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 .

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A method for the determination of nonvolatile amines (putrescine, cadaverine, histamine, tyramine and spermidine) in foods by solid-phase extraction and excimer-forming derivatization was investigated. Nonvolatile amines in a solid sample were extracted with 3 trichloroacetic acid, and the amines in a liquid sample were extracted with water. The extract was applied to polymer-based strong cation exchange mini-column, which was then rinsed with phosphate bu#er of pH 6.8 and water. Nonvolatile amines were eluted with 100 mmol/L potassium carbonate solution. The solution was mixed with 6 mmol/L 1-pyrenebutylyl chloride solution and derivatized. Derivatives of nonvolatile amines were analyzed by LC-FLD, and the identity of the amines was confirmed by LC-MS/MS without derivatization. The limit of detection (S/Nΐ3) of nonvolatile amines in all samples was 0.04 ῌg/g, and the limit of quantitation (S/Nΐ10) was 0.1 ῌg/ g. Recoveries of nonvolatile amines from fish tissues, miso, shoyu and red wine were in the range of 80.4ῌ111.

A simple and rapid method was developed for the analysis of mepiquat chloride in grape, wine and juice by high-performance liquid chromatography with electrospray tandem mass spectrometry (LC/MS/MS). Mepiquat chloride was extracted with waterῌmethanol (1 : 1). Extracted solution was adjusted to pH 10 with ammonia solution. A part of the extracted solution was cleaned up on a styrenedivinylbenzene (SDVB) cartridge for LC/MS/MS. The LC separation was performed on a C18 column (50 mmΐ2 mm i.d.) using 0.1 IPCC-MS7ῌmethanol (60 : 40) as the mobile phase at a flow rate of 0.2 mL/min. The mass spectral acquisition was done in the positive ion mode by applying selected reaction monitoring (SRM). The recoveries of mepiquat chloride from fresh grape, wine and juice fortified at 5 mg/kg and 50 mg/kg were 84.5ῌ96.1. The lower limit of quantification was 1 mg/kg. Fourteen fresh grape samples, 14 wines (white), 36 wines (red) and 11 juice samples were analyzed by this method. Mepiquat chloride was detected in 5 fresh grape samples, 3 wines (white) and 1 wine (red) at the level of 12.8ῌ199 mg/kg, 5.7ῌ47.7 mg/kg and 24.1 mg/kg, respectively.