m****n
发帖数: 354 | 1 在学校里是做 protein post-translational modification (e.g. phosphorylation),
当然用的是 LC-MS/MS (flow rate 小 ). 最常用的是ABI 的 QSTAR(quadrapole-time
of flight). 去年年底毕业，没有直接找到工作(weak)，只好去作博士后 (non-profit
)了。因为找工作的过程中发现 LC-MS在小分子方向的机会比较多。 所以博士后就选择
了小分子方向 (analytical pharmacology)，目前就是做一些 pre-clinical and
clinical的 PK的样品。 刚来的时候还觉挺充实的，毕竟接触新的领域, 学了不少东西
。 可是，几个月之后发现好像用 LC-MS/MS定量也就是那子。 老板本来说叫我作 ADME
high throughput screening/biomarker, 来了之后 Biomek workstation也就是有大
量 PK样品的时候用用。还天天叫我写 proposals. 原来根本就没有什么grant 可以让
我作 | E***n
发帖数: 308 | 2 your background sounds fine. Gain as much DMPK experience as possible. I
believe you will get a job after 2 yrs postD.
what's the difference between LC-MS/MS定量 and simple LC quantification?
),
time
profit
y)，目前就是做一些 pre-clinical and
ADME
【在 m****n 的大作中提到】
: 在学校里是做 protein post-translational modification (e.g. phosphorylation),
: 当然用的是 LC-MS/MS (flow rate 小 ). 最常用的是ABI 的 QSTAR(quadrapole-time
: of flight). 去年年底毕业，没有直接找到工作(weak)，只好去作博士后 (non-profit
: )了。因为找工作的过程中发现 LC-MS在小分子方向的机会比较多。 所以博士后就选择
: 了小分子方向 (analytical pharmacology)，目前就是做一些 pre-clinical and
: clinical的 PK的样品。 刚来的时候还觉挺充实的，毕竟接触新的领域, 学了不少东西
: 。 可是，几个月之后发现好像用 LC-MS/MS定量也就是那子。 老板本来说叫我作 ADME
: high throughput screening/biomarker, 来了之后 Biomek workstation也就是有大
: 量 PK样品的时候用用。还天天叫我写 proposals. 原来根本就没有什么grant 可以让
: 我作
| m****n
发帖数: 354 | 3 Thanks. here is my two cents.
LC-MS/MS is usually more specific because of MRM by tamdam MS, shorter LC
run (also due to higher specificity) and more sensitive (for triple
quadruple). For LC quantification, you need to find a way to detect it by
somehow (UV, Vis etc)beside separation, which limits its application. I don'
t know why it's usually not as sensitive as LC-MS/MS. LC-MS/MS method for
the same drug might vary a lot in differnt matrixes (matrix effect). There
are also different concerns
【在 E***n 的大作中提到】
: your background sounds fine. Gain as much DMPK experience as possible. I
: believe you will get a job after 2 yrs postD.
: what's the difference between LC-MS/MS定量 and simple LC quantification?
:
: ),
: time
: profit
: y)，目前就是做一些 pre-clinical and
: ADME
| K******S
发帖数: 10109 | 4 you have pretty good chance. I guess H1b and those laid-off employees from
this year caused the bad situation. Keep it up. It's actually hard to find
ppl who has both protein (proteomics) and small molecule experience. You
will be fine in a few years.
),
time
profit
ADME
【在 m****n 的大作中提到】
: 在学校里是做 protein post-translational modification (e.g. phosphorylation),
: 当然用的是 LC-MS/MS (flow rate 小 ). 最常用的是ABI 的 QSTAR(quadrapole-time
: of flight). 去年年底毕业，没有直接找到工作(weak)，只好去作博士后 (non-profit
: )了。因为找工作的过程中发现 LC-MS在小分子方向的机会比较多。 所以博士后就选择
: 了小分子方向 (analytical pharmacology)，目前就是做一些 pre-clinical and
: clinical的 PK的样品。 刚来的时候还觉挺充实的，毕竟接触新的领域, 学了不少东西
: 。 可是，几个月之后发现好像用 LC-MS/MS定量也就是那子。 老板本来说叫我作 ADME
: high throughput screening/biomarker, 来了之后 Biomek workstation也就是有大
: 量 PK样品的时候用用。还天天叫我写 proposals. 原来根本就没有什么grant 可以让
: 我作
| h*****t
发帖数: 1226 | 5 UV and vis ofcourse has lower sensitive ty than MS, but if the stuff can be
detected by fluorensence, MS if out of the question.
don'
【在 m****n 的大作中提到】
: Thanks. here is my two cents.
