气相色谱-串联质谱法测定婴儿奶粉中16种邻苯二甲酸酯类化合物

建立了气相色谱-串联质谱（GC-MS/MS）测定复杂基体婴儿奶粉中16种邻苯二甲酸酯类塑化剂的分析方法。奶粉样品以水溶解均质，乙腈提取，乙二胺-N-丙基硅烷（PSA）类型玻璃固相萃取柱净化，DB-5 MS UI气相色谱柱（30 m×0.25 mm×0.25 μm）分离，同位素稀释质谱法（IDMS）定量。比较了氧化铝/PSA和PSA两种固相萃取柱在不同洗脱条件下萃取16种塑化剂的回收率。最终选择PSA固相萃取柱，以正己烷-丙酮（60：40，v/v）作为洗脱溶剂，实现奶粉基体中16种塑化剂的净化。采用基质匹配同位素内标法定量，16种塑化剂在0.01~2.0 mg/kg范围内线性良好，线性相关系数（R²）大于0.9996，检出限和定量限分别是0.15~2.50 μg/kg和0.50~8.33 μg/kg，加标回收率为96.1%~104.0%，相对标准偏差（RSD）小于3.3%（n=5），该方法灵敏度好、精密度高，适用于婴儿奶粉基体中16种塑化剂的痕量分析。

Determination of 16 phthalate acid esters in infant formula by gas chromatography-tandem mass spectrometry

A method was established for the determination of 16 phthalate acid esters (PAEs) in infant formula by gas chromatography-tandem mass spectrometry (GC-MS/MS). PAEs in infant formula samples were homogenized by deionized water, extracted with acetonitrile, and purified by a solid-phase extraction (SPE) method using primary secondary amine (PSA) sorbents. The separation was performed on a DB-5 MS UI (30 m×0.25 mm×0.25 μm) capillary column. Effects of different elution solvents on alumina/PSA and PSA SPE columns were investigated. Fair recoveries of 16 PAEs were achieved on the PSA column upon elution by mixed n-hexane-acetone (60:40, v/v). All the 16 PAEs were quantified by matrix-matched isotopic-dilution mass spectrometry (IDMS); the 16 PAEs showed linear relationships in the concentration range of 0.01-2.0 mg/kg with linear coefficients (R²) greater than 0.9996. The limits of detection (LODs) and quantification (LOQs) were in the range of 0.15-2.5 μg/kg and 0.50-8.33 μg/kg, respectively. The recoveries of the 16 PAEs, obtained using the IDMS method, were 96.1%-104.0% with relative standard deviations (RSDs) lower than 3.3% (n=5). These results established the method described here as sensitive and precise for the simultaneous determination of 16 PAEs in infant formula, even at trace concentrations.