主题：【讨论】请教质谱操作——为什么每次测试前要标定？如何标定? 洋鬼子解释不清

Hi,

因为每次重新操作仪器得时候，仪器各部分得电压都需要一个稳定得过程，并且都会有一定的偏差。 假设你用的是Time of flight mass spectrometry. The acceleration voltage will affect the flight time of the ions. THere is a formula relating the Total of flight time 'T' with the mass of the ions 'm' :
          T= A*m^(1/2)+B
where A and B are two parameters which are related to the instrument conditions, mostly to the voltages applied on the instrument.
So everytime when you start the instrument, the parameters of A and B are different. We can use two known masses to calibrate the instruments, basically that is to determine these two parameters of A and B. All these are actually done by the software. As long as you follow the procedure of the software, the instrument will be calibrated automatically.

There are normally some standard samples (known masses) to calibrate the instument. It depends on what kind of instrument you are using. But the fundamental principle from the point view of physics is just what I have briefly said.

原文由 yhe_zh 发表:
我做的是测试碳材中的氢的多少。每隔一点时间测试时都要重新标定质谱。过去没做过这种测试，只是看组里的人这么做就依葫芦画瓢，但是不明就里，而且组里的洋鬼子每个人的标定都不相同，也都说不清缘由——特回来请教大家

我们用的是四极杆质谱，我不知道您是怎么标定的，用什么标定的，我对这个很感兴趣，请和我联系哦，谢谢！QQ：945095995，加我为好友就说质谱。