兔可食性组织中杆菌肽残留量HPLC-MS/MS测定方法

建立兔可食性组织中杆菌肽残留标志物的HPLC-MS/MS检测方法。兔可食性组织(肌肉、脂肪、肝脏和肾脏)中杆菌肽残留用0.5%三氟乙酸水提取,10%三氯乙酸乙腈沉淀蛋白,正己烷除脂,HLB 150 mg固相萃取柱净化,以0.1%甲酸水和乙腈(0~0.5 min 15%乙腈,7.5~8.0 min 85%乙腈,8.1~10.0 min 15%乙腈)为流动相进行梯度洗脱。采用电喷雾离子源(ESI),正离子扫描,多反应检测(MRM)模式测定杆菌肽含量。杆菌肽在50~1000 ng/g的添加浓度范围内,浓度与响应值之间线性关系良好,相关系数大于0.99,本方法的检测限为30 ng/g,定量限为50 ng/g。杆菌肽平均添加回收率在74.7%~83.8%,批内批间变异系数均小于10%。实验建立的兔可食性组织中杆菌肽残留量的HPLC-MS/MS检测方法可满足兔可食性组织中杆菌肽残留量的检测要求。     

洋虫内产β-葡萄糖苷酶内生菌发酵液转化人参皂苷产物分析及其抗肿瘤活性研究

为提高人参皂苷生物利用度，明确人参皂苷药用洋虫体内生物转化规律及其代谢产物抗肿瘤活性，通过MRS（含七叶苷和柠檬酸铁）培养基筛选洋虫内生菌中高产β-葡萄糖苷酶的菌株，制备复合菌发酵剂液体转化人参皂苷提取物，利用高效液相色谱-串联质谱法分析发酵产物中人参皂苷的化学组成及其动态变化规律，采用四甲基噻唑蓝（methylthiazoletrazolium，MTT）染色法阐明发酵产物低（0.5 mg·L^-1）、中（2 mg·L^-1）、高（5 mg·L^-1）剂量对A549细胞抗肿瘤活性的影响。人参提取物中共检测出Re、Rg1、Rf、Rb1、Rc、Rb2、Rd 7种皂苷，代谢产物中有去糖基化人参皂苷Rh1、Rg3和compoud K产生，发酵产物MTT试验显示高剂量组（5 mg·L^-1）反应72 h抑制肿瘤细胞率可达85%。由此表明，利用洋虫内生菌复合菌液转化人参皂苷提取物可提高中药人参和洋虫的药用价值，为中草药的发酵改性提供了新思路。     

Tissue distribution and changes in dopamine during development and stress responses in Malus germplasm

Dopamine is a catecholamine and an anti-oxidant which functions in responses to stress and it interacts with plant hormones to mediate plant development.  At present, there are few studies on the functions of dopamine in apple.  This study developed a method for dopamine determination which was used to analyze dopamine in Malus germplasm, in order to clarify the tissue distribution, developmental changes, diurnal variations, and stress responses in apple trees.  First, the proposed method was verified.  The linear range of quantification was robust from 0.1 to 20 ng mL^–1.  The instrumental, inter-day precision, and sample repeatability relative standard deviations were 1.024, 5.607, and 7.237%, respectively.  The spiked recovery was greater than 100%, indicating the feasibility of the method and its suitability for the rapid analysis of dopamine in Malus.  Next, the dopamine content was measured in 322 Malus tissues.  The results showed that the dopamine level in Malus was low and the average dopamine content in leaf was higher than in peel and flesh.  The dopamine had a skewed distribution that deviated to the right in cultivars and wild accessions.  Finally, the tissue specificity, developmental changes, diurnal changes, and responses to stress were analyzed.  In cultivar ‘Pinova’ (Malus domestica), the dopamine concentration was the highest in leaf buds and lowest in flesh.  The dopamine contents in leaf and flesh decreased with the growth and development of cultivar ‘Liangxiang’ (Malus domestica).  The dopamine content of apple leaves was higher after either drought or salinity stress as compared to the control.  In this study, a dopamine detection method for apple was established based on HPLC-MS and shown to be a robust approach.  This study provides a framework for future research on elucidating the tissue distribution, developmental changes, diurnal variation, and stress responses of dopamine in apple trees.     

高效液相色谱-串联质谱法测定鸡肉中癸氧喹酯的测量不确定度评定

分析了影响应用高效液相色谱-串联质谱法测定鸡肉中癸氧喹酯残留量的测量不确定因素,并对各不确定度分量进行了量化计算,最终求得扩展不确定度为0.56μg/kg,分析表明重复测量、制备标准溶液及内标溶液引入的不确定度分量是影响癸氧喹酯残留量测量不确定度的主要因素。