d******s 发帖数: 674 | 1 能展开说说为啥QTRAP没有3Q的定量好?俺觉得QTRAP 本质上就是3Q,只是最后一个Q加
了俩voltage barrier。当做3Q来用的话跟3Q没啥区别。
最近做了个project,小分子定量,在T家的QUANTUM跟在AB 家的QTRAP上做(当然是用
在3Q模式),dynanmic 都还好,比较来说都差不多。
俺倒是很同意5500不值得花那么多钱,不过应该比5000灵敏度会高一些(只是听说,没
自己做过比较,所以也不好下定论),加上EPI, MS3等等附加的trap功能,如果有钱
没地方花的话,俺也不介意弄一个在实验室玩玩,呵呵。 |
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s********m 发帖数: 748 | 2 请问用Qtrap得到的data做Mascot search的时候parameter如何设置? 我按照公司给的
参数好像结果不是很好。我之所以说不好是因为同一个样品我用LTQ做的时候多发现了
很多peptide,大概十几倍,感觉不太正常。我LTQ的peptide tol is 800ppm, MS/MS
is 0.6Da, instrument type is ESI-trap, 请问这三项Qtrap一般该如何设置?还有
其他需要特别注意的吗?
如果这些都不是主要问题的话,我不知道是不是实验本身的问题了,希望哪位熟悉此仪
器的高手给点建议, 谢谢 |
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s********m 发帖数: 748 | 3 I know this, but I am using Qtrap to do MRM analysis, so I need the peptide
identification information from Qtrap first. |
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f********e 发帖数: 2194 | 4 LTQ is much better for qualitative peptide analysis than Qtrap. |
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l*****f 发帖数: 13466 | 6 多谢哈。不过 4000 qtrap 我觉得还好?
我赶紧让他们给5000的quote吧。Thanks! |
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f********e 发帖数: 2194 | 7 5500是qtrap,不是trap,比纯qqq好,灵敏度极高,U形CC,省体积
定量很好,不过由于灵敏度太高经常要稀释样品,hehe |
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f********e 发帖数: 2194 | 8 我说错了,是U形collision cell。
QTrap的trap是可作Q,也可做trap,所以没有你说的问题 |
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s**********8 发帖数: 25265 | 9 qtrap 是U型的? thermo varian啥的是吧 |
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S***x 发帖数: 2012 | 10 【 以下文字转载自 Chemistry 讨论区 】
发信人: Sciex (LCMSMS), 信区: Chemistry
标 题: Used API 4000 Qtrap LC-MS/MS for sale
发信站: BBS 未名空间站 (Thu Jul 23 21:04:47 2009, 美东)
包括安装和第一年的保修
感兴趣的话,请发站内邮件给我 |
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L****r 发帖数: 333 | 11 QTRAP做MS/MS功能强大,做peptide没问题,但QTRAP的m/z 上限是1500, 如果楼主用
QTRAP测蛋白的话, 就要用multiplecharge,但QTRAP的resolution不高,建议楼主用
QTOF。 |
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m****e 发帖数: 255 | 12 I am having difficulty repeating a method which was run on Sciex QTrap. I
am using Agilent QQQ. I am monitoring 5-10 ions in each time segment. The
quantification did not have enough data points to quantify... Usually when
this happens I need to work on my my chromatography conditions to get more
seperation. But in order to repeat this method, I have to monitor many ions
at each time segment.
I don't know if I made the question clear. Could anyone who used both Qtrap
and triple quad give |
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k*****m 发帖数: 5 | 13 Postdoctoral opportunity at UCSD:
I am helping my former mentor look for a postdoc. Please send your
application directly to Professor Naviaux.