: LC-MS/MS is usually more specific because of MRM by tamdam MS, shorter LC
: run (also due to higher specificity) and more sensitive (for triple
: quadruple). For LC quantification, you need to find a way to detect it by
: somehow (UV, Vis etc)beside separation, which limits its application. I don'
: t know why it's usually not as sensitive as LC-MS/MS. LC-MS/MS method for
: the same drug might vary a lot in differnt matrixes (matrix effect). There
: are also different concerns
| d*o
发帖数: 2345 | 6 @.@same background as me. | b*****r
发帖数: 203 | 7 Since you are doing LC-MS/MS, why there is still a lot of matrix effect?
For LC-MS, you can quantitate it by their ion intensity. Of course, you need
control the spray condition similar or use an internal standard to
normalize the different electrospray condition. If you know what molecules
you are looking at, you can use an isotope labeled same molecule (heavy
isotopes such as C13 instead of D are better, since it won't have
significant effect on the retention time). In this case, you will have
【在 m****n 的大作中提到】
: Thanks. here is my two cents.
: LC-MS/MS is usually more specific because of MRM by tamdam MS, shorter LC
: run (also due to higher specificity) and more sensitive (for triple
: quadruple). For LC quantification, you need to find a way to detect it by
: somehow (UV, Vis etc)beside separation, which limits its application. I don'
: t know why it's usually not as sensitive as LC-MS/MS. LC-MS/MS method for
: the same drug might vary a lot in differnt matrixes (matrix effect). There
: are also different concerns
| K******S
发帖数: 10109 | 8 "Since you are doing LC-MS/MS, why there is still a lot of matrix effect?"
Are you talking about the matrix used on MALDI.
The "matrix effect" that ID said is another different story.
need
【在 b*****r 的大作中提到】
: Since you are doing LC-MS/MS, why there is still a lot of matrix effect?
: For LC-MS, you can quantitate it by their ion intensity. Of course, you need
: control the spray condition similar or use an internal standard to
: normalize the different electrospray condition. If you know what molecules
: you are looking at, you can use an isotope labeled same molecule (heavy
: isotopes such as C13 instead of D are better, since it won't have
: significant effect on the retention time). In this case, you will have
| b*****r
发帖数: 203 | 9 I'm not talking about MALDI matrix. I'm just saying if there is some matrix,
during LC run, it will be eluted out first or eluted out at different
retention time, then where is the matrix effect?
【在 K******S 的大作中提到】
: "Since you are doing LC-MS/MS, why there is still a lot of matrix effect?"
: Are you talking about the matrix used on MALDI.
: The "matrix effect" that ID said is another different story.
:
: need
| w********g
发帖数: 447 | 10 sure. in biological samples, it is very common to see more than 1000 peaks
by flow injection. it's hard (or i should say no way) to remove matrix
effect completely. solving the ion suppression problem caused by the matrix
effect is one of the most challenging parts in metabolomics study
matrix,
【在 b*****r 的大作中提到】
: I'm not talking about MALDI matrix. I'm just saying if there is some matrix,
: during LC run, it will be eluted out first or eluted out at different
: retention time, then where is the matrix effect?
| K******S
发帖数: 10109 | 11 biological samples are much more complex than that. You will have matrix
effect quite frequently. You can wish those matrix stuff will be eluted
first or at other retention times, but you can't count on it.
matrix,
【在 b*****r 的大作中提到】
: I'm not talking about MALDI matrix. I'm just saying if there is some matrix,
: during LC run, it will be eluted out first or eluted out at different
: retention time, then where is the matrix effect?
|
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