GC-MS/MS在研究生实验教学中的应用

为开拓学生的专业视野,将大型仪器气相色谱—三重四级杆串联质谱(GC-MS/MS)用于研究生实验教学。在文献调研的基础上,引导学生进行气相色谱条件的选择,协作完成基于单级质谱和串联质谱的定量方法开发,充分发挥学生的主观能动性,提高其科研创新及团队合作能力。将科研项目转化为实验课程,通过比较两套仪器方法对土壤基质样品中硝基苯的测定效果,加深学生对GC-MS(/MS)测试性能的认识,有利于研究生将来开展科研工作。同时从课前预习、对比性教学、课堂问题讨论、课后拓展4个方面积极进行多元化教学方法探索,切实提高大型仪器实验教学效果。通过课程学习使研究生熟练掌握大型仪器使用方法,为公用实验室大型仪器的全面开放使用奠定坚实的基础。     

新技术保障食品安全

质谱仪检测三聚氰胺 美国国家食品安全与技术中心借助三重四极杆质谱仪的先进分析技术,建立了一个新的液相色谱一串联质谱方法测定食品中的三聚氰胺。这种新方法更容易对成分复杂的样品进行快速和有效的分析。测定食品中三聚氰胺残留的现有先进方法,首先是由位于丹佛的食品药品监督管理局动物研究中心建立的。这种检测方法灵敏度高,并且非常耐用。     

液相色谱-串联质谱/质谱法联用检测鸡蛋与蛋制品中的三聚氰胺

建立了检测鸡蛋中三聚氰胺的超高效液相色谱-串联质谱/质谱法.样品用三氯乙酸溶液提取,经阳离子交换固相萃取柱净化后,用液相色谱-串联质谱/质谱法测定和确证,在电喷雾离子化(ESI+)和多反应监测模式条件下,外标法定量.结果表明:该方法线性好,三聚氰胺的线性范围为10～200 μg/L;线性相关系数分别为0.999 9,检出限为0.01 mg/kg;在3个浓度水平加标,三聚氰胺的回收率在85.4%～98.5%之间,变异系数小于10%.该方法灵敏度高、准确度好,非常适用于鸡蛋与蛋制品中三聚氰胺的检测.     

UPLC-MS/MS法测定酒中邻苯二甲酸酯

建立了酒中8种邻苯二甲酸酯的超高效液相色谱-串联质谱联用仪检测方法。白酒、葡萄酒、黄酒等经前处理后,使用Waters ACQUITY UPLC仪和Waters Quattro Premier三级四极杆质谱仪,采用超高效液相苯基反相色谱柱分离,甲醇-水流动相流速0.2 mL/min,进样量2.0μL,电喷雾离子化串联质谱分析检测。该方法专一性强,检测耗时短,定量准确。检测酒中邻苯二甲酸酯的线性范围0.5¹0.0mg/L,检出限0.05 mg/L,回收率86.4%10.0mg/L,检出限0.05 mg/L,回收率86.4%¹04.7%,相对标准偏差小于8.7%。     

超高效液相色谱-电喷雾串联四极杆质谱法测定食品中喹诺酮类药物的残留量

建立了动物源性食品中9种喹诺酮类药物残留量的液相色谱-电喷雾串联四极杆质谱测定方法.样品经阳离子交换固相萃取柱净化后,采用多反应监测(MRM)模式,进行LC-MS/MS分析.方法检出限均为0.05μg/kg,在0.05～50μg/kg添加水平范围内,喹诺酮类药物回收率为65.8%～94.6%,相对标准偏差为5.3%～9.1%.     

