QuEChERS-GC-MS联用法检测大麦中14种邻苯二甲酸酯类塑化剂及基质效应的影响

采用QuEChERS结合气相色谱-质谱联用技术建立检测大麦中14种邻苯二甲酸酯类(phthalate esters,PAEs)塑化剂的高效、准确方法。样品粉碎、过80目筛,溶于p H 2的水溶液。采用乙腈提取,无水硫酸镁和氯化钠盐析,经十八烷基键合硅胶(C_(18))净化,C_(18)/大麦比例为50 mg/g;以提取后添加法对大麦中PAEs检测的基质效应评估。结果表明,大麦基质对PAEs均存在基质增强效应,增强比为41.0%~78.1%,采用基质匹配-标准曲线法能较好消除基质效应的影响,提高定量准确度;14种PAEs在大麦基质3个加标水平(15、150μg/kg和500μg/kg)的平均回收率为73.8%~120.1%,相对标准偏差均小于10%;检出限(3倍)与定量限(10倍)分别为0.1~2.5μg/kg和0.13~5.0μg/kg。应用该方法对6个不同产地的大麦原料检测,结果显示:邻苯二甲酸二甲酯、邻苯二甲酸二乙酯、邻苯二甲酸二异丁酯、邻苯二甲酸二丁酯(dibutyl phthalate,DBP)和邻苯二甲酸二(2-乙基)己酯(bis(2-ethylhexyl)phthalate,DEHP)在6个样品中均有检出,含量存在差异;参照GB 9685—2008《食品容器、包装材料用添加剂使用卫生标准》规定,本次检出的大麦样品中DBP、DEHP含量均低于允许最大残留限量标准。

Validation of a QuEChERS-based Gas Chromatography-Mass Spectrometry Method for Analysis of 14 Phthalate Esters in Barley with Focus on Matrix Effects

A modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method was developed for the extraction of 14 phthalate esters (PAEs) in barley prior to gas chromatography-mass spectrometry (GC-MS) analysis. All barley samples were smashed, sieved with an 80-mesh siever and dissolved in an aqueous solution at pH 2. The PAEs in samples were extracted with acetonitrile and salted out with anhydrous MgSO4 and NaCl. Then, after centrifugation, the supernatant was cleaned up with a C18 sorbent at a solid-to-liquid ratio of 50 mg/g. Moreover, the addition after extraction method was used to evaluate the matrix effects (ME) in the GC-MS analysis of 14 PAEs. As a result, all 14 PAEs exhibited an enhanced matrix effect in barley matrix, with a percentage enhancement in the range of 41.0% to 78.1%. Thus, a matrix-matched curve could be used to eliminate the matrix effects and in turn achieve more accurate quantitation. The recoveries of 14 PAEs in barley matrixes at three spiked levels of 15, 150 and 500 μg/kg ranged from 73.8% to 120.1% with relative standard deviations (RSD) below 10%. The limits of detection (LODs) and limits of quantitation (LOQs) for the PAEs, based on RSN ratio of 3 and 10, ranged from 0.1 to 2.5 μg/kg and from 0.13 to 5.0 μg/kg, respectively. Finally, the 14 PAEs in six barley samples were successfully determined using the proposed method. The results indicated that dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DIBP), dibutyl phthalate (DBP), and bis(2-methoxyethyl) phthalate (DEHP) were present in all the samples examined, but their concentrations were different. The contents of DEP and DEHP detected in all the barley samples were below the maximum residue limit stipulated in the Chinese National Standard (GB 9685—2008).