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Characterization and Quantitation of Supplement Samples Using TGA‐MS
Providing Solutions for Gas Analysis
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Abstract

Thermal analysis techniques, such as thermogravimetric analysis (TGA), are commonly used by chemists and material scientists to provide information about the thermal properties and chemical composition of a sample. 
Evolved gas analysis (EGA) allows for chemical identification and quantitation of the gases and vapors generated by various analytical techniques, and can answer additional questions when combined with the thermal curve data from a TGA.
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The interface must be capable of high temperature operation and provide fast sample‐transit through a chemically inert pathway
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An Extrel MAX300‐EGA, quadrupole mass spectrometer, was used in conjunction with a NETZSCH TG 209 F1 Libra thermobalance to characterize and quantify the breakdown of common nutritional supplement samples. © Copyright 2013 Extrel CMS, LLC
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Evolved Gas Analysis
 The analysis of the chemical composition of gases and vapors generated by an analytical technique or chemical process

Thermal analyzers

Reaction monitoring

Headspace analysis

Continuous flow systems (microreactors)
 Traditional EGA

Technologies
GC, GC‐MS, FTIR, MS
© Copyright 2013 Extrel CMS, LLC
Thermal Analysis
 Thermogravimetric
Analysis (TGA)
 Differential
Scanning
Calorimetry (DSC)

Both provide information about the thermal characteristics and
chemical composition of solid and liquid samples
© Copyright 2013 Extrel CMS, LLC
4
+ Applications of TGA‐MS Technology
 Pharmaceuticals
 Thermoplastics
 Materials Science
 Organic Chemistry
 Natural Product Analysis
 Synthesis Studies
 Pilot Scale Process/ R&D
 QA/ QC
© Copyright 2013 Extrel CMS, LLC
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Challenges for EGA
 Sample transfer
High Temperature
 Condensation/ particulates
 Chemical Interactions


Sensitivity

Cycle Time Resolution 
Quantitation

Data Integration
© Copyright 2013 Extrel CMS, LLC
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NETZSCH TG 209 F1 Libra

Vacuum‐Tight

Automatic Sample Changer
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Sample Temperatures up to 1,100°C

Mass resolution of 0.1 µg
© Copyright 2013 Extrel CMS, LLC
MAX300‐EGA Mass Spectrometer

Optimized for Evolved Gas Analysis

Designed for Benchtop Operation
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2 m Heated, Differential‐Pumped Inlet
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© Copyright 2013
Extrel CMS, LLC
200, 300 and 400°C options available
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Extensive compound Library
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Configured to accept external I/O, like the Start‐of‐Heating signal from a TGA
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Questor5 Control Software can trend and store data or export 8
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The EGA Inlet
•
Heated‐ 200, 300, or 400°C
•
Differentially pumped
A. The Interface for the NETZSCH TG 209 F1 Libra TGA
B. The Interface for use with TA Instrument's Q5000IR TGA
C. The Interface for use with a Perkin Elmer Pyris 1 TGA
D. The Transfer line is designed to eliminate cold spots and pull sample quickly into high vacuum  The inlet of the MAX300‐EGA is © Copyright 2013 Extrel CMS, LLC
built to interface with all commercial and custom continuous flow systems.
MAX300‐EGA Mass Spectrometer
© Copyright 2013 Extrel
CMS, LLC

19 mm Quadrupole

1‐200 amu

Dual Detector

Faraday Plate

Electron Multiplier
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Dynamic Range: 100 % down to 10 ppb 
Quantitative analysis performed at 0.4 seconds/ component 
Precession: ± 0.0025 on 1 % argon with no interference

Stability: ± 0.005 over 30 days on 1 % argon
10
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Data Integration
 Equipped to Import digital syncing commands
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Start‐of‐Heating
 Several Options for Data Export‐ In Real Time or post acquisition

