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Nitrosamine Detection in Meat. By Beryl Ombaso, Chemistry 4101, Fall 2008. BACKGROUND. Nitrite is added to meat both for preservation and color enhancement. Amines in the meat react with the nitrite to form nitrosamines which are known carcinogens. 1
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Nitrosamine Detection in Meat By Beryl Ombaso, Chemistry 4101, Fall 2008
BACKGROUND • Nitrite is added to meat both for preservation and color enhancement. • Amines in the meat react with the nitrite to form nitrosamines which are known carcinogens.1 NO2 + H+ HNO2 2HNO2 N203 + H20 N203 + R2NH R2N.NO + HNO2 (a nitrosamine)
Tumorgenic levels of Nitrosamines • USDA recommended exposure level-10 ppb.2
Proposed Method for Nitrosamine Detection • Gas Chromatography with tandem MS would be most ideal.6 • Nitrosamines are highly volatile and thermally stable. • Limit of detection – 0.01 ppb. • Linear range – 0.01 to 10 ppb. • Percent recovery – 70-80 %. • Efficient separation and ease of use.
Interfering species: amines, amino acids. SPE limits amount of interfering species. Blank sample consists of 0.1N NaOH. SAMPLE PREPARATION
Experimental conditions6 • Combination of Extrelut-Florisil cartridge for SPE. • Column – 30 m, 0.25 mm i.d, 0.25 μm film thickness containing 1:6 cyanopropylphenyl:methyl polysiloxane. • Carrier gas – Helium gas at 1.0 mL/min. • Oven – initial temp. 500C, final temp. 2600C • Injection volume- 2.0 μl • Outlet pressure – 54.8 kPa • Electrospray ionization at 70eV. • Reagent for chemical ionization- ammonia gas. • Quadrupole mass selective detectors for analysis.
Sample Mass Spectrum • Quantification accomplished by using calibration curve obtained from standards. • Standards obtained easily from manufacturer.
HP 5890A/5970 GC/MS Cost: $ 9,950 Oven temp: up to 4500C Compact size Power supply: 120V Resolution: 0.1amu S/N: 20:1 Scan speed: 1500 amu/sec Mass range:10 – 800 amu Gentechscientific.com Equipment model
References 1. Mirvish, S.; Cancer letters, 1995, 93, 17-48. 2. Jay, J.; Modern Food Microbiology, 6th Ed, 2000, pg 261. 3. Perez, E. L.; Rios, A.; Valcarcel, M.; J Anal. Chem,2001, 371, 891-895. 4. Oliveira, R. T.; Salazar-Banda, G. R.; Machado, S. A.; Avaca, L. A.; Electroanalyis, 2008, 20, 396-401. • Cardenes, L.; Ayala, J. H.; Venerando, G.; Afonso, A. M.; J. Liq. Chrom. & Rel. Technol., 2002, 25, 977-984. • Jurtchenko, S.; Tenno, T.; Molder, U.; Reinik, M.; Proc. Estonian Acad. Sci. Chem., 2002, 51, 169-184.