GC-ECD analysis of S-metolachlor (Dual Gold) in cotton plant and soil in trial field.
The analytical method of S-metolachlor residue and its degradation in cotton and soil in trial field were investigated. S-metolachlor EC (96% w/w) was applied as pre-emergence at dosages of 1,500 and 2,250 ml ha(-1) 3 days after sowing of the cottonseeds in the field. The soil and the plant samples were collected at different intervals and the residues of S-metolachlor were analyzed by GC-ECD. The results showed that the degradation of S-metolachlor in cotton leaves in Beijing and Nanjing coincides with C = 0.1113e(-0.1050t) and C = 0.1177e(-0.1580t), respectively; the half-lives were about 6.6 and 4.4 days. The degradation of S-metolachlor in soil in Beijing and Nanjing coincides with C = 1.0621e(-0.0475) (t), and C = 0.9212e(-0.0548) (t), respectively; the half-lives were about 14.6 and 12.6 days,. At harvest time, the S-metolachlor in cotton seeds and soil samples were detected by GC-ECD and confirmed by GC/MS. The results showed that the residues in cottonseeds were lower than the USA EPA's maximum residue limit of 0.1 mg kg(-1) in cottonseed. It could be considered as safe to human beings and environment.
Cao
Pengying
P
Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100094, People's Republic of China.
Liu
Fengmao
F
Wang
Suli
S
Wang
Yuhong
Y
Han
Lijun
L
D000081:Acetamides / Q000032:analysis*; D002849:Chromatography, Gas / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D003368:Gossypium / Q000737:chemistry*; D006540:Herbicides / Q000032:analysis; D015203:Reproducibility of Results; D012987:Soil / Q000032:analysis*
D000081:Acetamides; D006540:Herbicides; D012987:Soil; C051786:metolachlor