电喷雾飞行时间质谱法研究溶液pH值对醋氨己酸锌络合结构的影响

EFFECT OF SOLUTION pH VALUE ON THE CHELATION STRUCTURE OF ZINC ACEXAMATE BY ELECTROSPRAY IONIZATION MASS SPECTROMETRY

目的 考察不同 pH值条件下醋氨己酸锌络合结构的稳定性。 方法 测定不同 pH值醋氨己酸锌溶液的电喷雾离子化 /飞行时间质谱 ,研究其络合结构的稳定性。结果 证明醋氨己酸锌络合结构在 pH值为 2 5 4时最稳定 ,且在此 pH值有一定的缓冲作用。根据质谱数据 ,发现在此 pH条件下 ,醋氨己酸锌较易形成 (M +ZnY) + (Y =CH3 CONH(CH2 ) 5COO-)和 (2M +Na) + 离子。结论 醋氨己酸锌能减低胃的酸度 ;可进一步形成多聚体 ;对于胃酸分泌过多的病人 ,它与质子泵阻断剂、胃酸抑制剂的联合用药是合理的。

AIM To study the effect of solution pH value on the chelation structure of zinc acexamate. METHODS A series of samples at different solution pH values were prepared by 10% HCl or 1 mol·L -1 NH 3·H 2O. Then API/TOFMS with electrospray ion source was applied to assay the samples. The nitrogen curtain gas and nebulizer gas were adjusted to a constant flow rate of 0 6 μL·min -1 and 2 μL·min -1 respectively. Samples were infused into the electrospray interface using a 500 μL syringe pump at a flow rate of 5 μL·min -1 . Mass spectra were acquired in positive ion modes by scanning over the range of m/z 100～ 1 000 . RESULTS The chelation structure of zinc acexamate is stable at pH 2 54 and it can be easy to form the ion (M+ZnY) + (Y=CH 3CONH(CH 2) 5COO -) and (2M+Na) + in this condition. CONCLUSION The drug is an effective antiulcer agent. It may decrease the acidity of stomach juice, and form a polymer to protect the ulcer.