Hello. My name is Juanjo Serrano and I studied Chemistry in Universidad de Valencia (Spain). I created two groups about Chemistry (one in YAHOO! and the other...
Hi Does anyone know what the Mark-Houwink constants for poly caprolactone are, in chlorofom at 30ºC (or any other temperature). Any help would be greatly...
Dear all, Because of the specific nature of my project, I have to use MTBE (methyl tertiary-butyl ether) or ethyl acetate as the mobile phase, which...
Dear all, Commonly, people use ACN to precipitate proteins out of plasma sample and then inject the supernatant to LC-MS/MS. This procedure is called...
I'm looking for somewhere to buy or repair the filament for my PerkinElmer QMass 910. PerkinElmer no longer carries the replacement part so I'm looking for...
hello I am presently involved in the seperation process.My basic aim is to seperate lactic acid. I need some basic concepts as to which seperation is best like...
Hello, I will be running some assays for sunscreen active ingredients. On the side, is there any way to predict if any of the inactive ingredients in the...
Hi, We are developing an SPE/HPLC method for PAH's down to 0.02ppb levels in water. We are using a reveresed phase SPE cartridge and HPLC with fluorescence...
Hello, I am going towork on a NCD255 and I would like to know exactly how it works, the difference with thermal energy analyser (TEA) and the main publications...
That would depend on several questions: 1. what is your formulation? 2. are you using reversed phase? 3. what type of sample preparation are you performing? 4....
shiffty@...
May 8, 2003 1:15 am
1571
Hi, What type of cartridge are you using? If you are using a plastic cartridge I would replace it with a glass cartridge. Have you tried pre-rinsing the SPE...
shiffty@...
May 10, 2003 3:31 pm
1572
I seem to remember a similar question on the www.abrf.org discussion board. You might try searching their archives. ... sample ... those ... inject ... them...
Hello, In US there´s a a definition of Associate chemist ,but is a little unbiquous... this is a college degree,or a post high school short course?Is the same...
Researchers, I'm interested in dry-packing my own HPLC stainless steel columns. Can anyone please share their experience and "know-how" advise? Just for...
Hi, does anyone have experience with the AS3000 autosampler? We are having serious problems about reproducibility between injections (rsd>1% when the...
Dear All member of Chrom-L, My research is about separation of phenols groups using MeCN and water as eluen in many varying concentration. I got trouble in...
im new to this whole chromatography thing, this question probabily wont trouble anyone. i need to define a situation in which a given analyte provides a ...
Hy chromatographers, I must envelope an analythical method for surfactants (Triton X- 100). Can someone help me? I have a GC with FID detector and capillary...
Perhaps there is just a simple answer...?! I am validating a qualitative GC-MS screen method and have come across a thing that puzzels me. The LOD is esimated...
Hi i am a new member, i just found this gruoup and it seemed to me very useful, because i´m finishing a master and at the moment i´m doing an investigation...
Hi, We have a Varian GC and Finnegan Incos quadrupole MS. I can get reasonable results with simple hydrocarbons, caffeine, aspirin etc but nothing with PAH's,...
There is no standard definition of terms. In our laboratory the term associate is used for a newly hired chemist. If the chemist progresses in a couple of...
shiffty@...
May 26, 2003 5:17 pm
1583
What type of column are you using and who is the manufacturer? Mike ... groups using MeCN and water as eluen in many varying concentration. I got trouble in...
shiffty@...
May 26, 2003 5:20 pm
1584
Check the HPLC application notes from Waters, Agilent, Restek, or Supelco. If you have a C8 or c18 column run ~ 60:40 Water:ACN at 1 to 2 mL a minutes flow...
shiffty@...
May 26, 2003 5:29 pm
1585
Hi, There is no simple answer because the term LOD is not standardized. In our laboratory (pharmaceuticals) we define LOD as 3 x the signal to noise but we do...
shiffty@...
May 26, 2003 5:38 pm
1586
Hi, Triton X-100 is octoxynol-9. There is an HPLC method in the NF portion of the USP/NF that is designed to analyze nonoxynol-9 in the presence of ...
The Shifflet's
shiffty@...
May 26, 2003 6:54 pm
1587
My PAH problem seems to be solved. I spent a day pulling everything apart and found that the column had been installed incorrectly. The length of column in...
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