A rapid and simple method for the simultaneous determination of twelve sweeteners and nine preservatives in various foods by liquid chromatography-tandem mass spectrometry LC-MS/MS was developed. The sweeteners and preservatives were extracted from solid samples with 80 and 50 methanol and from liquid samples with 80 methanol, followed by Oasis WAX cartridge cleanup. The LC separation was performed on a XSelect CSH Phenyl-Hexyl column 5 μm, 2.1 mm ×150 mm with a mobile phase of 10 mmol/L acetate buffer pH 4.0 -acetonitrile and MS detection with negative ion electrospray ionization. The quantification limits of acesulfame K AK , alitame AL , aspartame ASP , cyclamic acid CYC , neotame NEO , saccharin Na SAC , p-hydroxybenzoic acid methyl PHBA-Me , p-hydroxybenzoic acid ethyl PHBA-Et , p-hydroxybenzoic acid isopropyl PHBA-iPr , p-hydroxybenzoic acid propyl PHBA-Pr , p-hydroxybenzoic acid isobutyl PHBA-iBu and p-hydroxybenzoic acid butyl PHBA-Bu were 0.001 g/kg, those of dulcin DU , glycyrrhizic acid GLY , neohesperidin dihydrochalcone NHDC rebaudioside A REB , stevioside STV , sucralose SUC and benzoic acid BA were 0.005 g/kg, and those of sorbic acid SOA and dehydroacetic acid DHA were 0.02 g/kg. The mean recoveries from ten kinds of foods fortified at the levels of 0.02 and 0.2 g/kg were 70.9-119.0 , and their relative standard deviations were 0.1-11.7 .
A rapid and sensitive TaqMan real-time PCR assay for the detection of Pacific cod (Gadus macrocephalus) and capelin (Mallotus villosus) roes in Alaska pollack (Theragra chalcogramma) roe product was developed. The primers and the TaqMan MGB (minor groove binder) probes were designed based on the gene encoding cytochrome b for the specific detection of Alaska pollack, Pacific cod and capelin. This real-time PCR assay had the detection limit of 0.002 ng/ῌL mitochondrial DNA and showed no cross-reaction with 48 other species. The calculated r 2 values of the standard curves for the three species were 1.000. This assay was applied for the detection of Pacific cod and capelin roes in mixture samples: Pacific cod or capelin roes were added to Alaska pollack roes at 0.1, 1 and 10̮. The threshold cycle values were obtained from both of the mixture samples at 0.1̮. Practical applicability of this assay was examined with 64 samples of Alaska pollack roe products. In all cases, the species detected from the samples corresponded with species described on the food label.
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