提出了QuEChERS净化-高效液相色谱-串联质谱法(HPLC-MS/MS)测定吊浆粑中米酵菌酸含量的方法。取2.0 g样品,加入10 mL水,涡旋1 min;然后加入10 mL含5%(体积分数)乙酸的乙腈溶液,涡旋1 min;再加入6.0 g无水硫酸镁和1.5 g无水乙酸钠,涡旋1 min,离心5 min。取5 mL上清液置于预装200 mg C₁₈和900 mg无水硫酸镁的15 mL离心管中,涡旋1 min。取2 mL上清液,于40 ℃氮吹至干,用1 mL 50%(体积分数)乙腈溶液复溶,涡旋1 min,经0.22 μm尼龙滤膜过滤后进行HPLC-MS/MS检测。色谱分析中以不同体积比的0.1%(体积分数)甲酸溶液和甲醇的混合溶液为流动相进行梯度洗脱;质谱分析中以电喷雾离子源负离子模式电离,多反应监测模式检测,采用基质匹配的标准溶液绘制工作曲线,外标法定量。结果显示:米酵菌酸工作曲线的线性范围为1~200 μg·L^-1,检出限为0.75 μg·kg^-1;在5个加标浓度水平下,米酵菌酸的回收率为78.9%~112%,测定值的相对标准偏差(n=6)为4.2%~16%。

A method for the determination of bongkrekic acid in fermented corn flour by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) with QuEChERS purification was proposed. The sample (2.0 g) was taken, and 10 mL of water was added, and the mixture was swirled for 1 min. Then 10 mL of acetonitrile solution containing 5% (volume fraction) acetic acid was added, and the mixed solution was swirled for 1 min. Then 6.0 g of anhydrous magnesium sulfate and 1.5 g of anhydrous sodium acetate were added, and the mixture was swirled for 1 min and centrifuged for 5 min. The supernatant (5 mL) was taken, and placed into a 15 mL-centrifuge tube preloaded with 200 mg of C₁₈ and 900 mg of anhydrous magnesium sulfate, and the mixture was swirled for 1 min. The supernatant (2 mL) was taken and blown to dryness by nitrogen at 40 ℃, then the residue was redissolved with 1 mL of 50% (volume fraction) acetonitrile solution. After vortex for 1 min, the above solution was filtered with 0.22 μm nylon filter membrane, and then tested by HPLC-MS/MS. In the chromatographic analysis, the mixed solution composed of 0.1% (volume fraction) formic acid solution and methanol at different volume ratios was used as mobile phase for gradient elution. In the mass spectrometry analysis, the electrospray ion source with negative mode was used for ionization, and the multi-reaction monitoring mode was used for detection. The matrix matching standard solutions were used to draw the working curve, with external standard method for quantification. As shown by the results, the linear range of the working curve was 1-200 μg·L^-1, with detection limit of 0.75 μg·kg^-1. At 5 spiked concentration levels, the recoveries were in the range of 78.9%-112%, and RSDs (n=6) of the determined values were in the range of 4.2%-16%.