Here's the job posting:
The Naviaux Lab at the University of California, San Diego has an immediate
opening for a postdoc (MD, PhD, or both) with broad experience in the mass
spectrometry of small molecules and metabolomics. Specific experience with
the quantitative analysis of organic acids, amino acids, nucleotides, thiol
compounds, neurotransmitters, ... 阅读全帖 |
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s**********8 发帖数: 25265 | 14 来自主题: Mississippi版 - 等狼兄奔 low energy的可以解不错 象qtrap high的差 还得靠人 然后用软件confirm |
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k*****m 发帖数: 5 | 15 Postdoctoral opportunity at UCSD:
I am helping my former mentor look for a postdoc. Please send your
application directly to Professor Naviaux.
Here's the job posting:
The Naviaux Lab at the University of California, San Diego has an immediate
opening for a postdoc (MD, PhD, or both) with broad experience in the mass
spectrometry of small molecules and metabolomics. Specific experience with
the quantitative analysis of organic acids, amino acids, nucleotides, thiol
compounds, neurotransmitters, ... 阅读全帖 |
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m*******h 发帖数: 896 | 16 QTRAP 里面当然也可以用 Most Nth . 就是一般的IDA, 不MRM.
first criteria可以是Intensity, second的可以是另外一个参数, 比如说Mass range,
charge state
identification.
trap |
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S***x 发帖数: 2012 | 17 包括安装和第一年的保修
感兴趣的话,请发站内邮件给我 |
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m*******h 发帖数: 896 | 18 What scan speed (amu/sec) you used in ABI Q-Trap, and in Agilent Triple Q?
make sure they are in the same range?
The
when
more
ions
Qtrap |
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w*********l 发帖数: 5144 | 19 把dwell time改改吧 看看你HPLC的锋多宽 50 to 100 ms should be ok
The
when
more
ions
Qtrap |
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s********m 发帖数: 748 | 21 really? That's so strange why the results get so different. |
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l*****f 发帖数: 13466 | 22 定量小分子分析,5500的优势有哪些呢?
多谢 |
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l*****f 发帖数: 13466 | 23 嗯,我跟sales要5000的quote,他说5500是他们的“future in terms of platform
technology”
5000的5500都能做到而且更好? |
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s**********8 发帖数: 25265 | 24 那是忽悠你 价钱高 trap的dymanic range 没有triple Q 的好 对定量是个死穴 |
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s**********8 发帖数: 25265 | 26 说的就是这个 trap的dynamic range. |
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f********e 发帖数: 2194 | 27 只有abi的5500的collision cell是U形的 |
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c******m 发帖数: 884 | 28 小分子(PK)和大分子(peptide, proteins)用的MS/MS主要区别是什么?
QTRAP (Linear Ion Trap + Quadrupole) 可以用来测 peptide 和 protein 吗?
感谢各位大牛,帮帮忙吧。 |
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b*******g 发帖数: 1309 | 29 Ion trap 做ID 的优势 一个是 可以多级MSn, 另外一个是ion accumulation,灵敏度高
QQQ 适合MRM,linear range 比较广
其实如果硬要做precursor ion scan,并且用ion trap, 可以看看 AB 的QTRAP,结合
了两者的优势 QQ+linear ion trap |
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k*****m 发帖数: 5 | 30 Postdoctoral opportunity at UCSD:
I am helping my former mentor look for a postdoc. Please send your application directly to Professor Naviaux.
Here's the job posting:
The Naviaux Lab at the University of California, San Diego has an immediate
opening for a postdoc (MD, PhD, or both) with broad experience in the mass
spectrometry of small molecules and metabolomics. Specific experience with
the quantitative analysis of organic acids, amino acids, nucleotides, thiol
compounds, neurotransmitters, ... 阅读全帖 |
|
u*********t 发帖数: 45 | 31 各位LC/MS/MS高手:
实验室准备买一台二手LC/MSMS。主要用于杀虫剂定量检测,有时也要用于寻找和签定
未知化学物质。
知道agilent的三级四杆质谱仪在定量方面做得很好,但和其它公司三级四杆质谱仪一
样,定性方面不强。也有推荐AB Sciex 的QTrap。还有WATERS的QTOF。
希望板上高手给予指点。谢谢了。 |
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r*****m 发帖数: 3619 | 32 ABsciex 是发明 MRM 定量方法的鼻祖。
它的 QTRAP 搞的非常奇葩,弄了一个ion trap 的设计,但是设计就是只能做到 MS3,
所以定性还是不够,可以用作需要 MS3 鉴定结构的定量。 |
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u*********t 发帖数: 45 | 33 谢谢了!深夜还指点。
还请问,你是推荐QTRAP吗? |
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u*********t 发帖数: 45 | 34 谢谢各位!