液质联用法测定蔬菜和水果中的烟酰胺单核苷酸

建立B-烟酰胺单核苷酸的液相色谱-串联质谱快速测定方法。采用Shim-packVP-ODS(150L×2.0 mm,5μm)色谱柱进行色谱分离,流动相为甲醇与0.1%乙酸水溶液,梯度洗脱12 min,流速为0.3 mL/min,在质谱正离子模式下用多反应离子监测模式进行定量测定。在0.1425-228μg/L的质量浓度范围内线性良好(r=0.9998),回收率为86.6%～108%,RSD为3.4%;重现性好,RSD为2.22%;方法的定量限0.1425μg/L(S/N为10),检出限为0.07μg/L(S/N为5)。该方法灵敏度高、选择性好,适用于蔬菜、水果营养价值分析及药用价值开发研究中B-烟酰胺单核苷酸的快速测定。     

高分辨电感耦合等离子质谱仪测定半导体级硝酸中杂质

利用高分辨电感耦合等离子体质谱测定半导体级高纯硝酸中的痕量金属杂质,用直接稀释法,把浓硝酸稀释10倍后,用标准加入法进行上机检测,前处理简单、快速,避免了在样品前处理时的污染问题。高分辨电感耦合等离子体质谱可以消除多分子离子干扰,降低检出限,提高定量准确性。该方法检出限为0.01～8.6 ng/L,加标回收率为84%～111%。     

气相色谱-质谱联用同时测定沉积物中三氯生和甲基三氯生

建立了气相色谱-质谱联用(GC-MS)技术同时分析沉积物中三氯生和甲基三氯生的方法。采用丙酮提取沉积物样品,提取物经自制C18固相萃取柱净化,利用N-甲基-N(三甲基硅)-三氟乙酰胺(MSTFA)对提取物中三氯生进行衍生化,用外标法进行定量。GC-MS对三氯生和甲基三氯生的检出限分别为0.59ng/g和0.28ng/g,沉积物中三氯生和甲基三氯生不同浓度的加标回收率分别为85.6%~95.7%和84.4%~106.7%,相对标准偏差(RSD)分别为3.5%~6.9%和3.9%~6.3%。对6个沉积物样品进行了分析测定,三氯生和甲基三氯生的浓度分别为12.41~93.77ng/g和4.96~6.48ng/g。研究结果表明,该方法适用于同时测定沉积物样品中三氯生和甲基三氯生的含量,具有检出限低、灵敏度高、重复性好等优点,是一个较为可靠的检测方法。     

化妆品中丁丙倍他米松的定性与定量分析

利用四极杆飞行时间质谱技术检测化妆品中糖皮质激素时,发现了一种新的非法添加到化妆品中的疑似糖皮质激素。该激素具有倍他米松类糖皮质激素结构,但不在法规的检测范围内。在无标准品的情况下,通过QTOF二级质谱的碎片解析并结合碱水解实验,对该疑似糖皮质激素进行了定性研究,确证了该疑似物为倍他米松丁酸丙酸酯;并应用三重四极杆质谱对水解反应产物倍他米松进行定量分析,确定待测样品中丁丙倍他米松的含量为310 ng/mL。本研究为化妆品中非法添加法规外糖皮质激素成分的高通量筛选提供新的思路和方法,是对现有的化妆品中激素检测方法的有效补充。     

UPLC-ESI-MS/MS法测定发酵液中紫杉醇含量

产紫杉醇菌发酵液经乙酸乙酯萃取后,应用Waters ACQUITY UPLC仪和Waters Quattro Premier三级四极杆质谱仪检测建立了产紫杉醇菌发酵液中紫杉醇含量的快速测定方法.采用Waters zXTerra MS C18色谱柱(2.1 mm×150 mm,5μm),梯度洗脱,流速0.3 mL/min,柱温为30 ℃;进样量3.0 μL 以超高效液相色谱分离、电喷雾离子化串联质谱分析在多反应监测(MRM)模式下进行检测 在10～100 μg/mL,紫杉醇对照品的峰面积与浓度线性关系良好,相关系数0.998;方法具有良好的精密度,RSD为0.51％;稳定性试验表明室温下样品在8h内稳定;具有良好的重现性,RSD为1.6％;平均加样回收率为99.58％,RSD为0.62％ 采用MRM模式测定紫杉醇含量不仅可以增加定量准确性,而且专一性强,干扰因素少,还为产紫杉醇微生物的快速筛选提供科学的方法.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

胡主席在印度,我却在中国

Today, Sunday morning, I sit thinking and typing at my computer. My thoughts are in my homeland, India and my body is in China. The body is here and mind there for a good reason. Mr. Hu is president and I am resident and both are in each other's countries (what a difference the absence of one small letter makes!). Mr. Hu will return in a few days and I will stay on longer.