不同研磨条件对玉米样品粉碎制备效果的影响

目的研究不同研磨条件粉碎玉米样品的效果,科学制备样品。方法使用平行研磨仪对玉米样品进行粉碎,分别考察不同重量、不同研磨时间、不同循环次数下粉碎后的玉米通过20目、40目、60目标准筛的过筛率,幵采用QuEChERS-超高效液相色谱-串联质谱法测定不同粉碎条件的样品添加回收结果,来辅助评价研磨效果。结果 50g玉米样品研磨60s循环1次后过20目筛率可达71.8%,未过筛直接添加26种农药回收率为74.4%～114.0%除甲胺磷外,相对标准偏差(relative standard deviation,RSD)为1.8%～8.5%];100 g玉米研磨30 s循环2次后过20目筛率为58.0%,未过筛直接添加26种农药回收率为77.7%～118.1%(除甲胺磷外, RSD为1.5%～10.3%)。结论实验使用的平行研磨仪适用于多个玉米样品同时粉碎制备,相比传统研磨仪只能逐个粉碎样品的处理效率得到显著提高,一次性研磨50～100 g玉米60 s后即可满足科学制备检测样品的需要。

Effect of different grinding conditions on the smash effect of corn sample

Objective To investigate the effect of different grinding conditions on the smash effect of corn sample, in order to prepare samples scientifically. Methods The corn sample was pulverized by a parallel grinder, the sieving rate of the pulverized corn through 20-mesh, 40-mesh, and 60-mesh standard sieves under different weights, different grinding times, and different cycle times was examined, and the standard recovery rates under different pulverization conditions were determined to assist in the evaluation of the grinding effect by QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry. Results The 50 g corn sample was ground for 60 s once and then passed through a 20-mesh sieve for 71.8%. The recovery rate of 26 pesticides added directly without screening was 74.4%?114.0% except for methamidophos, the relative standard deviation (RSD) was 1.8%?8.5%]; The 100 g corn sample was ground for 30 s for 2 times and then passed through a 20-mesh sieve for 58.0%. The recovery rate of 26 pesticides without screening was 77.7%?118.1% (except for methamidophos, RSD was 1.5%?10.3%). Conclusion The parallel grinder used in the test is suitable for simultaneous pulverization of multiple corn samples, and obviously improve the efficiency compared to traditional methods which can only grind samples one by one. Grinding 50?100 g corn for 60 s at a time can meet the needs of scientific preparation of test samples.