Wu H, Wang J, Yang K, Wang X, Fang N, Duan L, Zhang C, Wang X
Institute of Agro-products Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ministry of Agriculture and Rural Affairs Key Laboratory for Pesticide Residue Detection, Hangzhou, Zhejiang 310021, China.
Institute of Crop Science and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, China.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi. 2025 Mar 11;37(2):201-208. doi: 10.16250/j.32.1915.2024164.
To establish a method for determination of pyriclobenzuron (PBU) residues in rice and paddy environments, and to determine the residual amounts and observe the degradation dynamics of PBU.
In July 2022, the paddies of Zhejiang Academy of Agricultural Sciences were selected as experimental fields, and were divided into the blank control group (no pesticide application), the 1-fold-concentration pesticide group (1 kg/667 m), and the 5-fold-concentration pesticide group (5 kg/667 m), with a 100 m area in each group. At the early tillering stage of rice, 20% suspension of PBU sulfate was sprayed once in the 1-fold-concentration and 5-fold-concentration pesticide groups, and rice plants, paddy water and soil samples were collected 2 h, and 1, 2, 3, 5, 7, 11, 14, 21, 28, 35, 49 d and 63 d following spraying PBU, while rice straw, field soil, brown rice and rice husk samples were collected 98 d following spraying. PBU was extracted and purified in samples using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) pretreatment technique, and the PBU contents were determined in samples using ultrahigh performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The solvent standard working solution and matrix standard working solution were prepared. A linear regression equation was fitted between PBU concentration (x-axis) and peak area (y-axis), and the ratio of the slope () of the matrix standard curve to the slope () of the solvent standard curve was calculated to evaluate the matrix effect of PBU in samples. According to the -, the addition levels of PBU were set at 0.005, 0.050, 5.000, 1 000.000 mg/kg in rice plants, 0.005, 0.050, 2.000, 10.000 mg/kg in paddy water, 0.005, 0.050, 2.000 mg/kg in soil, and 0.005, 0.050, 5.000 mg/kg in brown rice and rice husks. The recovery and relative standard deviation (RSD) of PBU addition were calculated to evaluate the effectiveness of UPLC-MS/MS for determination of PBU contents. The first-order kinetic equation of PBU concentration was fitted in samples at different sampling time points to analyze the trends in PBU degradation in rice plants, paddy water, and soil, and the half-life of PBU was calculated in different samples.
There was a good linear relationship between the mass concentration and peak area of PBU at concentrations of 0.000 1 to 0.020 0 mg/kg under solvent and matrix conditions ( = 0.985 8 to 0.999 7, = -0.47 to 1.62, all values < 0.01). The matrix effects of PBU were 70.26%, 65.42% and 65.12% in rice plants, brown rice and rice husks, indicating a matrix-inhibitory effect, and the matrix effect was 87.06% in soils, indicating a weak matrix effect. The recovery of PBU addition was 77.61% to 100.12% in different samples, with RSD of 1.43% to 6.74%, and a limit of quantification (LOQ) of 0.005 mg/kg, and the addition recovery and RSD met the requirements of the Guidelines for Pesticide Residue Testing in Crops (NY/T 788-2018), validating the effectiveness of UPLC-MS/MS assay. Following spraying PBU at a dose of 1 kg/667 m, the half-life of PBU was 6.24 d in rice plants and 3.43 d in paddy water samples, respectively. The final residues of PBU were lower than the LOQ of 0.005 mg/kg in brown rice and rice husk samples 98 d following spraying PBU. Following spraying PBU at a dose of 5 kg/667 m, the half-life of PBU was 15.75 d in rice plants and 7.62 d in paddy water samples, respectively. The final residue of PBU was lower than the LOQ of 0.005 mg/kg in brown rice 98 d following spraying PBU, and the final residue of PBU was 0.049 mg/kg in rice husks.
A simple, and highly accurate and precise UPLC-MS/MS assay has been developed for determination of PBU residues in rice plants and paddy environments through extraction and purification of PBU from matrix samples using QuEChERS pretreatment. After spraying PBU in paddies, the concentration of PBU gradually decreases in rice plants and paddy water over time, and the final residual concentration is low.
建立水稻及稻田环境中吡丙醚（PBU）残留量的测定方法，测定PBU的残留量并观察其降解动态。
2022年7月，选取浙江省农业科学院的稻田作为试验田，分为空白对照组（不施药）、1倍浓度施药组（1 kg/667 m²）和5倍浓度施药组（5 kg/667 m²），每组面积100 m²。在水稻分蘖初期，1倍浓度和5倍浓度施药组喷施20%硫酸吡丙醚悬浮剂1次，施药后2 h、1、2、3、5、7、11、14、21、28、35、49 d和63 d采集水稻植株、稻田水和土壤样品，施药后98 d采集稻草、田间土壤、糙米和稻壳样品。采用快速、简便、廉价、有效、耐用和安全（QuEChERS）预处理技术对样品中的PBU进行提取和净化，采用超高效液相色谱串联质谱法（UPLC-MS/MS）测定样品中PBU的含量。制备溶剂标准工作溶液和基质标准工作溶液。以PBU浓度（x轴）和峰面积（y轴）拟合线性回归方程，计算基质标准曲线斜率（b）与溶剂标准曲线斜率（b₀）之比，评价样品中PBU的基质效应。根据基质效应，在水稻植株中的PBU添加水平设定为0.005、0.050、5.000、1 000.000 mg/kg，稻田水中为0.005、0.050、2.000、10.000 mg/kg，土壤中为0.005、0.050、2.000 mg/kg，糙米和稻壳中为0.005、0.050、5.000 mg/kg。计算PBU添加回收率和相对标准偏差（RSD），评价UPLC-MS/MS测定PBU含量的有效性。拟合不同采样时间点样品中PBU浓度的一级动力学方程，分析水稻植株、稻田水和土壤中PBU的降解趋势，计算不同样品中PBU的半衰期。
在溶剂和基质条件下，PBU质量浓度在0.000 10.020 0 mg/kg范围内与峰面积呈良好线性关系（r = 0.985 80.999 7，b/b₀ = -0.471.62，所有P值<0.01）。PBU在水稻植株、糙米和稻壳中的基质效应分别为70.26%、65.42%和65.12%，呈基质抑制效应，在土壤中的基质效应为87.06%，呈弱基质效应。不同样品中PBU添加回收率为77.61%100.12%，RSD为1.43%~6.74%，定量限（LOQ）为0.005 mg/kg，添加回收率和RSD符合《农作物中农药残留检测准则》（NY/T 788—2018）要求，验证了UPLC-MS/MS测定方法的有效性。以1 kg/667 m²剂量喷施PBU后，水稻植株中PBU半衰期为6.24 d，稻田水样中为3.43 d。喷施PBU后98 d，糙米和稻壳样品中PBU最终残留量低于LOQ 0.005 mg/kg。以5 kg/667 m²剂量喷施PBU后，水稻植株中PBU半衰期为15.75 d，稻田水样中为7.62 d。喷施PBU后98 d，糙米中PBU最终残留量低于LOQ 0.005 mg/kg，稻壳中PBU最终残留量为0.049 mg/kg。
通过QuEChERS预处理从基质样品中提取和净化PBU，建立了一种简单、准确、精密的UPLC-MS/MS测定方法，用于测定水稻植株和稻田环境中PBU残留量。稻田喷施PBU后，水稻植株和稻田水中PBU浓度随时间逐渐降低，最终残留浓度较低。
