enantiomer was preferentially degraded in mandarin (whole fruit, peels, and pulp) but enriched in peach. Because of its more rapid degradation in mandarin and the lower levels observed in pulp compared with peels, potential endocrine-related side effects due to the (2R,3R)-enantiomer pose less of a risk in mandarin than in peach.
在本研究中，我们使用反相液相色谱 - 串联质谱系统上的Lux Cellulose - 1手性柱，研究了在田间条件下，以500毫克活性成分/升进行叶面处理后，（2RS,3RS）-多效唑在桃和柑橘果实中的对映体选择性降解。多效唑在两种果实中的降解均遵循一级动力学，半衰期约为9天。初始沉积量在桃上为1.63毫克/千克，在柑橘上为1.99毫克/千克；最终浓度低于0.05毫克/千克，在大多数情况下这是可接受的。正如预期的那样，成熟柑橘果皮中的多效唑含量比果肉高约6.3倍，这表明食用果皮存在潜在风险。我们还观察到，成熟柑橘中多效唑的降解相对较慢，这表明用它来抑制柑橘挂果以降低多效唑浓度可能不够有效。观察到了显著的对映体选择性：（2R,3R）-对映体在柑橘（整个果实、果皮和果肉）中优先降解，但在桃中富集。由于其在柑橘中降解更快，且果肉中观察到的含量低于果皮，与桃相比，（2R,3R）-对映体引起的潜在内分泌相关副作用在柑橘中的风险较小。
