Hello, I am a biomed engineer using GPC of ficolls and dextrans to characterize some transport processes. We just bought a used Waters system with Millennium...
Dating back to the late 70s and early 80s when Waters produced its own manual injector, the U6K, there has been confusion and frustration about how to make...
Thank you all for your help! I actually found out the answer from a waters rep-- if you connect the 'inject' terminals on the back of the 600E to the "chart...
Good afternoon Group- I have come across yet another 'weird' column problem. Here are the specifics: I currently assign a column for each particular method. ...
Dear fellow chromatographers, we are testing Ethanol on "Volatile impurities" by gas chromatography according to the monograph in the European Pharmacopoeia...
matthias.kummer@...
Nov 4, 2005 10:06 am
2189
I know it's a silly notion, but are you certain that your vitamin E standard is still good? Tim missy2hancock <goddess523@...> wrote: Good afternoon...
Eksigent Technologies is a rapidly growing startup company with two groundbreaking HPLC product lines. Our HPLC systems offer dramatic performance improvements...
Update: I have just ran both the standards and my sample on a brand spanking new column. The peak did appear but it looks horrible. The peak shape is not...
Hi Chang, yes, we tested another flask of methanol (no change in peak shape). The quality of the methanol is normally p.A. Since we also tried two different...
matthias.kummer@...
Nov 4, 2005 11:20 am
2193
Are you premixing your mobile phase or are you using a mixing valve? If you are using an HPLC that blends the MP for you it could be a malfunctioning mixing...
George Perham
gperham@...
Nov 4, 2005 12:39 pm
2194
What is the solvent for the standard? If it's ethanol you can expect better peak shape using anhydrous ethanol as compared to 190-proof. This is especially...
George Perham
gperham@...
Nov 4, 2005 4:54 pm
2195
Dear members of this forum, I am working with degradation products and stress conditions and I need an article which is related with the subject I am working....
tequila2@...
Nov 9, 2005 10:02 am
2196
Dear members of this forum, In less than one hour I get the article I need. Thanks a lot again. Diego...
tequila2@...
Nov 9, 2005 11:40 am
2197
this may be of interest http://www.selectscience.net/commPRDetails.aspx?artID=6413&u=62cb253d-cd32-4637-94ca-274d9bfcbed1 best regards VP [Non-text portions of...
Hi Tim No, its not a silly notion! I actually thought that was the issue as well but when I ran my samples which contained Vitamin E, the Standard peak and ...
Hi George and group: I was not premixing my mobile phases prior to use but I used another method which calls for 100% ACN on a new column and I unfortunatley ...
Dear colleague here's a useful separations newletter that comes every 2 or 3 weeks. http://www.selectscience.net/commNWDetails.aspx?mailID=871&email={[email]} ...
Hi everyone, I've just packed a 6' column with mole sieve 5A, which I'm hoping to use for sperating O2 and N2 for isotopic analysis. I'm using a Nafion dryer...
I don't believe you'll be successful. Water is quite strongly held by molecular sieves as is carbon dioxide. You may end up needing to condition your column...
Missy, I have 4 things that you could try. First, lower your injection volume. You may be overloading the columnsince Vitamin E is so large. Second, make sure...
Increase carrier gas flow rate and bakeout time. That should do it. Tim Matt <mblack@...> wrote: Hi everyone, I've just packed a 6' column with mole sieve...
Thanks for the input WRT reactivating the mole sieve. I purged the column for 24hrs at 140C. However, I still cannot get seperation of O2 from N2. I've tried...
Formulation Scientist - Boston, MA A client of ours in Boston, MA is seeking a Formulation Scientist to work in the product development environment to conduct...
hi group, i m working on the Gliclazide and Fenofibrate, developing the HPTLC method by using instrument: HPTLC (Cammag) with linomat 5 applicator. Mobile...
hi dears im working with a GC dani1000. today the flame of FID detector didnt ignite because the AIR PRESSURE of DETECTOR didnt reached to 1.01(bar) and...
Hello Group, i m working on the Gliclazide and Fenofibrate, developing the HPTLC method by using instrument: HPTLC (Cammag) with linomat 5 applicator. Mobile...
Hi Frederick Thank you for your thoughts/suggestions about this crazy issue. I have since tried a few more things...as well as contacted Waters to try to gain...
Dear fellow chromatographers, some time ago I asked for help with the problem described below. Meanwhile we could solve the problem and I consider it...
matthias.kummer@...
Nov 22, 2005 1:02 pm
2212
Dear Friends i am working with quantitative structural-retention mechanism(QSRR°) just i like to discuss some ideas about the molecular mechanism of retention...
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