The Consumer Product Safety Improvement Act of 2008 (CPSIA-USA) requires testing of child care products and toys in the US for specific phthalate esters by GCMS. The CPSC test method specifies solvent extraction and subsequent GCMS analysis for specific phthalate esters. In this study, analysis by pyrolysis GCMS was investigated as a technique to simplify sample preparation and improve analytical precision.

1. Evaluation of Sample Pretreatment Procedures for the
Determination of Phthalate Esters in Child Care
Products and Children’s Toys by Gas Chromatography
/ Mass Spectrometry (GCMS)
Richard Whitney, PhD, Nicole Lock, Jiarui “Jerry” Wang, Zhuangzhi
“Max” Wang, PhD, Clifford M. Taylor, Laura Chambers, Shimadzu
Scientific Instruments, Columbia, MD, USA, 800-477-1227,
www.ssi.shimadzu.com

2. Introduction (1)
The Consumer Product Safety Improvement Act of 2008 (CPSIA-USA) requires testing of child care
products and toys in the US for specific phthalate esters by GCMS. The CPSC test method specifies
solvent extraction and subsequent GCMS analysis for specific phthalate esters. In this study, analysis by
pyrolysis GCMS was investigated as a technique to simplify sample preparation and improve analytical
precision. The analyses were conducted on a Shimadzu GCMS-QP2010 Ultra equipped with a Frontier PY-
2020is pyrolyzer, shown in the figure below.
The CPSC test method also specifies GCMS analysis in the SIM mode to monitor for low-intensity ions that
are unique to specific phthalate esters. Full-scan mass spectra are extremely valuable in making
unequivocal qualitative identification of specific phthalate isomers, however. Operation of the mass
spectrometer in the FASST (Scan/SIM) mode allows concurrent acquisition of full-scan and SIM mass
spectral data, without sacrificing sensitivity of SIM analysis.
Significant interferences, particularly terephthalate esters, are frequently present in real-world samples. An
alternate chromatographic column (RXI-17Sil MS) provides excellent chromatographic resolution of bis(2-
ethylhexyl) terephthalate, a common interference, from the regulated phthalate esters.
Acceptable method performance is achieved for calibration and control samples, but difficulties have been
encountered in obtaining reproducible results for real-world samples using the sample extraction procedure
in the CPSC method. Using the sample extraction procedure, analyses of replicate aliquots (50mg of
polymer) of a sample known to contain target phthalate esters were conducted to evaluate method
reproducibility. Results indicate that instrument precision is good; variability in results was previously
assumed to be related to inhomogeneity of the polymer.

3. Introduction (2)
Pyrolysis at relatively low temperature (“thermal extraction”) was investigated as a sample introduction
technique; pyrolysis offers the advantage of eliminating the time-consuming sample pretreatment
procedure. It was anticipated that smaller (1mg) aliquots may show even more disparity in results than
those observed with liquid extraction because sample homogeneity may be accentuated. However,
improved precision was observed with replicate samples analyzed using pyrolysis relative to that obtained
from replicate extractions. To further evaluate the effect of polymer homogeneity on the analytical precision,
the sample was homogenized by cryogenic milling. Replicate analyses of the homogenized sample showed
further improved precision relative to pyrolysis of the intact sample.
Frontier PY-2020is Shimadzu GCMS-QP2010 Ultra

4. Analytical Conditions
GC Conditions
The GC is operated in the splitless
mode, using a RXI-5MS 30M x 0.25mm
x 0.25µ capillary column (Restek), as
specified by the CPSC method.
Analysis using a RXI-17Sil MS 30M x
0.25mm x 0.25µ capillary column
(Restek) is conducted using the same
chromatographic conditions.
MS Conditions
The MS is operated in the EI
Scan/SIM (“FASST”) mode, to
provide optimum sensitivity while still
providing full-scan mass spectra for
unequivocal qualitative identification.
4

5. Chromatography of Phthalate Esters
RXI-5MS Column 30M x 0.25mm x
0.25µ (Restek Corp) Diisononyl phthalate and diisodecyl phthalate appear
as multiple chromatographic peaks
1 - Benzyl Benzoate (IS)
2 - Dibutyl Phthalate
6 3 - Butyl Benzyl Phthalate
4 - Diethylhexyl Phthalate
4 5 - Di-n-octyl Phthalate
5
6 - Diisononyl Phthalate
3 7 7 - Diisodecyl Phthalate
1 2
5

6. Chromatographic Interferences
Interference from non-regulated phthalate esters and related compounds
masks trace detection of the regulated phthalate esters.
Noteworthy is interference of bis(2-ethylhexyl) terephthalate (a commonly-
used, non-regulated plasticizer) with detection of di-n-octyl phthalate; these
compounds coelute on the RXI-5MS column and have key mass spectral
fragment ions in common (m/z 149, 167, 279).
Example of chromatography of Full-scan mass spectra are extremely
equal concentrations of di-n-octyl useful in qualitative identification. SIM
phthalate and bis(2-ethylhexyl) data alone would make qualitative
terephthalate. identification difficult in these cases.
di-n-octyl phthalate bis(2-ethylhexyl) terephthalate

