High Efficiency, Quantitative Dioxins Screening
at the Level of Interest in Feed and Food using
Advanced GC-MS/MS
Paul Silcock, Dirk Krumwiede, Inge de Dobbeleer, Hans-Joachim Huebschmann,
Thermo Scientific POPs Centre of Excellence, Bremen, Germany
Alexander Kotz, CVUA Freiburg, European Union Reference Laboratory for Dioxins and PCBs in Feed and Food, Germany
Introduction
Removing the frequency of contamination events caused
by dioxins and dioxin like substances is a high priority
for governments and organizations charged with the task
of protecting human health. The largest source of human
dioxin exposure comes though dietary intake of food of
animal origin. Consequently, there are extensive monitoring
programs in place to identify potential contamination
entering into the food chain.
1
When contamination is discovered at non-compliant
levels (above maximum levels allowed) the consequences
can be serious and widespread. Apart from the risk to
human health, contamination events can have a huge
economic and political impact and receive a very high
level of media attention. As this is the case, there is a
strong need for organizations that interact with the food
chain, from food ingredient and feed manufacturers,
through to consumer suppliers and regulatory bodies to
more closely monitor their own interest. The result is
that the testing requirement is growing, as is the burden
on confirmatory analysis capacity using high resolution
(GC-HRMS) techniques.
Current European Union regulations permit the use of
GC-MS/MS and bioassay techniques for screening dioxins
and dioxin-like PCBs at the level of interest in feed and
food samples.
2
GC coupled with triple quadrupole MS is
particularly suitable screening technique as isotope dilution
is retained as well as the high selectivity of the MS/MS
experiment. If results are determined to be at a significant
level (non compliant) then confirmatory analysis by a high
resolution technique that meets the regulatory requirement
must be carried out. In order for a screening technique to
be suitable for regulatory dioxins analysis, it must comply
with the specific regulations for screening methods and
carry with it the ability to strongly correlate with the current
“gold standard” confirmatory technique in analytical
performance and quality control. These minimum require-
ments for Total-TEQ (toxic equivalent quotient) from the
aforementioned regulations are given in Table 1.
This application note describes the use of the Thermo
Scientific TSQ Quantum XLS Ultra GC-MS/MS as applied
to high efficiency screening of PCDDs/PCDFs in feed
and food samples at the levels of interest and the level of
agreement with “gold standard” confirmatory analysis
using GC-HRMS (Thermo Scientific DFS).
Materials and Methods
Extraction and Clean-up
The extraction and clean-up process for food and feed
samples was performed according Figure 1. For food
samples with legal limits on fat basis, the application of a
maximum of 3 g of fat for clean-up is applied for achieving
low limits of quantification with this method.
GC-MS measurement
The GC-MS/MS measurements were performed using a
TSQ Quantum XLS Ultra
™
GC-MS/MS system.
The following MS/MS settings were applied:
Key Words
• Compliance
• Confirmation
• Dioxins
• GC-MS/MS
• PCBs
• Screening
Application
Note: 52266
Screening Methods Confirmatory Methods
False Negative Rate
<1%
–
Trueness
–
-20% to +20%
Precision (RSDR)
<30%
<15%
Table 1: Commission Regulation (EC) No 152/2009 (Feed), No 1883/2006 (Food)
Source Temperature
250 °C
Ionization
EI
Electron Energy
40 eV
Emission Current
50 µA
Q2 Gas Pressure (Argon)
1.5 mTorr
Collision Energy
22 V
Q1 Peak Width
0.7 amu
Q3 Peak Width
0.7 amu
Table 2: Mass spectrometer parameters
Figure 1: Extraction and clean-up for determination of PCDD/Fs and PCBs in
food and feed samples
