1 IFIN-HH National Insitute for Physics and Nuclear Engeneering Multipurpose Irradiation Facility IRASM A Study on optimization the sample preparation for gas chromatographic methods used in routine irradiated foodstuffs detection M. Virgolici, A.V. Medvedovici, M.M. Manea, M. Cutrubinis, I.V. Moise, R.M. Georgescu International Coference on Recent Developments and Applications of Nuclear Technologies Bialowieza, Poland - 15 – 17 September 2008 - METHODS IFIN-HH Centrul de Iradieri Tehnologice IRASM 1. Using the Gas Chromatographic Microbial Identification System (MIDI, Inc.) for fatty acids profiling of extracted fat from irradiated foods. Enabling C n-1:0 and C n-2:1 hydrocarbons (HC) and 2- alkylcyclobutanones prediction virtually from any fats which contain fatty acids with chain length ranging from 9 – 20 carbon atoms in length 2. Structure confirmation of main identified fatty acids by Gas Chromatography coupled with Mass Spectrometry (GC-MS) 3. Cn-1:0 and Cn-2:1 HC detection using EN 1784 standard and optimized GC-MS method for identification of irradiated foods that contain fat 4. 2-Alkylcyclobutanones detection using EN 1785 standard and optimized GC-MS method for identification of irradiated foods that contain fat 5. Intercomparison with the ESR method for detection of irradiated foods which contain bones IFIN-HH Centrul de Iradieri Tehnologice IRASM Samples : Chicken, Salmon, Crab and Shrimp aquired from Romanian market Samples storage: in freezer before and after irradiation Gamma Irradiation : SVST Co-60 IRASM facility Irradiation dosses : 0, 2, 7 and 10 kGy Dosimetry : ECB (STDEV + 2% @ 1σ) Fatty acids profiles and identification : Sherlock 6.0 Microbial Identification System (MIDI, Inc. USA) and GC-MS performed on Agilent GC 6890N gas chromatograph with two channels: - classical split/splitless injector (S/SL) – Ultra 2 non polar capillary column – classical Flame ionisation detector (FID) for Sherlock - programable temperature vaporizer (PTV) CIS 4 (cooled injection systems) made by Gerstel with Peltier cooling to 10C – HP-5ms non polar capillary column – coupled with Agilent 5795 inert EI MSD (Mass Spectrometric Detector) for structural identification using reference substances spectra and NIST 2005 MS Library Samples and Instrumentation
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IFIN-HH National Insitute for Physics and Nuclear Engeneering
Multipurpose Irradiation Facility IRASM
A Study on optimization the sample preparation for
gas chromatographic methods used in routine
irradiated foodstuffs detection
M. Virgolici, A.V. Medvedovici, M.M. Manea, M. Cutrubinis,
I.V. Moise, R.M. Georgescu
International Coference on
Recent Developments and Applications of Nuclear Technologies
Bialowieza, Poland
- 15 – 17 September 2008 -
METHODSIFIN-HH
Centrul de Iradieri Tehnologice IRASM
1. Using the Gas Chromatographic Microbial Identification System
(MIDI, Inc.) for fatty acids profiling of extracted fat from irradiated
foods. Enabling Cn-1:0 and Cn-2:1 hydrocarbons (HC) and 2-
alkylcyclobutanones prediction virtually from any fats which contain
fatty acids with chain length ranging from 9 – 20 carbon atoms in
length
2. Structure confirmation of main identified fatty acids by Gas
Chromatography coupled with Mass Spectrometry (GC-MS)
3. Cn-1:0 and Cn-2:1 HC detection using EN 1784 standard and
optimized GC-MS method for identification of irradiated foods that
contain fat
4. 2-Alkylcyclobutanones detection using EN 1785 standard and
optimized GC-MS method for identification of irradiated foods that
contain fat
5. Intercomparison with the ESR method for detection of irradiated
foods which contain bones
IFIN-HH
Centrul de Iradieri Tehnologice IRASM
Samples : Chicken, Salmon, Crab and Shrimp aquired from Romanian market
Samples storage: in freezer before and after irradiation
Gamma Irradiation : SVST Co-60 IRASM facility
Irradiation dosses : 0, 2, 7 and 10 kGy
Dosimetry : ECB (STDEV + 2% @ 1σ)
Fatty acids profiles and identification : Sherlock 6.0 Microbial Identification
System (MIDI, Inc. USA) and GC-MS performed on Agilent GC 6890N gas
- Ultrasound fat extraction allows smaller extraction time, simple glassware, with the same volume of high purity solvents or smaller
- Direct solvent extraction method (Tewfik 2008) enables 3 times smaller solvent volumes, total reduction to sample preparation to 90 min, and the same results for 2-ACB.
Use of last two techniques could lead to comparable results in more resonabletime per sample and resonable costs.
IFIN-HH
Centrul de Iradieri Tehnologice IRASM
Detectie RES os pui
0
10000
20000
30000
40000
50000
60000
329 330 331 332 333 334 335 336 337 338 339
Camp magnetic (mT)
Inte
ns
itate
(u
.a.)
0 kGy 2 kGy 7 kGy 10 kGy
ESR method for detection of irradiated bonesDetection of irradiated Chicken
IFIN-HH
Centrul de Iradieri Tehnologice IRASM
Detectie RES os somon
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
50000
55000
329 330 331 332 333 334 335 336 337 338 339
Camp magnetic (mT)
Inte
ns
ita
te (
u.a
.)
0 kGy 2 kGy 7 kGy 10 kGy
ESR method for detection of irradiated bonesDetection of irradiated Salmon
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IFIN-HH
Centrul de Iradieri Tehnologice IRASM
Detectie RES os crab
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
329 330 331 332 333 334 335 336 337 338 339
Camp magnetic (mT)
Inte
sit
ate
(u
.a.)
0 kGy 2 kGy 7 kGy 10 kGy
ESR method for detection of irradiated bonesDetection of irradiated Crab
IFIN-HH
Centrul de Iradieri Tehnologice IRASM
Detectie RES os crevete
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
100000
329 330 331 332 333 334 335 336 337 338 339
Camp magnetic (mT)
Inte
ns
ita
te (
u.a
.)
0 kGy 2 kGy 7 kGy 10 kGy
ESR method for detection of irradiated bonesDetection of irradiated Shrimp
ConclusionsIFIN-HH
Centrul de Iradieri Tehnologice IRASM
- Fatty acid profiling using Sherlock MIS method is an efficient way of
determination fatty acid composition of various fats before HC and 2-
ACB detection enabling use of standardized methods EN 1784 and EN
1785 outside of the available validation data
- Use of PTV Cooled Injection Systems can enable detection of smaller
quantities of HC and 2-ACB comparing with classical methods
- The sensitivity improvement of HC and especially 2-ACB detection in
conjunction with more faster extraction methods will enable a larger
number of samples for routine testing, and maybe smaller costs
- ESR method for detection of irradiated foodstuffs on bone samples
can be used for intercomparison purposes with chemical methods for
detection of meat samples
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IFIN-HH
Centrul de Iradieri Tehnologice IRASM
Thank You for You Attention
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