Determination of epoxidized soybean oil by gas chromatography/single quadrupole and tandem mass spectrometry stable isotope dilution assay.
PVC lids of glass jars often contain epoxidized soybean oil (ESBO), able to migrate and contaminate food. To establish a stable isotope dilution assay (SIDA), the 13C18-labelled internal standard ethyl 9,10,12,13-diepoxyoctadecanoate (13C(18:2E)Et) was synthesized, providing after sample preparation the same retention time as methyl 9,10,12,13-diepoxyoctadecanoate ((18:2E)Me), commonly used as a marker for ESBO in gas chromatographic (GC) analysis. For eleven different food matrices, the GC capillary columns VF-17ms, DB1701 and DB1 were tested with single quadrupole (GC/MS) as well as tandem mass spectrometric detection (GC/MS/MS). Overall, the VF-17ms column coupled with MS/MS detection showed the best results in terms of separation and sensitivity. The method validation for the matrix spiked olive oil resulted in a limit of detection (LOD) of 5 mg kg-1, a limit of quantification (LOQ) of 11 mg kg-1, a mean recovery (n=5, c=106.5 mg kg-1) of 99.7+/-5.5%, with a repeatability (within-run precision) of 6.0%. By means of GC/MS an LOQ of 21 mg kg-1 and a mean recovery (n=5, c=106.5 mg kg-1) of 103.3+/-0.8% with a repeatability of 0.9% were determined.
Rothenbacher
Thorsten
T
Chemisches und Veterinäruntersuchungsamt Stuttgart, Schaflandstrasse 3/2, 70736 Fellbach, Germany.
Schwack
Wolfgang
W
D002247:Carbon Isotopes / Q000032:analysis; D004852:Epoxy Compounds / Q000737:chemistry; D005506:Food Contamination / Q000032:analysis*; D018857:Food Packaging; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007201:Indicator Dilution Techniques; D007553:Isotope Labeling; D012680:Sensitivity and Specificity; D013024:Soybean Oil / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
D002247:Carbon Isotopes; D004852:Epoxy Compounds; D013024:Soybean Oil