利用QuEChERS(quick,easy,cheap,effective,rugged,safe)结合超高效液相色谱串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)建立同时检测禽蛋及其制品中42种农药及其代谢物残留的检测方法...利用QuEChERS(quick,easy,cheap,effective,rugged,safe)结合超高效液相色谱串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)建立同时检测禽蛋及其制品中42种农药及其代谢物残留的检测方法。以体积分数1%的乙酸乙腈为提取溶剂,加入NaCl除水后,经多功能针式过滤器至进样小瓶中,以体积分数为0.1%甲酸水溶液和5 mmol/L甲酸铵甲醇溶液作为流动相,采用UPLC-MS/MS方法检测。结果表明,各农药及代谢物在0.5~100μg/L范围内线性关系良好,相关系数大于0.9900,检出限为0.01~0.5μg/kg,样品加标回收率为74.13%~113.22%,相对标准偏差(relative standard deviation,RSD)为0.98%~14.29%(n=6)。建立的QuEChERS-UPLC-MS/MS方法可同时检测42种目标物,回收率好、精密度高、检出限低、且分析时间短,能够满足禽蛋及其制品中多种农药及其代谢物的同时检测。展开更多
目的建立高效液相色谱法检测肉及肉制品中甲醛含量的分析方法。方法用水蒸气蒸馏法提取,2,4-二硝基苯肼衍生化。优化蒸馏体积、最佳衍生条件。以甲醇和水为流动相、流速0.5mL/min、检测波长338nm的高效液相色谱条件进行测定。结果最终...目的建立高效液相色谱法检测肉及肉制品中甲醛含量的分析方法。方法用水蒸气蒸馏法提取,2,4-二硝基苯肼衍生化。优化蒸馏体积、最佳衍生条件。以甲醇和水为流动相、流速0.5mL/min、检测波长338nm的高效液相色谱条件进行测定。结果最终确定蒸馏体积为300mL,最佳衍生条件为55℃,30min。该方法在0~20mg/L浓度范围内线性关系良好(r2=0.9994),检出限0.1mg/kg,定量限为0.35mg/kg。在5、10、30mg/kg3个水平加标,测得的加标回收率为97.4%~107.8%,相对标准偏差(relative standard deviation,RSD)为3.77%~5.13%。结论用建立的方法对市售产品进行检测分析,结果可以满足肉及肉制品的检测需求。展开更多
The present study aims to plumb blockage of the deep-sea mining pump transporting large particles with different shapes. A numerical work was performed through combining the computational fluid dynamics(CFD) technique...The present study aims to plumb blockage of the deep-sea mining pump transporting large particles with different shapes. A numerical work was performed through combining the computational fluid dynamics(CFD) technique and the discrete element method(DEM). Six particle shapes with sphericity ranging from 0.67 to 1.0 were selected. A velocity triangle is built with the absolute, relative, and circumferential velocities of particles. Velocity triangles with absolute velocity angles ranging from 90° to 180° prevail in the first-stage impeller. With declining sphericity, more particles follow the velocity triangle with absolute velocity angles ranging from 0° to 90°, which weakens the ability of particles to pass through the flow passage. Furthermore, the forces acting on the particles traveling in the impeller passage are analyzed. Large particles, especially non-spherical ones, suffer from high centrifugal force and therefore move along the suction surface of the impeller blades. Non-spherical particles undergo great drag force as a result of large surface area. The distribution of drag force angles is featured by two peaks, and one vanishes due to blockage.As particle sphericity declines, both magnitude and angle of the pressure gradient force decrease. Variation of the drag force and the pressure gradient force causes clockwise deflection of the centripetal force, resulting in deflection and elongation of particle trajectory, which increases the possibility of blockage.展开更多
文摘利用QuEChERS(quick,easy,cheap,effective,rugged,safe)结合超高效液相色谱串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)建立同时检测禽蛋及其制品中42种农药及其代谢物残留的检测方法。以体积分数1%的乙酸乙腈为提取溶剂,加入NaCl除水后,经多功能针式过滤器至进样小瓶中,以体积分数为0.1%甲酸水溶液和5 mmol/L甲酸铵甲醇溶液作为流动相,采用UPLC-MS/MS方法检测。结果表明,各农药及代谢物在0.5~100μg/L范围内线性关系良好,相关系数大于0.9900,检出限为0.01~0.5μg/kg,样品加标回收率为74.13%~113.22%,相对标准偏差(relative standard deviation,RSD)为0.98%~14.29%(n=6)。建立的QuEChERS-UPLC-MS/MS方法可同时检测42种目标物,回收率好、精密度高、检出限低、且分析时间短,能够满足禽蛋及其制品中多种农药及其代谢物的同时检测。
文摘目的建立高效液相色谱法检测肉及肉制品中甲醛含量的分析方法。方法用水蒸气蒸馏法提取,2,4-二硝基苯肼衍生化。优化蒸馏体积、最佳衍生条件。以甲醇和水为流动相、流速0.5mL/min、检测波长338nm的高效液相色谱条件进行测定。结果最终确定蒸馏体积为300mL,最佳衍生条件为55℃,30min。该方法在0~20mg/L浓度范围内线性关系良好(r2=0.9994),检出限0.1mg/kg,定量限为0.35mg/kg。在5、10、30mg/kg3个水平加标,测得的加标回收率为97.4%~107.8%,相对标准偏差(relative standard deviation,RSD)为3.77%~5.13%。结论用建立的方法对市售产品进行检测分析,结果可以满足肉及肉制品的检测需求。
基金financially supported by the Science and Technology Plan Project of State Administration for Market Regulation of China (Grant No. 2021MK060)the National Key Research and Development Program of China (Grant No. 2021YFC2801600)+1 种基金the Postgraduate Research and Practice Innovation Program of Jiangsu Province (Grant No. KYCX20_3082)the Science and Technology Innovation Project from China State Shipbuilding Corporation Limited。
文摘The present study aims to plumb blockage of the deep-sea mining pump transporting large particles with different shapes. A numerical work was performed through combining the computational fluid dynamics(CFD) technique and the discrete element method(DEM). Six particle shapes with sphericity ranging from 0.67 to 1.0 were selected. A velocity triangle is built with the absolute, relative, and circumferential velocities of particles. Velocity triangles with absolute velocity angles ranging from 90° to 180° prevail in the first-stage impeller. With declining sphericity, more particles follow the velocity triangle with absolute velocity angles ranging from 0° to 90°, which weakens the ability of particles to pass through the flow passage. Furthermore, the forces acting on the particles traveling in the impeller passage are analyzed. Large particles, especially non-spherical ones, suffer from high centrifugal force and therefore move along the suction surface of the impeller blades. Non-spherical particles undergo great drag force as a result of large surface area. The distribution of drag force angles is featured by two peaks, and one vanishes due to blockage.As particle sphericity declines, both magnitude and angle of the pressure gradient force decrease. Variation of the drag force and the pressure gradient force causes clockwise deflection of the centripetal force, resulting in deflection and elongation of particle trajectory, which increases the possibility of blockage.
