Nitrosamine Detection in Meat

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Nitrosamine Detection in Meat

• By Beryl Ombaso,
• Chemistry 4101,
• Fall 2008

2
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)

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Tumorgenic levels of Nitrosamines
Nitrosamine TD50, mg/kg body weight/day Expected levels in typical sample, µg/kg
Nitrosodimethylamine 0.01 1.90 2.37
Nitrosodiethylamine 0.11 0.33 0.54
Nitrosopyrrolidine 2.10 2.32 8.94
Nitrosopiperidine 1.30 0.5 1.31
Nitrosodibutylamine 0.69 0.16 0.24

• USDA recommended exposure level-10 ppb.2

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Methods for Nitrosamine detection
Method Limit of Detection Linear range Special notes
Spectrophotometry3 0.78ppb 25 to 2000 ppb Derivatization with Griess reagent.
Electroanalysis4 6.0 x 10-8 mol L-1 2 x 10-6 to 1.35 x 10-5 mol L-1 Determine total nitrosamines
HPLC/Fluorescence5 0.04 ppb 0.04 to 1.05 ppb. Derivatization with Dansyl chloride.
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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.

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Instrumentation
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SAMPLE PREPARATION

• Interfering species amines, amino acids.
• SPE limits amount of interfering species.
• Blank sample consists of 0.1N NaOH.

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Experimental conditions6

• Combination of Extrelut-Florisil cartridge for
  SPE.
• Column 30 m, 0.25 mm i.d, 0.25 µm film
  thickness containing 16 cyanopropylphenylmethyl
  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.

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Sample Chromatogram
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Sample Mass Spectrum

• Quantification accomplished by using calibration
  curve obtained from standards.
• Standards obtained easily from manufacturer.

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Equipment model

• HP 5890A/5970 GC/MS
• Cost 9,950
• Oven temp up to 4500C
• Compact size
• Power supply 120V
• Resolution 0.1amu
• S/N 201
• Scan speed 1500 amu/sec
• Mass range10 800 amu
• Gentechscientific.com

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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.