同位素稀释-气相色谱-串联质谱法快速测定糕点类食品中邻苯二甲酸酯

建立同位素稀释-气相色谱-串联质谱法快速测定糕点类食品中27 种邻苯二甲酸酯残留量的方法。样品经正己烷-乙酸乙酯（1∶1，V/V）超声提取、十八烷基硅烷键合硅胶（C18）净化后，经程序升温气化进样口不分流进样，利用气相色谱-串联质谱法在选择反应监测模式下进行检测，采用同位素内标法定量。结果表明：27 种邻苯二甲酸酯的线性范围除邻苯二甲酸二正辛酯、邻苯二甲酸二异壬酯、邻苯二甲酸二异癸酯和邻苯二甲酸二月桂酯为0.1～20 mg/L外，其余均为0.05～10 mg/L，相关系数（r）均大于0.99。方法检出限范围为0.000 1～0.009 8 mg/kg，方法定量限范围为0.000 5～0.032 6 mg/kg。在20 种不同糕点基质中3 个添加水平（0.1、0.2、2.0 mg/kg）的平均回收率为74.3%～117.5%，相对标准偏差为2.9%～13.5%。该方法前处理简单快速、灵敏度高、测定线性范围宽，适用于糕点类食品中邻苯二甲酸酯残留量的检测与确证。

Determination of Phthalate Esters in Pastry by Isotope Dilution Gas Chromatography-Tandem Mass Spectrometry

An isotope dilution gas chromatography-tandem mass spectrometry (GC-MS/MS) method was applied to determine 27 phthalate ester residues in pastry. Samples were extracted with a mixture of n-hexane and ethyl acetate (1:1, V/V) and the extract was cleaned up on a C18 column, detected by GC-MS/MS under multiple-reaction monitoring (MRM) mode, and quantified by an isotope internal standard method. The calibration curves of 23 out of 27 phthalate esters tested showed good linearity in the range of 0.05–10 mg/L, while those of di-n-octyl phthalate (DNOP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP) and phthalic acid, bis-dodecyl ester (DLP) were highly linear in the range of 0.1–20 mg/L, all with correlation coefficients greater than 0.99. The limits of detection (LODs) were in the range of 0.000 1–0.009 8 mg/kg and the limits of quantification (LOQs) ranged from 0.000 5–0.032 6 mg/kg. The recoveries of the proposed method for 20 different pastries at spiked levels of 0.1, 0.2 and 2.0 mg/kg were 74.3%–117.5% with relative standard deviations (RSDs) of 2.9%–13.5%. The method is simple and sensitive with a wide linear range, and can be suitable for the determination of phthalate ester residues in pastry.