主题:【求助】基线 Waters LC 1525 Pump, 2478 UV Detector, thanks

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ciaclin
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Sorry, Can not type Chinese in office.

Now I had technical question on the Waters $$lc ( 1525 Pump, 2478 UV detector)

When I apply gradient solvent  on the assay, got some confusion: the baseline @ 205,208, 210 always drift to a high value, the Uv Absorbance reading increased a lots.

However, the baseline @ 260, 278, 340 nm is working 100% well.

Is there any problem at Uv lamp? Or that energy deteriorate or loss?

Thanks for you reply.

--------------------------------------------
最近清理实验室, 想最后评估以下老的Waters $$lc  1525 Pump, 2478 UV Detector.  (实在对他很有感情了, 5年了 , 象老黄牛一样任劳任怨)

使用梯度淋洗, 老是在低波长的时候, 吸收突然增高,基线升高很大。
Min        A:H2O,                B( ACN)
0            85                    15
15          30                    70
20          30                    70
25          85                    15

只要是gradient elute, 就在低波长的地方出现以下情况。
相同的gradient elute 在 1100, 1200 上面,基线很平稳, 一点问题都没有。

是Uv lamp 老化了,? 能量降低?
请各位$$lc 专家帮忙看看原因, 谢谢。

以上文本借助<A href="http://www.inputking.com/"


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您这个问题有点专业,5年前您用低波长检测过吗?当时是什么情况?还有只是水与乙腈做流动相也可以不跑梯度吧?当波长降低后,乙腈会不会对检测有影响?2487的工作波长范围是多少?

这里帮您顶一下,同样期望专业人士的答复……
ciaclin
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原文由 fy32501 发表:
您这个问题有点专业,
5年前您用低波长检测过吗?当时是什么情况?
Not sure, boz the first chemist left 3 years ago. Looked up her
notebook, could not find any record of gradient elute @ Low wavelength.

还有只是水与乙腈做流动相也可以不跑梯度吧?
Sometime do really need gradient elute: for one product with 27 ingredients, so do need 0.1% H3PO4 /ACN gradient elute.

Our general mobile phase in the lab is: 0.1% H3PO4, 0.1 % Formic Acid, o.o5 M Sodium Phosphate ect.. with ACN or MeoH.

当波长降低后,乙腈会不会对检测有影响?
If I am not wrong, for the HPLC grade Acetonitrile, the cut-off wavelength at 198 nm, so supposed is OK @ 205, 210 nm.

2487的工作波长范围是多少?

Maybe 190 nm to 400. At the first company I worked @2005, found the one "crazy" chemist even run the Uv scan on that 2478 detector up to 660 nm.

Also called the Waters, they might reply at Monday, I will keep you posted if have something new.

Thanks for your reply, fy32501.Have a nice weekend.
xjtutfl
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原文由 ciaclin 发表:
Sorry, Can not type Chinese in office.

Now I had technical question on the Waters $$lc ( 1525 Pump, 2478 UV detector)

When I apply gradient solvent  on the assay, got some confusion: the baseline @ 205,208, 210 always drift to a high value, the Uv Absorbance reading increased a lots.

However, the baseline @ 260, 278, 340 nm is working 100% well.

Is there any problem at Uv lamp? Or that energy deteriorate or loss?

Thanks for you reply.

--------------------------------------------
最近清理实验室, 想最后评估以下老的Waters $$lc  1525 Pump, 2478 UV Detector.  (实在对他很有感情了, 5年了 , 象老黄牛一样任劳任怨)

使用梯度淋洗, 老是在低波长的时候, 吸收突然增高,基线升高很大。
Min        A:H2O,                B( ACN)
0            85                    15
15          30                    70
20          30                    70
25          85                    15

只要是gradient elute, 就在低波长的地方出现以下情况。
相同的gradient elute 在 1100, 1200 上面,基线很平稳, 一点问题都没有。

是Uv lamp 老化了,? 能量降低?
请各位$$lc 专家帮忙看看原因, 谢谢。

以上文本借助<A href="http://www.inputking.com/"




UV灯是有寿命的,一般使用时间长了,在低波长段是很不稳定的,特别是在做梯度洗脱的时候.
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guohua
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Hello ciaclin,this problem maybe UV lamp overlife,or flow cell dirty, also your optics unit need change.

You could change UV lamp first, and then pick off flow observe the baseline.
ciaclin
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原文由 guohua 发表:
Hello ciaclin,this problem maybe UV lamp overlife,or flow cell dirty, also your optics unit need change.


Update:

Just replace a NEW Uv lamp and change the flow cell.

When use the isocratic, get a decent baseline @ 205, 210, 220, 279 nm
However, after changing back to gradient, the baseline @ 205,210, 220 nm is a crap.

Any comments would be highly appreciated.
nnsss
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SuDaToKo
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风烟
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不行的话,您就问一下Waters的工程师吧……或者打一下8008202676吧。
希望您的问题早日解决,等解决了分享一下吧……
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