Optimization of Phthalate Analysis by
Gas Chromatography-Mass
Spectrometry Using Computer
Modeling Software
Dan Li, Rebecca Stevens, Chris English,
Jack Cochran, and Jason Thomas
Restek Corporation
Phthalates
Are All Phthalates Bad
Are All Phthalates Safe
GC-MS Analysis of Phthalates
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Stationary Phase
Oven Temperature Program
Flow Rate
Carrier Gas
Column Dimension
Resolution
Detector
Pro EZGC Method Development
FREE
Select Stationary Phases for
Phthalates
Available
in EZGC®
Select Stationary Phases for
Phthalates
Rtx®-440
Rxi®-XLB
Rtx®-CLPesticides
Rxi®-35Sil MS
Rtx®-50
Rxi®-5ms
Rtx®-CLPesticides2
Select Stationary Phases for
Phthalates
Rtx®-440
30 m x 0.25 mm x 0.25 µm
150 °C (hold 0.8min) to 200 °C @ 5 °C/min to 275 (hold 2min) @ 3 °C/min
Shimadzu GC-MS QP2010 Plus
48 cm/sec
Choose Stationary Phases for
Phthalates
Name
Listed
Rtx®-440
Peaks
1
dimethyl phthalate
EPA 8061, EPA Priority
30 m x 0.25 mm x 0.25 µm
2
diethyl phthalate
EPA 8061, EPA Priority,
EU
3
benzyl benzoate
Internal Standard
4
diisobutyl phthalate
EPA 8061
5
di-n-butyl phthalate
EPA 8061, EPA Priority
6
bis(2-methoxyethyl) phthalate
EPA 8061
7
8
9
EPA, EU list
bis(4-methyl-2-pentyl)phthalate
isomer 1
bis(4-methyl-2-pentyl)phthalate
isomer 2
Shimadzu GC-MS QP2010 Plus
EPA 8061
bis(2-ethoxyethyl) phthalate
EPA 8061
10
diamyl phthalate
EPA 8061
11
di-n-hexyl phthalate
EPA 8061
12
butyl benzyl phthalate
EPA 8061, EPA Priority,
EU
13
hexyl 2-ethylhexyl phthalate
EPA 8061
14
bis(2-n-butoxyethyl) phthalate
EPA 8061
15
bis(2-ethylhexyl) phthalate
EPA 8061
16
dicyclohexyl phthalate
17
di-n-octyl phthalate
18
diisononyl phthalate
EU
19
diisodecyl phthalate
EU
20
dinonyl phthalate
EPA 8061
5.5 min
200 °C (hold 0.5min) to 330 °C (hold 1 min) @ 30 °C/min 66.7 cm/sec
EPA 8061
EPA 8061, EPA Priority,
EU
EPA 8061, EPA Priority,
EU
EPA Regulated Phthalates FREE?
 Technical grade
reference standards

Internal Standard
Synthetic byproducts
EPA Regulated Phthalates FREE?
Phthalates
Sources
Impurity 1 Name
Percentage
Impurity 2 Name
Percentage
Benzyl 2-ethylhexyl phthalate
Vendor 1
Bis(2-ethylhexyl) phthalate
1.1%
Dibenzyl phthalte
N/A
Butyl cyclohexyl phthalate
Vendor 1
Di-n-butyl phthalate
20.3%
Dicyclohexyl phthalate
16.7%
Butyl octyl phthalate
Vendor 1
Di-n-butyl phthalate
14.1%
Di-n-octyl phthalate
20.1%
Hexyl 2-ethylhexyl phthalate
Vendor 1
Di-n-hexyl phthalate
14.3%
Bis(2-ethylhexyl) phthalate
19.2%
n-Octyl-n-decyl phthalate
Vendor 1
Di-n-octyl phthalate
12.1%
Didecyl phthalate
N/A
Benzyl 2-ethylhexyl phthalate
Vendor 2
Bis(2-ethylhexyl) phthalate
18.1%
Dibenzyl phthalte
N/A
Butyl cyclohexyl phthalate
Vendor 2
Di-n-butyl phthalate
20.6%
Dicyclohexyl phthalate
7.5%
Butyl octyl phthalate
Vendor 2
Di-n-butyl phthalate
15.0%
Di-n-octyl phthalate
18.5%
Hexyl 2-ethylhexyl phthalate
Vendor 2
Di-n-hexyl phthalate
16.5%
Bis(2-ethylhexyl) phthalate
24.6%
n-Octyl-n-decyl phthalate
Vendor 2
Di-n-octyl phthalate
12.5%
Didecyl phthalate
N/A
Hexyl idodecyl phthalate
Vendor 2
Di-n-hexyl phthalate
16.1%
Diisodecyl phthalate
N/A
2-Ethylhexyl isodecyl phthalate
Vendor 2
Bis(2-ethylhexyl) phthalate
16.1%
Diisodecyl phthalate
N/A
n-Hexyl decyl phthalate
Vendor 2
Di-n-hexyl phthalate
10.8%
Didecyl phthalate
N/A
Butyl decyl phthalate
Vendor 2
Di-n-butyl phthalate
20.8%
Didecyl phthalate
N/A
Butyl 2-ethylhexyl phthalate
Vendor 2
Di-n-butyl phthalate
15.5%
Bis(2-ethylhexyl) phthalate
19.3%
Butyl isodecyl phthalate
Vendor 2
Di-n-butyl phthalate
14.2%
Diisodecyl phthalate
N/A
Technical Grade
Phthalate Interferences with
Pesticides Analysis
Phthalates?
Pesticides?
Minimizing Phthalate Interferences Using the
Rtx®-CLPesticides / Rtx®-CLPesticides2 Columns
Peak Analyte
Peak
Analye
1
2,4,5,6-Tetrachloro-m-xylene
12
4,4'-DDE
2
α-BHC
13
Dieldrin
3
γ-BHC
14
Endrin
4
β-BHC
15
4,4'-DDD
5
δ-BHC
16
Endosulfan II
6
Heptachlor
17
4,4'-DDT
7
Aldrin
18
Endrin aldehyde
8
Heptachlor epoxide (isomer B)
19
Endosulfan sulfate
9
trans-Chlordane
20
Methoxychlor
10
cis-Chlordane
21
Endrin ketone
11
Endosulfan I
22
Decachlorobiphenyl
Peak Analyte
Peak Analyte
A
Diisobutyl phthalate
J
Butyl octyl phthalate
B
Di-n-butyl phthalate
K
Butyl benzyl phthalate
C
Bis(2-methoxyethyl) phthalate
L
Hexyl 2-ethylhexyl phthalate
D
Bis(4-methyl-2-pentyl) phthalate M
Butyl isodecyl phthalate
E
Diamyl phthalate
N
Bis(2-n-butoxyethyl) phthalate
F
Bis(2-ethoxyethyl) phthalate
O
Bis(2-ethylhexyl)phthalate
G
Butyl 2-ethylhexyl phthalate
P
Dicyclohexyl phthalate
H
Butyl cyclohexyl phthalate
Q
Di-n-octyl phthalate
I
Di-n-hexyl phthalate
R
Dibenzyl phthalate
Phthalate Determination by Dual
Column Set in Eight Minutes
Phthalate Determination by Dual
Column Set in Eight Minutes
Rtx®-440
30 m × 0.25 mm × 0.25 µm
Rxi®-35Sil MS
30 m × 0.25 mm × 0.25 µm
8
min
40
min
EPA 8061A
Conclusions