气相色谱-质谱法测定食品中反式脂肪酸

The trans-fatty acid in foods was determined by GC/MS. The cis-fatty and trans-fatty acids were derivatised as methyl esters using KOH-CH₃OH. The mass fragmentation rule and chromatographic retention time rule of the methyl esters were studied. They were identified with retention time and mass characteristic ions. The method has been applied to determine trans-fatty acid in foods.     

脂肪醇聚氧乙烯醚的电喷雾质谱分析

The mass spectrum rule of the fatty alcohol polyoxyethylene ether(AEO) with different number ethoxy(EO) was discussed by electrospray ionization mass spectrometry(ESI-MS). The main peak of AEO is [M＋Na]^＋ peak, and the response value differ with number of EO. The ionization efficiency is low when the number of EO is high and low, and the ion strength is disproportionate to the concentration of sample, so the value of the number of EO detected should be revised as it is not consistent with actual number. The dimer ＋Na^＋ peak of and trimer＋Na^＋ peak will appear when the concentration of the sample injected or the intensity of the trap ion is high.     

气相色谱-串联质谱法快速测定乳制品中三聚氰胺及其3种类似物

建立了气相色谱-串联质谱(GC-MS/MS)快速测定乳制品中三聚氰胺、三聚氰酸、三聚氰酸一酰胺和三聚氰酸二酰胺的方法。样品用混合溶剂提取后,取少量提取液氮气吹干,硅烷化试剂衍生化后,采用GC-MS/MS多反应监测模式（MRM）测定。三聚氰胺及其3种类似物在0.01～1.0 mg/L浓度范围内均呈现良好的线性关系,线性相关系数分别为0.999 8、0.998 2、0.999 9、0.999 8;检出限均为0.05 mg/kg (S/N=3),加标回收率为92.5%～102.5%。该方法操作简便、快速,能消除乳制品中复杂基质的干扰,结果准确可靠、灵敏度高,适用于乳制品中三聚氰胺及其3种类似物的同时测定。     

顶空气相色谱/质谱法测定香精香科中丁二酮

采用气相色谱-质谱(GC-MS)分析技术,选择离子检测法(SIM),建立了香精香料中丁二酮的测定方法。色谱柱为DB-1 MS石英毛细管柱,电子轰击离子源,选择质谱图中的m/z 43和862个特征离子用于SIM检测,根据这2个离子的抽出离子色谱图的峰面积比进行目标物确证,以基峰m/z 86作定量分析,检出限为0.1 mg/kg。用色谱保留时间、质谱特征离子同时定性,消除了香精样品中复杂基体的干扰,避免了假阳性结果的出现。     

蚕蛹油中脂肪酸组成及其酯型鉴定

采用碱液浸泡法从蚕蛹中提取总脂肪,经甲酯化后,采用GC/MS法分析其脂肪酸的组成及相对百分含量,并用核磁共振 ¹H NMR法鉴别其脂肪酸的酯型。蚕蛹油中含有15种脂肪酸,其中不饱和脂肪酸占71.20%,亚麻酸的相对百分含量高达32.06%,其存在形式主要是脂肪酸甘油酯。