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超高效液相色谱-串联质谱法对比11种净化方式对当归中50种农药残留检测的影响 被引量:9
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作者 刘志荣 《应用化学》 CAS CSCD 北大核心 2019年第8期968-976,共9页
采用超高效液相色谱-串联质谱仪(UPLC-MS/MS)同时测定当归药材中50种农药残留,对比了11种净化方式对检测结果的影响,筛选出最有效的基质净化方法。以回收率为考察指标,评估了不同基质净化方法对当归中多农残的提取净化效果,最终确定样... 采用超高效液相色谱-串联质谱仪(UPLC-MS/MS)同时测定当归药材中50种农药残留,对比了11种净化方式对检测结果的影响,筛选出最有效的基质净化方法。以回收率为考察指标,评估了不同基质净化方法对当归中多农残的提取净化效果,最终确定样品经乙腈提取,NaCl净化,在电喷雾正负离子扫描、依赖保留时间的动态多反应监测模式(dMRM)下,以基质匹配内标法定量。结果表明,50种农药在NaCl净化法下回收率最高,在各自的浓度范围内线性关系良好(R^2>0.99);3个添加水平(10、50、100μg/kg)下,大多数农药的回收率为70.1%~117.7%,相对标准偏差(RSD,n=6)不大于20.0%,50种农药的定量限为1.0~20.0μg/kg。该方法为当归中准确、高效、经济的检测目标物提供了可靠依据。 展开更多
关键词 基质净化方法 农药残留 当归
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cDNA cloning, prokaryotic expression and purification of rat α-synuclein 被引量:1
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作者 Xin LI Yao-Hua LI Jun-Yan HAN Shun YU Biao CHEN 《Neuroscience Bulletin》 SCIE CAS CSCD 2006年第1期29-33,共5页
Objective To clone the cDNA of rat α-Syn gene, investigate its prokaryotic expression and produce purified recombinant rat α-Syn protein. Methods Rat α-Syn cDNA was amplified from the rat brain total RNA by RT-PCR ... Objective To clone the cDNA of rat α-Syn gene, investigate its prokaryotic expression and produce purified recombinant rat α-Syn protein. Methods Rat α-Syn cDNA was amplified from the rat brain total RNA by RT-PCR and was cloned into pGEX-4T-1, a prokaryotic expressing vector. The recombinant plasmid containing rat α-Syn gene was transformed into E. Coli BL21 to express a fusion protein with rat α-Syn protein tagged by glutathione-S-transferase (GST). The fusion protein was then cleaved by thrombin during passing through the GST-agarose 4B column to release the recombinant rat α-Syn protein. The recombinant rat a-Syn protein was further purified using Superdex S200 gel filtration. Results DNA sequencing confirmed that the cloned cDNA contained 420 base pairs encoding 140 amino acids, which was identical to the reported amino acid sequence of rat α-Syn. After transformation, the recombinant plasmid pGEX-ra-Syn expressed a soluble protein that was inducible by IPTG. The purified recombinant protein was shown to be single band on SDS-PAGE, with a molecular size of around 18000, which was identical to the reported molecular size of rat α-Syn. Western blot analysis demonstrated that the recombinant protein was recognized by specific antibody against α-Syn. Conclusion The rat α-Syn gene was successfully expressed in prokaryotic expression system and highly purified rat α-Syn recombinant protein was produced. 展开更多
关键词 Α-SYNUCLEIN RAT recombinant protein PURIFICATION
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