GC Analysis of Volatiles in Milk (Before and After Exposure to Sunlight) on Supel-Q™ PLOT after SPME using a 75 μm PDMS/Carboxen Fiber

GC Analysis of Volatiles in Milk (Before and After Exposure to Sunlight) on Supel-Q™ PLOT after SPME using a 75 μm PDMS/Carboxen Fiber

Conditions

sample/matrix 3 g of 2% milk + 10 µl internal standard solution (20 µg/mL 4-methyl-2-pentanone) (9 mL GC vial)
desorption process 5 min, 250 C
extraction headspace, 15 min with constant stirring at 45 C
SPME fiber PDMS/Carboxen, 75 µm (57318)
column Supel-Q PLOT, 30 m x 0.32 mm I.D. (24242)
oven 70 C (2 min) to 140 C at 6 C/min (2 min hold) then to 220 C at 6 C/min (5 min hold)
carrier gas helium, 35 cm/sec
sample Milk
injection splitless, closed 2 min
liner 0.75 mm liner
inj. temp. 250 C
detector GC-MS ion trap, m/z = 33-300

Description

Analysis Note In this study, SPME was used for the analysis of volatiles in milk using a headspace method. Light can catalyze the formation of peroxides that can cleave double bonds in fatty acids. The cleaved by-products form aldehydes that can give the food a pungent off flavor. Dr. Ray Marsili investigated the feasibility of using SPME as a substitute sample preparation device prior to GC/MS analysis. The Carboxen/PDMS fiber was evaluated for the extraction of low ppb levels of pentanal, hexanal, and dimethyldisulfide. The results of the comparison of SPME to dynamic headspace analysis indicate that SPME-GC/MS is more accurate and precise while providing sensitivities equivalent to DH-GC/MS. The GC column used, Supel-Q PLOT, operates via gas-solid chromatography with a DVB adsorbent and permits the separation of a wide range of analytes.
Categories Analytical Chromatography, Food & Beverage Analysis, SPME Applications, GC Applications, Foods, Flavors & Fragrances, Beverage Testing, Milk, Volatiles
Featured Industry Food and Beverages
Legal Information Supel-Q is a trademark of Sigma-Aldrich Co. LLC
Other Notes Complementary products:
Syringes
Vials
Gas Purification and Gas Management
Inlet Liners, Glass Wool, and Specialized Hand Tools
Septa and Specialized Hand Tools
Column Ferrules, Nuts, and Specialized Hand Tools
suitability application for SPME, application for GC

Analyte

  • 2-Butanone
  • 3-Methylpentane
  • Acetone
  • Dimethyl disulfide
  • Hexanal
  • Pentanal

Materials

     
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