We synthesized a triazine-based structure labeling reagent T-3 and its isotopic labeling reagent T (_D20) -3, and developed a new strategy for the CE-MS analysis. In order to improve the sensitivity of CE-MS method, we synthesized some labeling reagents which had higher ionization efficiency. We synthesized some labeling reagents which had strong alkalinity with tertiary amine group to improve the separation efficiency of CE.

We designed two different types of labeling reagents from T-3 from the length of carbon alkyl chains and made these labeling reagent more hydrophobic. These labeling reagent were desolvation easily and ionization in the ESI.

We hoped to synthesis labeling reagents contain more nitrogen atoms due to the alkalinity enhancement and multi-charges resulted by the nitrogen atoms. This might greatly promote the separation efficiency in capillary electrophoresis and ionization process in mass spectrometry. Since the alkalinity of tertiary amine (pK_b=3~4) was much more stronger than pyridine (pK_b=8.8), which was a little bigger than aniline (pK_b=9.12).  The introducedtertiary nitrogen atoms can enhance its alkalinity as much as possible.

After the synthesis of these two different types of labeling reagents, we needed to evaluate these labeling reagents. The first method, the ionization efficiency of same molar concentration labeling reagent was tested in mass spectrum directly; the second method, we combined the mixture which same amount maltopentaose, maltohexaose and maltoheptaose was labeled by different labeling reagents and T-3. The third method, we tested these new labeling reagent in our strategy for the CE-MS analysis

Table 1 Ionization efficiency of ethyl(T-3), n-propyl, i-propyl, n-butyl, i-butyl labeling reagent (Set ethyl labeling reagent as 100%)

Comparison of maltopentaose, maltohexaose and maltoheptaose labeled by n-propyl labeling reagents and T-3

Acknowledgement: The work was supported by NSFC(No.21275009)