TOF Analysis of Bay
Water surrounding the
Battleship Texas
Presented at: SETAC 2013
South Regional Conference
Work By: Sue D’Antonio, Joan
Stevens, Andre Szczesniewski ,
Lynne Marshall, John Kimmel
and Ken Helmreich
Agilent 6230 TOF LC/MS
TOF and QTOF techniques
(non-target compounds)
• Identifies and differentiates compounds that were
previously “hidden” under background
• Accurate mass TOF instruments:
– Can determine empirical formula based on the mass of
the compound in question (accurate mass)
Novel data mining techniques
Accurate Mass Databases, Mass Profile Processional
Software
• Discover more compounds/contaminants, faster
and with greater precision
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API-TOF Ion Optical Design
Two Stage
Ion Mirror
TOF Mass Analyzer
Effective Flight Path
Length of 2.0m
Beam Shaper
Optically Coupled
Ion Detector
API Ion Source
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Formulae for TOF Performance
922.0092
Resolution = (m/z)/w1/2
1000/0.1 = 10,000
W1/2 = 0.087
923.0121
922/0.087 = 10,597
921.5 922.0 922.5 923.0 923.5 924.0 924.5
m/z, amu
+TOF MS: 5.474 to 5.547 min from steroid2TOFap42.wiff Agilent, subtracted (4.696 to ...
1.16e5
Mass accuracy (mass error)
(1000.001-1000.000)/1000)x106=1 ppm
1.10e5
1.00e5
9.00e4
In te n s ity , c o u n ts
 measured - actual 
Mass accuracy = 
  106
actual


Max. 1.2e5 counts.
289.2159
8.00e4
Epitestosterone
Resolution 6890
7.00e4
6.00e4
meas = 289.2159
5.00e4
4.00e4
actual = 289.2162
271.2051
3.00e4
Therefore: 1 ppm @ 1000 m/z is 0.001Da (1 mDa)
-1.06 ppm
2.00e4
269.1893
287.1997
1.00e4
0.00
120
140
160
180
200
220
240
260
m/z, amu
280
300
320
340
360
380
400
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How Much Accuracy is Needed?
(Newer concept for LC/MS: ppm accuracy)
Reserpine (C33H40N2O9) has a protonated ion at 609.28066
Single quad reports mass to +/- 0.1 = 165 ppm
Number of possible formulas using only C, H, O & N:
• 165 ppm
209
• 10 ppm
13
• 5 ppm
7
• 3 ppm
4
• 2 ppm
2
Accurate mass reduces number of candidates and risk of
investing effort with the wrong molecule
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SPE Sample Prep
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Analysis of Water Samples
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Choose Your Elements: Find Compounds by
Molecular Feature and Generate Formulae
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Molecular Feature Generator
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Compound Chromatogram
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Deductive Compound Choices
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Conclusions
Utilizing Agilent’s Time of Flight accurate mass, high resolution,
superior isotopic fidelity and the unique features of Mass Hunter
software, such as Molecular Feature Extractor and Molecular
Formula Generator, we were able to identify over 100
compounds found in the samples.
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