初步决定是AB SCEIX 4000 QTRAP. 觉得信价比比较合适,而且预算也不多,只能买这
一档次的。
Thermo 的销售代表可能比较牛吧,到现在也没有答复。也好,借机会了解下FUSION
orbitrap |
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s*******c 发帖数: 179 | 35 If quantitation is major task, go for Sciex Qtrap. If ID is major task, go
for Thermo QE. |
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x**********0 发帖数: 33 | 36 POSITION SUMMARY
A Senior Scientist who will play a key role in new drug characterization and
analysis using LC/MS in research and development. Major responsibilities
include bioanalytical assay development for drug DMPK studies and peptide/
protein and antibody analysis in support of drug candidate selection,
preclinical and IND-enabling studies
ESSENTIAL FUNCTIONS
- Peptide/protein and antibody analysis using Agilent QTOF
- Developing in vitro DMPK assays using SCIEX QTRAP including meta... 阅读全帖 |
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c******m 发帖数: 884 | 37 小分子(PK)和大分子(peptide, proteins)用的MS/MS主要区别是什么?
QTRAP (Linear Ion Trap + Quadrupole) 可以用来测 peptide 和 protein 吗?
感谢各位大牛,帮帮忙吧。 |
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f********e 发帖数: 2194 | 38 业内很少有用QTrap做protein,小肽应该没问题。 |
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c******m 发帖数: 884 | 39 多谢回复,
QTrap上限好像是2800,的确是只能做小肽了。
业界是不是都用Maldi-tof? |
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c******m 发帖数: 884 | 40 定性,后期可能作定量。
老板还想用Qtrap做SILAC...我有点怀疑可行性。 |
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b*******g 发帖数: 1309 | 41 一个orbitrap 可以买两台 Qtrap了吧
lz 还是应该上Q-TOF 比较靠谱
定性定量都能兼顾到,当然有钱还是直接上Orbitrap |
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f****6 发帖数: 4472 | 42 来自主题: Pharmaceutical版 - 发个面经 东北部某大药厂clinical bioanalysis position for fresh PhD and PhD with 1-2
years postdoc experiences,这个职位要求同时有大分子和小分子经验
提前一天下午到,晚上和hiring manager以及她的老板(director)吃了个晚饭
第二天早晨9点面试,hiring manager半小时(简单介绍了一下以前做过的一个project
然后各种behavior questions),不同组associate director半小时 (介绍了几个以前
做的projects然后各种behavior questions),HR半小时(主要讨论compensation和visa
),presentation半小时加15min Q&A
11点半到1点和组里几个associate principal scientists吃饭聊天(聊我的
presentation,我的经历,公司的pipeline,公司所在地的生活情况等)
下午1点开始,不同组director半小时(各种behavior questions),hiri... 阅读全帖 |
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x**********0 发帖数: 33 | 43 POSITION SUMMARY
A Senior Scientist who will play a key role in new drug characterization and
analysis using LC/MS in research and development. Major responsibilities
include bioanalytical assay development for drug DMPK studies and peptide/
protein and antibody analysis in support of drug candidate selection,
preclinical and IND-enabling studies
ESSENTIAL FUNCTIONS
- Peptide/protein and antibody analysis using Agilent QTOF
- Developing in vitro DMPK assays using SCIEX QTRAP including meta... 阅读全帖 |
|