Experience and Tips in LC-MS/MS Quantification

1
Experience and Tips in LC-MS/MS Quantification

• Summary
• The process of LC-MS/MS Quantification analysis
  is very important. If you want to get the exact
  data from your experiment, you can follow these
  tips to get it. Here I will share the experience
  in LC-MS/MS method with you.

2

• Body
• There are six steps you have to do.
• The first step---Q1 Scan. This is to ensure the
  mass of the precursor ion. We will select the
  polarity, which will be analyzed, ESI/APCI
  according to the nature of the test compound. And
  then we choose the scanning range and time,
  depending on molecular weight. There is one thing
  you have to keep in mind that the mass of the
  precursor ion should be more accurate.

3

• The second step is product ion scan. This is to
  determine the mass to charge ratio of ion. After
  the first step, we will get the high-quality
  chart of MS2, the most proper strength of the
  parent ion is one third or a quarter of the peak
  in the chart.
• The next step is optimizing compound parameters.
  We can build MRM ion pairs according to the
  parent ion and ion we chose before. And the
  analysis time of each pair should be allotted
  properly. And then we optimize parameters of
  compound and CAD. The MRM method is initially
  established. In order to get the most exact
  result, we generally optimize twice.

4

• The following step is to change the method (that
  is to say we can change the continuous feed
  volume method to LC-MS method). In this step, we
  have to turn off all mass spectrometry interface
  and MS system, and then to activate LC-MS and MS
  equipment.
• The fifth step is optimizing source parameters
  with FIA. We can dulute the sample solution to
  100 times or 1000 times. After that we can
  process the FIA analysis. To click the
  Quantitative Optimization twice. According to the
  guidelines to start the automatic optimization.

5

• The following step is to change the method (that
  is to say we can change the continuous feed
  volume method to LC-MS method). In this step, we
  have to turn off all mass spectrometry interface
  and MS system, and then to activate LC-MS and MS
  equipment.
• The fifth step is optimizing source parameters
  with FIA. We can dulute the sample solution to
  100 times or 1000 times. After that we can
  process the FIA analysis. To click the
  Quantitative Optimization twice. According to the
  guidelines to start the automatic optimization.