7. Chromatography on RXI-17Sil MS Column
Bis(2-ethylhexyl) terephthalate (“DOTP”) is well-resolved from the regulated
phthalate esters on an RXI-17Sil MS 30M x 0.25mm x 0.25µ capillary column
(Restek), using the same chromatographic conditions as with the RXI-5MS column.
(Elution of butyl benzyl phthalate is somewhat later than on the RXI-5MS column.)
1 - Benzyl Benzoate (IS)
2 - Dibutyl Phthalate
3 - Butyl Benzyl Phthalate
4 - Diethylhexyl Phthalate
5 - Di-n-octyl Phthalate
DOTP interference is well-resolved from the 6 - Diisononyl Phthalate
regulated phthalate esters 7 - Diisodecyl Phthalate
6
1
2 4 3 5
7
7

8. Basic Method Performance
Fundamental method performance is satisfactory:
• Good chromatography, with excellent linearity and precision for
analytical standards and QC samples
• Excellent sensitivity with FASST (Scan/SIM)
Issues with method implementation:
• Background contamination with phthalate esters from various
sources – method blanks are very critical.
• Interferences from non-regulated phthalate esters and related
compounds – chromatographic and mass spectral interferences with
detection and quantitation of regulated phthalate esters.
• Disparate analytical results have been obtained in several
laboratories. The cause of this disparity was previously assumed to
be variable homogeneity of solid samples.

9. Sample Preparation Scheme for Replicate
Analyses of Intact Vinyl Film Sample
9

10. Summary of Replicate Results for
Extracted Aliquots
Diethylhexyl phthalate Observations / Conclusions
600
Std Dev
(concentration)
Graphical representation of the results show instrument
400 precision (Std Dev, shown by the dark blue bars in the
200 graphic) is considerably better than precision between
Diethylhexyl
0 Phthalate aliquots.
1 2 3 4 Concentration
(mg/Kg)
Results for dibutyl phthalate and butyl benzyl phthalate
Diisononyl phthalate are very low (single digit precision), so results for these
Std Dev
800 (concentration) analytes are not shown here.
600
400
200 Diisononyl The sample preparation for these analyses was
Phthalate
0
Concentration
conducted simultaneously by the same analyst, so
1 2 3 4
(mg/Kg) sample preparation technique was not assumed to be the
source of disparity of the results
Diisodecyl phthalate
1200.0
Std Dev
(concentration) These results indicate that disparity in results of replicate
1000.0
800.0 sample analysis are related to sampling (sample
600.0
400.0
homogeneity) or sample preparation, not poor precision
Diisodecyl
200.0
Phthalate and accuracy in the instrumental analysis.
0.0
Concentration
1 2 3 4
(mg/Kg)

11. Solutions for CPSC Method Performance
Issues
CPSC Method Performance Issue Solution
Difficulties in qualitative identification Conduct analyses using Scan/SIM
of regulated phthalate esters with function (FASST) for unequivocal
SIM data. qualitative identification.
Low level detection of some analytes Excellent sensitivity is achieved using
difficult due to low relative Scan/SIM function (FASST), even for
abundance of quantitation ions and analytes with multiple chromatographic
multiple chromatographic peaks. peaks (DINP,DIDP).
Monitoring of low abundance ions for Use of a convenient software feature to
quantitation gives rise to large monitor ion abundance ratios allows
variations in relative abundance easy modification of method
ratios parameters
Chromatographic and spectral One major interfering compound is
interferences are encountered from easily resolved by using an RXI-17Sil
non-regulated phthalate esters and MS chromatographic column (Restek).
terephthalate esters.
Disparate results are frequently Results indicate that difficulties are
obtained for analysis of replicate related to sampling/extraction rather
analyses of solid samples. than analysis. Sample homogenization
and analysis of replicate sample
aliquots is highly recommended.
11

12. Sample Introduction by Pyrolysis
• Sample introduction by low-temperature pyrolysis (“thermal extraction”) was
investigated for applicability to this method (pyrolysis is not currently
authorized by the CPSC Method):
• Pyrolysis has the advantage of greatly simplifying sample pretreatment –
significant time savings.
• Pyrolysis has traditionally not been considered an accurate quantitative
technique.
• Pyrolysis conditions were chosen to thermally desorb the phthalate esters
while not decomposing the polymer itself.
• Conditions for Pyrolysis GCMS (Pyr-GCMS) are similar to those used for
analysis of polymer extracts:
• Pyrolyzer temperature 325oC; interface temperature 320oC. Sample
aliquots (0.4mg) were thermally desorbed for 1.0 min.
• A 60M RXI-17Sil MS column was used to optimize separation; the split
injection mode was used to optimize sample transfer from the pyrolyzer to
the GC; additional sample was added to maintain detection limit.
12 • A single SIM group was monitored to simplify data display.

