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机构地区:[1]徐州工业职业技术学院,徐州221140 [2]徐州市产品质量监督检验中心,徐州221008
出 处:《理化检验(化学分册)》2016年第11期1292-1296,共5页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)
摘 要:茶叶样品(10g)加水20mL浸泡10min后,加乙腈50mL,超声提取5min,加氯化钠5g,振荡,静置分层;取有机相,吹氮至近干,加入丙酮-正己烷(3+7)混合液2mL溶解残渣。所得溶液经Florisil固相萃取柱净化后进行色谱分离。用BEH C18色谱柱作固定相,以不同体积比的甲醇和0.1%(φ)甲酸溶液的混合液作流动相进行梯度洗脱。质谱分析中采用电喷雾正离子和多反应监测模式。外标法定量,基体匹配制作标准曲线。结果表明:印楝素A和B的质量分数均在2.50-50.0μg·kg-1范围内与相应的峰面积呈线性关系,检出限(3S/N)分别为2.5,5.0μg·kg-1。在3个浓度水平上用标准加入法做回收试验,测得回收率为81.6%-95.1%,相对标准偏差(n=6)为1.1%-3.9%。应用此法分析了3种茶叶样品,其中单枞茶中印楝素的残留量最高。The tea sample (10 g) was soaked in 20 mL of water for 10 min, and then extracted ultrasonically with 50 mL of acetonitrile for 5 min. The extract was shaked with 5 g of NaC1 and let to stand for phase separation. The organic phase was taken and evaporated to near dryness by N2-blowing. The residue was taken up with 2 mL of a mixture of acetone and n-hexane (3+7). The solution obtained was purified on Florisil SPE column and then separated by UHPLC using BEH C18 column as stationary phase and mixtures of methanol and 0. 1% (φ) formic acid solution, mixed in various volumic ratios, as mobile phase in gradient elution. In MS analysis, ESI+ and MRM mode were adopted. Quantification was attained by external standard method with preparation of standard curves by matrix-matching method. Linear relationships between values of peak area and mass fraction of azadirachtin A and azadirachtin B were obtained in the same range of 2. 50- 50. 0 μg·kg-1 with detection limits (3S/N) of 2. 5, 5.0μg·kg-1respectively. Tests for recovery were made by standard addition method at 3 concentration levels, giving values of recovery in the range of 81. 6%--95. 1%, with values of RSDIs (n=6) ranged from 1. 1% to 3. 9 %. The proposed method was used in the analysis of 3 different kinds of tea. It was found that among the 3 tea samples, highest amount of residual azadirachtin was given by the Dancong tea.
关 键 词:超高效液相色谱-串联质谱法 印楝素A 印楝素B 残留量 茶叶
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