19
V 模式分辨率
V_RESCHECK001 272 (6.086) 100
956.69 956.36
TOF MS ES+ 5.84e3
Res > 11000
956.87
%
956.20
957.03
957.20
957.36 956.02 957.53 957.69
0 955
956
957
m/z 958
©2007 Waters Corporation
26
同位素模型
©2007 Waters Corporation
27
实例：标称质量数作组成推断
Nominal mass measurement doesn’t provide data specificity At m/z609, with 0.1Da error around mass, 2214 possible combinations Using wide range of elements:
©2007 Waters Corporation 8
质量准度
真实质量
测量质量 偏差
= 400.0000
= 400.0020 = 0.0020
质量误差 ppm =
0.002
400
x 106
= 5 ppm
©2007 Waters Corporation
9
高、低分辨率的差异
©2007 Waters Corporation
— C500H1000N20O20S10Cl10Br10
©2007 Waters Corporation
©2007 Waters Corporation
17
正负离子化模式切换
正负离子化模式切换在 300毫秒之内 对未知物分析鉴别非常 适用
同样也能用LockSpray
得到准确质量数
©2007 Waters Corporation
18
Q-Tof Premier 结构简图
©2007 Waters Corporation
%
15.00
20.00
25.00
30.00
35.00
40.00
45.00
Sample TIC
%
50.00 1: TOF MS ESBPI 2.57e5
0 0.00 5.00 10.00 POSNEGPASSIFORADRE_KD005_280204_48
15.00
20.00
25.00
30.00
35.00
O
N
S
H O
N S N N H N
O S
N
N H
硫代物
[M+H]+ 344.1433
质量差 = 36 mDa 醛基化物
[M+H]+ 344.1069
©2007 Waters Corporation 22
MSn 怎么办 ?
O O N N S N H
H+ N N H
m/z 226.0902 ( 4.1 ppm)
12
不同分辨性能对液质分析的影响
©2007 Waters Corporation
13
Z Spray Source
©2007 Waters Corporation
14
LockSprayTM 简单实现精确质量测定
LockSpray专利技术使精 确质量测定能简单实现 使得不必过分依赖于实验室 环境和条件的稳定，每次采 集都同时用一个已知的、确 定的质量数进行校正 LockSpray是Waters飞 行时间质谱产品所独有的， 而且是标准配置
957.01 956.17
%
957.17
957.34 956.01
957.51 957.67
0 955
956
957
m/z 958
Bovine insulin, Resolution >22,000
©2007 Waters Corporation 21
应用实例 ：贝雷拉唑代谢物分析
O O O
O O
N N H
10
准确质量带来的差异
(assuming elements C50H100N5O5S2)
gradtest003 101 (4.718) 100
311.1
1: TOF MS ES+ 1.88e4
标称质量（Nominal mass）谱图 (如用四极杆或离子阱得到的数据) ~50ppm tolerance @ m/z 311.0814
©2007 Waters Corporation
15
液相的样品通路不会影响参比路的离子化
PC 2MG/ML
POSNEGPASSIFORADRE_KD005_280204_48 100
Reference
2: TOF MS ESTIC 1.00e5
0 0.00 5.00 10.00 POSNEGPASSIFORADRE_KD005_280204_48 100
40.00
45.00
6.0e-1
Sample UV
50.00 3: Diode Array 330 Range: 7.291e-1
AU
4.0e-1
2.0e-1
0.0 0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
Time 50.00
©2007 Waters Corporation
Reserpine, 10pg, W Optics
TOF MS ES+ 609.3 0.20Da 5.57e3
AS012 100
S/N:PtP=288.19
TOF MS ES+ 609.3 0.20Da 4.78e3
%
0 1.00 2.00 3.00 4.00 5.00
Time
%
0 1.00 2.00 3.00 4.00 5.00
©2007 Waters Corporation
5
简单的例子
? 分子量 =
28
©2007 Waters Corporation
6
简单的例子
CO = 27.9949
N2
C2H4
=
=
28.0061
28.0313
这些分子的整质量数相同，但是准确质量不同 单靠整质量数不能判定组成 需要尽量准确的质量数才能尽量准确的判断
Waters飞行时间质谱技术及应用
©2007 Waters Corporation
Waters Q-Tof 质谱的历史
1996, 世界上第一台Q-Tof质谱 1998, Q-Tof 2 2000, Q-Tof micro and Q-Tof Ultima 2004, Q-Tof Premier 2007, HDMS（High Definition Mass Spectrometer）
— C500H1000N20O20S10Cl10Br10
©2007 Waters Corporation
28
实例：不开启i-FIT过滤功能 (5ppm)
At m/z609, with 5ppm error around mass, 134 possible combinations Using wide range of elements:
Time
相同量的reserpine
W模式与v模式，灵敏度相同
©2007 Waters Corporation 25
准确质量数是否足够？
Summary Conclusion • High mass accuracy (<1 ppm) alone is not enough to exclude false positives • The use of isotopic abundance patterns as another filter can further remove >95 % of false candidates Final Quote…. “Assuming that ion species are fully resolved (either by chromatography or by high resolution mass spectrometry), we conclude that a mass spectrometer capable of 3 ppm mass accuracy and 2% error for isotopic abundance patterns outperforms mass spectrometers with less than 1 ppm mass accuracy or even hypothetical mass spectrometers with 0.1 ppm mass accuracy that do not include isotope information in the calculation of molecular formulae”
1: TOF MS ES+ 1.88e4
准确质量（Exact Mass）谱图 （如飞行时间得到的数据） 3ppm tolerance @ m/z 311.0814 3 Possible Results
%
312.0850
0 290
m/z 295 300 305 310 315 320 325 330
©2007 Waters Corporation
©2007 Waters Corporation