我的条件. column 250mm*21mm C18. mobile phase methanol and 0,1% formic acid. injection volumn: 2ml. injection mass: 100mg elution condition: 5%-90% 30min and hold 90% 8min
【在 f*******t 的大作中提到】 : 应该是有其他溶剂在里面。
h*7
12 楼
detector? if uv detector, could be the formic acid. you are running gradient .
p*m
13 楼
i already run the control, baseline is very flat.
gradient
【在 h*****7 的大作中提到】 : detector? if uv detector, could be the formic acid. you are running gradient : .
a*z
14 楼
同感 也可能overload了
gradient
【在 h*****7 的大作中提到】 : detector? if uv detector, could be the formic acid. you are running gradient : .
f*t
15 楼
你 sample 溶在啥里边?
【在 p**********m 的大作中提到】 : 我的条件. : column 250mm*21mm C18. : mobile phase methanol and 0,1% formic acid. : injection volumn: 2ml. : injection mass: 100mg : elution condition: 5%-90% 30min and hold 90% 8min
p*m
16 楼
water
【在 f*******t 的大作中提到】 : 你 sample 溶在啥里边?
f*t
17 楼
你的这些条件很奇怪, Reverse phase HPLC,我们一般用DMSO溶解 Sample, sample 里面可以有H2O, MeOH但不能有DCM--我建议你用少量的sample并提高你 starting organic mobile phsae concentration. If not working, change the column. If you want more discussion, you can send your phone number to me.
【在 p**********m 的大作中提到】 : water
d*s
18 楼
楼主的条件在RPLC里面再正常不过了,你说的用DMSO来做溶剂才有点少见。
sample
【在 f*******t 的大作中提到】 : 你的这些条件很奇怪, Reverse phase HPLC,我们一般用DMSO溶解 Sample, sample : 里面可以有H2O, MeOH但不能有DCM--我建议你用少量的sample并提高你 starting : organic mobile phsae concentration. If not working, change the column. If : you want more discussion, you can send your phone number to me.
There will be a broad DMSO peak come out first under uv detector (250, 214) . We can use the peak to check the column/ the system is working fine or not . if you use H2O or MeOH to dissolve the sample, how will you know the system is good?
This may work well for you. I just don't understand why would somebody want to see a broad peak to check the system suitability. 1st of all, a nice chromatographic method should generate sharp symmetric peaks.2nd of all, in analytical labs, people set up acceptance ranges of retention time, resolution, asymmetry,S/N, plate numbers of the compounds of interest. If any of those fails, do troubleshooting or replace consumables. Although sometimes calibration standard(s) may be used to validate UV w
【在 f*******t 的大作中提到】 : There will be a broad DMSO peak come out first under uv detector (250, 214) : . We can use the peak to check the column/ the system is working fine or not : . if you use H2O or MeOH to dissolve the sample, how will you know the : system is good?
f*t
23 楼
Yeah, you do not know a lot of things cause you are from analytical lab. It is a totally different story in organic lab. LZ was trying to seperate not analyze his sample. His column is a typical one for purification up to 100mg sample. 250mmx21.2mm is long and medium not large. but look at yours 2.1mm- -that is for analytical hplc. And LZ's mobile phase normally should be ACN not MeOH. There was no supply of ACN last year. We changed to MeOH for a while until ACN was re-supply. The difference is
【在 d******s 的大作中提到】 : This may work well for you. : I just don't understand why would somebody want to see a broad peak to check : the system suitability. 1st of all, a nice chromatographic method should : generate sharp symmetric peaks.2nd of all, in analytical labs, people set up : acceptance ranges of retention time, resolution, asymmetry,S/N, plate : numbers of the compounds of interest. If any of those fails, do : troubleshooting or replace consumables. Although sometimes calibration : standard(s) may be used to validate UV w
p*m
24 楼
because i use methanol and 60min also include washing step and re- equlibrium step.
lab. It not 100mg 2.1mm- ACN a will with
【在 f*******t 的大作中提到】 : Yeah, you do not know a lot of things cause you are from analytical lab. It : is a totally different story in organic lab. LZ was trying to seperate not : analyze his sample. His column is a typical one for purification up to 100mg : sample. 250mmx21.2mm is long and medium not large. but look at yours 2.1mm- : -that is for analytical hplc. And LZ's mobile phase normally should be ACN : not MeOH. There was no supply of ACN last year. We changed to MeOH for a : while until ACN was re-supply. The difference is
b*r
25 楼
How long ago did you prepare the sample before running? Were the control and sample run at similar time? Formic acid can evaporate rapidly.