CHCA as a matrix facilitates the ionization of proteins and peptides in a matrix-assisted laser desorption/ionization(MALDI) time-of-flight(TOF) mass spectrometer. The matrix itself also ionizes and so do its adducts....CHCA as a matrix facilitates the ionization of proteins and peptides in a matrix-assisted laser desorption/ionization(MALDI) time-of-flight(TOF) mass spectrometer. The matrix itself also ionizes and so do its adducts. Matrix clusters and adducts interfere with peptide ionization and peptide mass spectrum interpretation, especially at low sample concentrations and within m/z 500-1 000 range. These matrix adducts, especially within m/z 500-1 000, are significantly reduced with addition of ammonium citrate, ammonium sulfate, ammonium benzoate, ammonium bicarbonate, ammonium citrate and potassium dihydrogen phosphate to the matrix and the samples were deposited onto the MALDI target. The reduction of matrix adducts improves peptide ionization and signal-to-noise ratio, which enhances the reliability of database searching.展开更多
以氮肥施用量、磷肥施用量、基质配比为影响因素,以华山松幼苗苗高、地径为试验指标,采用二次通用旋转组合设计方法,在秦岭南坡陕西省宁陕县火地塘林区就华山松容器育苗基质配比及施肥组合方案进行了试验研究。结果表明,各因素对2年生...以氮肥施用量、磷肥施用量、基质配比为影响因素,以华山松幼苗苗高、地径为试验指标,采用二次通用旋转组合设计方法,在秦岭南坡陕西省宁陕县火地塘林区就华山松容器育苗基质配比及施肥组合方案进行了试验研究。结果表明,各因素对2年生华山松幼苗苗高的影响,基质配比最大,P肥施用量次之,N肥施用量最小;对地径影响,基质配比最大,N肥施用量次之,P肥施用量最小。华山松容器育苗基质配比及施肥组合最优方案为每10 kg营养土施用3 g N肥,每100 kg营养土施用3 kg P肥,营养土配比(黄心土∶砂∶羊粪体积比)为4∶2∶3。展开更多
文摘CHCA as a matrix facilitates the ionization of proteins and peptides in a matrix-assisted laser desorption/ionization(MALDI) time-of-flight(TOF) mass spectrometer. The matrix itself also ionizes and so do its adducts. Matrix clusters and adducts interfere with peptide ionization and peptide mass spectrum interpretation, especially at low sample concentrations and within m/z 500-1 000 range. These matrix adducts, especially within m/z 500-1 000, are significantly reduced with addition of ammonium citrate, ammonium sulfate, ammonium benzoate, ammonium bicarbonate, ammonium citrate and potassium dihydrogen phosphate to the matrix and the samples were deposited onto the MALDI target. The reduction of matrix adducts improves peptide ionization and signal-to-noise ratio, which enhances the reliability of database searching.
文摘以氮肥施用量、磷肥施用量、基质配比为影响因素,以华山松幼苗苗高、地径为试验指标,采用二次通用旋转组合设计方法,在秦岭南坡陕西省宁陕县火地塘林区就华山松容器育苗基质配比及施肥组合方案进行了试验研究。结果表明,各因素对2年生华山松幼苗苗高的影响,基质配比最大,P肥施用量次之,N肥施用量最小;对地径影响,基质配比最大,N肥施用量次之,P肥施用量最小。华山松容器育苗基质配比及施肥组合最优方案为每10 kg营养土施用3 g N肥,每100 kg营养土施用3 kg P肥,营养土配比(黄心土∶砂∶羊粪体积比)为4∶2∶3。