.xls

NIST

ascii
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Custom formats supported
© Copyright 2013 Extrel CMS, LLC
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TGA‐MS with the MAX300‐EGA
© Copyright 2013 Extrel CMS, LLC
Reaction Monitoring- Headspace Analysis/ microreactors
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System to which a researcher has access to a continuous gas flow with
a dynamic composition. Changes within the evolving fraction provide
insight into conditions within the reaction vessel.
© Copyright 2013 Extrel CMS, LLC
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Quantitative Analysis
• 20 μg of Water
detected and
quantified by the
MAX300-EGA
• Similar mass
values measured
by both systems
• Separate
Quantitation of
CO/ CO2
• Faraday only
detection method
© Copyright 2013 Extrel CMS, LLC
MAX300‐EGA
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Component
Water
Carbon Monoxide
Carbon Dioxide
Sum
TGA Data
Component
Water
Carbon Monoxide
Argon
Carbon Dioxide
Mass Loss (µg)
1
2
20.82
57.39
32.05
20.82
89.45
21.11
89.56
3
139.01
139.01
137.90
m/z 18 m/z 28 m/z 40 m/z 44 Sens
100
1
100
1.27
100
1
11
100
1.43
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Polystyrene
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0.94 mg of sample were used
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Furnace was heated to over 600°C
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Reduced eV, "Soft" Ionization
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Mass spec indicated the presence of Styrene, CO2, H2O
© Copyright 2013 Extrel CMS, LLC
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Recorded Spectrum of Polystyrene
© Copyright 2013 Extrel CMS, LLC
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Recorded Spectrum of Methyl Styrene
© Copyright 2013 Extrel CMS, LLC
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Polystyrene Dimer Trend
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Recorded Spectrum of the Polystyrene Dimer
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Vitamin C
 Ascorbic Acid  Common Dietary Supplement
 3 Sources:
 2 OTC Manufactured Supplements
 Analytical Purity (Sigma)
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Thermal Decomposition of Vitamin C
A
C
B
(AG)
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5 mg of Sample
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Heated to 800°C @ 10K/min
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20 ml/min
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3 stages of Decomposition
 191‐268°C
 268‐504°C
 504‐800°C
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
195
200
205
210
215
220
225
230
235
240
245
250
MS Signal Intensity
50
54
58
62
66
70
74
78
82
86
90
94
98
102
106
110
114
118
122
126
130
134
138
142
147
153
160
165
170
175
180
184
189
195
200
206
211
217
222
229
235
242
249
MS Signal Intensity
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Spectrum of Mass Loss Gases
1.60E-04
1.40E-04
1.20E-04
1.00E-04
8.00E-05
6.00E-05
4.00E-05
2.00E-05
0.00E+00
A
m/z
0.0008
0.0007
0.0006
0.0005
0.0004
0.0003
0.0002
0.0001
0
C
m/z
(AG)
Survey Scan Delta, C – A, with furfural identified as the likely component by Questor5 linked to the NIST database 0.13
0.11
0.09
0.07
0.05
0.03
0.01
-0.01
-0.03
65
69
73
77
81
85
89
93
97
101
105
109
113
117
121
125
129
133
137
141
145
149
153
157
161
165
169
173
177
181
185
189
193
197
201
205
209
213
217
221
225
229
233
237
241
245
249
MS Signal Intensity
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m/z
96
100
39
50
O
O
29
0
10
(m ainlib) Furfural
42
25
13
20
30
40
67
50 53
50
60
70
80
90
100
110
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Furfural Comparison Trends
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Conclusions
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Connected to NETZSCH TG 209 F1 Libra, the MAX300‐EGA was able to measure the gases generated during the decomposition of various samples
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The quantitative analysis of the off‐gas from Calcium Oxalate samples demonstrates the ability of the system to separately measure the contributions of multiple compounds to a single mass loss
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Validation on polystyrene samples showed that relatively large molecules pass through the high temperature sample line
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Evolved gases from different Vitamin C sources were compared and differences in the furfural concentrations were observed by matching data against the NIST library
© Copyright 2013 Extrel CMS, LLC
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MAX300 Quadrupole Mass Spectrometers
Providing Solutions for Gas Analysis
© Copyright 2013 Extrel CMS, LLC