Normalized Collision Energy Technology碰撞能量.PDF

mass spectrometry PRODUCT SUPPORT BULLETIN PSB 104 Page 1 of 2 Normalized Collision EnergyTM Technology The resonance excitation process is used for inducing fragmentation in an ion trap. As the amplitude of the applied RF voltage increases, the parent ion dissociates to fragment ions over a narrow range of energies. The collision energy needed to achieve optimum fragmentation ef?ciency has been shown to follow a linear correlation with m/z (Figure 1). Increasing the amplitude further does not signi?cantly change the fragmentation pattern. The collision energy is set using a simple scale of 0-100%. Under the previous regime, setting a value of 30 would apply 30% of the available 5V regardless of the mass of the ion. Figure 2 shows the effect that this would have for three different ions. For an ion at m/z 200, too much energy would be applied causing the ion and its fragments to be ejected from the trap. For an ion at m/z 800 the energy would be Figure 1 correct. Not enough energy, however, would be applied for an ion at m/z 1800 and it would not be fragmented suf?ciently. The Normalized Collision Energy principle auto- matically compensates for this mass dependency. Using a setting of 30% collision energy on an ion at m/z 1800 applies more energy than to an ion at m/z 800. Figure 2 The effect of using Normalized Collision Energy on the same three ions from Figure 2 is shown in Figure 3 below. A collision energy of 30% is now optimized for a wide range of masses. Part of Thermo Fisher Scienti?c PRODUCT SUPPORT BULLETIN 104 Page 2 of 2 Normalized Collision Energy Technology Figure 3 Data Dependent? experiments make practical use of Normalized Collision Energy. Using the conventional method, a single value cannot be chosen for the collision energy that will produce good data for compounds with widely different masses. This is particularly relevant when analyzing protein digests where peptides have masses that range from below 200 Da to over 2000 Da. Normalized Collisi