13. Polymer Sampling for Pyrolysis
Two procedures were used in sampling of the vinyl sheet sample for pyrolysis GCMS
analysis; 0.4mg sample aliquots were used for pyrolysis GS analysis:
1. Small circular aliquots of the sample were punched out of the sample directly.
2. The sample was cryogenically milled to a fine mesh and an aliquot was taken for
analysis.
Aliquots were punched from The sample was cryogenically
the vinyl sheet at various milled, resulting in a fine
positions powder.
0.4mg sample aliquots were taken from the
cryogenically milled sample. (Sample cup is
13 also shown.)

14. Calibration Using PYR-GCMS
• A six-point internal standard calibration was conducted from 0.25-
20ppm. This calibration range corresponds to the same sample
concentration of phthalate esters in the polymer as with the CPSC
(solvent extraction) method.
• Linearity was R2>0.99 for all of the analytes in both the full-scan and
SIM modes.
• Example calibration curves are shown below for diisononyl phthalate
and diisodecyl phthalate.
Area Ratio(x0.1) Area Ratio(x0.1)
5.0
Diisononyl Phthalate 3.0
Diisodecyl Phthalate
4.0
2.5
3.0 2.0
1.5
2.0
1.0
1.0
0.5
14 0.0 0.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 Conc. Ratio 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Conc. Ratio

15. Precision of Analytical Standards Results using
PYR-GCMS
Replicate analyses for eight runs of analytical standard using
PYR-GCMS show excellent instrumental precision with sample
introduction by pyrolysis (equivalent precision to liquid injection).
Mass chromatograms of Precision for analysis of 8 replicates
diisodecyl phthalate for %RSD %RSD
analysis of 8 replicates
(x10,000)
Compound Name Scan SIM
1.1
Dibutyl Phthalate 7.07 5.72
1.0
0.9
0.8
Benzyl Butyl Phthalate 7.42 7.65
0.7
0.6 Diethylhexyl phthalate 5.13 5.04
0.5
0.4
0.3
Di-n-octyl phthalate 4.40 4.88
0.2
0.1
Diisononyl Phthalate 4.12 4.82
13.00 13.25 13.50 13.75 14.00 14.25 14.50 14.75 15.00 15.25
Diisodecyl Phthalate 6.67 6.13
15

16. Precision of Real-world Sample Results using PYR-
GCMS
Replicate injections for eighteen runs of vinyl polymer sample show
reasonable instrumental precision with sample introduction by pyrolysis.
Precision is improved significantly by homogenization of the sample.
Precision for analysis of 18 replicates of vinyl polymer by PYR-GCMS
Compound Results for Intact Sample Results for Cryo-milled Sample
Mean (mg/Kg) RSD(%) Mean (mg/Kg) RSD(%)
Dibutyl Phthalate 10 34 11 11
Diethylhexyl Phthalate 44 32 311* 14
Diisononyl Phthalate 600 43 501 11
Diisodecyl Phthalate 65 35 60 15
*Disparity in results for diethylhexyl phthalate is attributed to
possible contamination during sample transport or cryo-milling.
16

17. Summary
The CPSC test method has been demonstrated using Shimadzu GCMS-
QP2010S and GCMS-QP2010 Ultra operated in the FASST (Scan/SIM)
mode. Acceptable basic method performance was demonstrated: excellent
sensitivity, linearity, and precision at low concentrations were attained.
Interferences from terephthalate esters (non-regulated compounds with
similar structures) have been encountered in real-world samples. An alternate
chromatographic column (RXI-17Sil MS) was employed to provide
chromatographic resolution of the interferences from the target phthalate
esters.
Disparate results have been observed for replicate analyses of real-world
solid samples. To cast light on this issue, replicate aliquots of a vinyl film
sample were prepared according to the CPSC method and analyzed six times
each. Replicate analyses of each aliquot showed good statistical
agreement, but disparate results were obtained for each of the sample
aliquots. These results originally suggested that disparity in the results can be
attributed to homogeneity of solid samples or irregularities in the sample
extraction process.

18. Sample introduction using pyrolysis was demonstrated to be a convenient and
reliable analytical procedure for determination of phthalate esters in a vinyl
film sample. Excellent linearity and precision for analytical standards and QC
samples were obtained using pyrolysis for sample introduction. Variable
results were observed for analysis of 0.4mg aliquots punched from the vinyl
film sample, but statistical agreement was better using pyrolysis on the intact
sample than that from analysis of replicate extraction aliquots using the CPSC
method.
The vinyl film sample was homogenized using cryogenic milling, resulting in a
fine powder. It was anticipated that the homogeneous sample would give
more precise analytical results. Indeed, analytical precision was improved
considerably using the homogenized sample.