Application Note 1010
Introduction
Headspace analysis by means of a dedicated autosampler
is a standard technique for the determination of volatile
organic compounds (VOCs) possibly present in food
packaging materials. The packaging sample is typically
cut into square pieces and placed in headspace vials
for incubation at a determined temperature before the
headspace sampling. The main challenge with this kind of
analysis is the quantification of volatile compounds that are
present because these samples are typically layered solids
that generate adsorption and migration effects. External
calibration is not reliable because it does not consider the
matrix effect, which is significant for these samples.
In contrast, the standard addition calibration is a reasonable
quantification procedure for these difficult matrixes because
it uses real sample for the calibration procedure. Until now,
preparation of samples for the standard addition calibration
has been performed off-line, typically executed manually
by the operator before headspace analysis of the samples.
This is a time-consuming and error-prone procedure, while
performing sample preparation by means of the same
robotic sampler used for headspace analysis enables the
quantification sequence to be run automatically in an
unattended way. Detection and quantification are performed
by means of a gas chromatograph (GC) coupled with a
single quadrupole mass spectrometer (MS).
Materials and Methods
Use the Thermo Scientific TRACE 1310 GC, coupled with
the ISQ Single Quadrupole GC-MS, for analysis of the
samples. Configure the GC with an instant connect split/
splitless (SSL) module, operated in split mode.
The headspace incubation temperature is 80 °C and the
incubation time is 15 min. The headspace injected volume
is 1 mL. Use the Thermo Scientific TraceGOLD TG-624
GC Column (1.4 µm film thickness; 0.25mm ID; 60m
length).
The VOCs standards solution is:
• Residual Solvents in Packaging Material Mixture 1,
analytical standard, 7.14% (v/v) (Sigma-Aldrich
®
)
• Residual Solvents in Packaging Material Mixture 2,
analytical standard, 9.09% (v/v) (Sigma-Aldrich)
Mix to obtain a single comprehensive stock solution.
Automatically perform subsequent sample preparation
and injection steps using the Thermo Scientific TriPlus
RSH Autosampler. The tool exchange capability and
vortex mixing allow the dilution step, the standard
addition step, and the headspace analysis step to be
combined together in the same sequence.
Procedures
Automatic Standard Dilution Procedure
The stock solution is first automatically diluted 1/1000
with water by the TriPlus™ RSH autosampler. In this
cycle, the autosampler takes the necessary aliquot of
water and places it in an empty vial, adding the amount of
stock solution to bring to final volume (in this case, 1 ml)
using a different volume syringe.
The diluted solution obtained contains all the components
in a concentration range of 0.035–0.045 µg/µL that is
suitable for the determination of low levels of residual
solvent in packaging material.
Unattended Automated Standard
Addition and Headspace Analysis
for the Quantitative Determination
of VOCs in Food Packaging
Stefano Pelagatti,
1
Silvia Gemme,
1
Andrea Caruso,
1
Fausto Pigozzo,
1
Massimo Santoro,
1
and Eric Phillips
2
1
Thermo Fisher Scientific, Milan, Italy;
2
Thermo Fisher Scientific, Austin, Texas, USA
Key Words
TRACE 1310 GC, ISQ GC-MS, TriPlus RSH,
Volatile Organic Compounds in Food Packaging
Goal
To demonstrate fully automated quantitative determination
of volatile components in food packaging
