食用调味油样品经丙酮提取后,所得提取液经MCX阳离子固相萃取柱提取,用氨水-甲醇(5+95)溶液洗脱,洗脱液在45 ℃氮吹至近干后用2 mL甲醇定容。以ACQUITY BHE C18色谱柱为分离柱,以不同体积比的0.1%(体积分数)甲酸溶液和甲醇混合液为流动相进行梯度洗脱,采用电喷雾正离子源多反应监测模式检测。罗丹明B的质量浓度在1.00~100 μg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)为0.003 mg·kg-1。在0.01,0.05,0.20 mg·kg-1 3个浓度水平下进行加标回收试验,所得方法的回收率在82.1%~97.2%之间,测定值的相对标准偏差(n=6)均小于9%。

Sample of edible flavoring oil was extracted with acetone, the extracting solution was taken for purification by MCX cation solid phase extraction column. The rhodamine B was eluted from column with a mixture of ammonia (aq.) and methanol (5+95), and evaporated to near-dryness by N2-blowing and made up to 2 mL with methanol. ACQUITY BHE C18 column was used as stationary phase, and the mixture of methanol and 0.1%(φ) formic acid solution with different ratio was used as mobile phase in gradient elution. ESI and multi-reactions monitoring mode were adopted in MS/MS. Linear relationship between values of peak area and mass concentration of rhodamine B was kept in the range of 1.00-100 μg·L-1, with values of detection limit (3S/N) of 0.003 mg·kg-1. Tests for recovery were made at the concentration levels of 0.01, 0.05, 0.20 mg·kg-1 of rhodamine B standard, giving values of recovery in the range of 82.1%-97.2%, with RSD′s (n=6) less than 9%.