(6-Bromopyridin-2-yl)acetonitr

HPLC入门问题FAQ

段质量。 11.怎样在质谱的图谱上确定单一同位素峰和平均同位素峰? 在分辨率低的质谱图谱上，所显示的峰一般是平均同位素峰。但目前常用的质谱方法（比如 MALDI-TOF ）分辨率一般都很高，一般的小分子（比如肽段）常含有 4 到 5 个同位素峰，其中分子量最小的那个就是单一同位素峰。但是，当用质谱检测大分子（比如完整蛋白质）时，同位素峰的数目很多，难以在图谱上区分。在这种情况下，使用平均同位素质量会比较更有意义。 12.同位素峰之间一定是相差 1 Da 吗？ 同位素肽段的质量（m

Determination of Polyamines as Their Benzoylated Derivatives by HPLC

detection of other compounds ( 6 , 9 ). Acetonitrile-water mixtures, also used isocratically, can improve sensitivity ( 11 ). The characteristics of the assay have been extensively investigated ( 4 , 7 , 12 ).   Fig. 1.  The reaction

Two‐Step, One‐Pot Synthesis of Inosine, Guanosine, and 2′‐Deoxyguanosine O6‐Ethers via Intermediate O6‐(Benzotriazol‐1‐yl) Derivatives

) and Cs2 CO3 under a nitrogen atmosphere. Conversion to the O 6 ?(benzotriazol?1?yl) ethers occurs within about 10 min for inosine, and within about 60 min for guanosine and 2??deoxyguanosine. Then, for reaction with alcohols, the reaction mixture