Pre-harvest Residue Limit Research Articles

Single‐step modified QuEChERS for determination of chlorothalonil in shallot (Allium ascalonicum) using GC‐μECD and confirmation via mass spectrometry

A single extraction method was developed for chlorothalonil in shallot using gas chromatography with an electron capture detector (GC-μECD). Samples were extracted with single-step modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method using ethyl acetate as an extraction solvent. Significant matrix effects were observed, and the calibration curve was constructed from the matrix. The linearity of the analytical response across the studied range of concentrations (0.01-1.00 mg/L) was excellent, obtaining a correlation coefficient (r(2) ) of 0.996. >0.996. Recovery studies were carried out on spiked shallot blank samples, at two concentration levels (0.4 and 2.0 mg/kg) with three replicates performed at each level. Mean recoveries of 97.2-104.9% with RSDs of 1.3-2.7% were obtained. The method is demonstrated to be suitable for the determination of chlorothalonil in shallot. The dissipation rates of chlorothalonil were described using first-order kinetics, and its half-life was 2.8 days. Based on the dissipation pattern of the pesticide residues, the pre-harvest residue limit (PHRL) was also calculated. Residues were confirmed via mass spectrometry.

단감 재배기간 중 살균제 pyrimethanil과 trifloxystrobin의 생산단계 잔류허용기준 설정

본 연구는 단감 재배 중 사용되는 살균제인 pyrimethanil과 trifloxystrobin의 생산단계 잔류허용기준 설정을 통하여 안전한 단감 생산에 기여하고자 수행되었다. 먼저 pyrimethanil과 trifloxystrobin을 살포하고, 살포 후 0, 1, 2, 3, 5, 7, 10, 12, 15, 18일에 단감 시료를 채취하여 각각의 농약을 분석하고 생물학적 반감기를 산출한 다음 생산단계 잔류허용기준(PHRL; Pre-Harvest Residue Limit)을 설정하였다. 단감 중 pyrimethanil과 trifloxystrobin은 Acetonitrile을 이용하여 추출하고 <TEX>$NH_2$</TEX> cartridge와 PSA를 이용하여 정제하여 HPLC/DAD를 이용하여 분석하였다. 두 농약에서 검출한계는 모두 0.01 mg/kg이었다. Pyrimethanil의 회수율은 0.1과 0.5 mg/kg 두 수준에서 각각 <TEX>$81{\pm}1.62%$</TEX>, <TEX>$98{\pm}1.58%$</TEX> 이었으며, trifloxystrobin의 회수율은 0.1과 0.5 mg/kg 두 수준에서 각각 <TEX>$91{\pm}2.94%$</TEX>, <TEX>$98{\pm}1.25%$</TEX>이었다. 단감에서 pyrimethanil의 생물학적 반감기는 기준량 살포 시 15.6일, 배량 살포 시 11.6일이었고, trifloxystrobin의 생물학적 반감기는 기준량 살포 시 10.4일, 배량 살포 시 10.3일이었다. 잔류회귀 감소식을 이용한 생산단계 잔류허용기준은 pyrimethanil과 trifloxystrobin은 각각 수확 10일 전 2.69 mg/kg과 0.83 mg/kg으로 제안하였다. BACKGROUND: This study was carried out to establish pre-harvest residue limit of fungicides pyrimethanil and trifloxystrobin in persimmon, based on dissipation and biological half-lives of two fungicides residue. METHODS AND RESULTS: Both pyrimethanil and trifloxystrobin were extracted with acetonitrile, clean-up with <TEX>$NH_2$</TEX> SPE cartridge and residue were analyzed by HPLC/DAD. Limit of Detection was 0.01 mg/kg. Average recovery were <TEX>$81{\pm}1.62%$</TEX>, <TEX>$98{\pm}1.58%$</TEX> of pyrimethanil, and <TEX>$91{\pm}2.94%$</TEX>, <TEX>$98{\pm}1.25%$</TEX> of trifloxystrobin at fortification levels at 0.1 and 0.5 mg/kg, respectively. CONCLUSION: The biological half-lives of pyrimethanil were 15.6 and 11.6 days at sprayed with recommended and double dosage, respectively. The biological half-lives of trifloxystrobin were 10.4 and 10.3 days at sprayed with recommended and double dosage, respectively. The pre-harvest residue limit of pyrimethanil and trifloxystrobin were recommended as 2.69 and 0.83 mg/kg for 10 days before harvest, respectively.

취나물의 재배기간 중 살충제 Chlorfenapyr와 살균제 Fenarimol의 생산단계 농약잔류허용기준의 설정

BACKGROUND: This study was performed to investigate pre-harvest residue limit (PHRL) in Chwinamul, to estimate biological half-life for residue of each pesticide. Chwinamul was sprayed with pesticides of standard and double application rate. Chlorfenapyr and fenarimol were sprayed once on Chwinamul at 10 days before harvest, and it was sampled 7 times and analysed the residual change of two pesticides. METHODS AND RESULTS: Chwinamul sample was extracted with acetonitrile and partitioned with dichloromethane, and pesticide residues were determined with GCECD. Method quantitation limit (MQL) of chlorfenapyr was 0.10 mg/kg and that of fenarimol was 0.02 mg/kg. Recoveries of chlorfenapyr at two fortification levels of 1.0 and 5.0 mg/kg were 1.70 and , respectively. Recoveries of fenarimol at two fortification levels of 0.2 and 1.0 mg/kg were and , respectively. CONCLUSION(s): The biological half-lives of chlorfenapyr were about 3.5 days at standard application rate, and 3.4 days at double application rate. The biological half-lives of fenarimol were about 6.0 days at standard application rate, and 5.9 days at double application rate. The PHRLs of chlorfenapyr were recommended as 13.02 and 6.25 mg/kg for 10 and 5 days before harvest, respectively. And the PHRLs of fenarimol were recommended as 2.80 and 1.67 mg/kg for 10 and 5 days before harvest, respectively.