How can ion pairing agents cause peaks to split?

I have previously made a lot of nucleotide analyses with tetrabutylammonium as ion pairing agent but decided out of curiosity to try primary amines instead and then made a strange observation. One...

09 October 2019 4,820 14 View

What is the most proper term for the affinity constant when allosteric effectors are studied in enzyme activity assays?

In Michaelis-Menten experiments the substrate concentration is varied and Km values and Vmax/kcat values are obtained. My question is what corresponding terms are called when it is the allosteric...

08 September 2019 8,704 19 View

Can the loading capacity of ionic compounds on reverse phase HPLC be increased?

I have a good separation of nucleotides on a c18 with tetrabutyammonium ions as ion pairing agent but have a problem that the column so easily get overloaded and the largest peaks get very broad...

07 August 2019 3,192 8 View

How does the choice of ion pairing agent affect the chromatography of multivalent anions?

I am analyzing nucleotides from cells and I have then found that the separation is very good on C18 columns with tetrabutylammonium ions as ion pairing agent. But, as I have discussed in an...

07 August 2019 4,689 2 View

How does the solubility of the buffer in the stationary phase affect resolution in ion-pair RP chromatography?

I analyze nucleotides with tetrabutylammonium ions as ion-pairing agent on a C18 column and I have made an observation that the resolution of the peaks often decreases when I use buffers that I...

07 August 2019 8,155 1 View

How do I know that the fittings in HPLC are optimal?

I usually do not get as high plate numbers as claimed by the manufacturers and been thinking about how I can know if the fittings (nuts + ferrules) are perfectly seated or not. I have used ACE and...

06 July 2019 5,145 16 View

How can I improve the resolution in SPE purification for HPLC?

I am purifying cell samples for HPLC by SPE to analyze nucleotides and want to improve the SPE procedure to get rid of an impurity causing a broad peak in the HPLC analysis. I can get rid of most...

07 August 2018 6,030 4 View

Is there anyway to extend the lifetime of C18 HPLC columns when used in the presence of tetrabutylammonium salts?

I am using C18 HPLC columns to analyze nucleotides but have the problem that their lifetime is so short. I have tried a lot of variatns of ACE columns (C18, C18aq, C18, hexyl-phenyl etc) from...

11 December 2017 2,711 16 View

Looking for Materials with high thermal expansion coefficient and high temperature resistance?

03 March 2021 8,272 1 View

Can we classify HV and LV lines based on line length?

I have dataset which shows the length of power lines. I need to classify the lines based on the line length. Is there a rule to classify the High voltage (HV) and low voltage (LV) lines based on...

03 March 2021 4,116 4 View

Waters 2707 HPLC autosampler problem?

I am using a 2707 waters HPLC device. When I try to inject a sample, it says missing plate or rack. I changed the needle and calibrated its position but I still get the same problem. I even get...

02 March 2021 1,408 1 View

Why almost every element would be metallized in sufficiently high pressure and low temperature?

(This statement is from wikipedia, BTW). What is so special about metallic bond that is limiting high-P low-T state of a matter (as long as individual atoms exist, not white dwarf of neutron star...

02 March 2021 3,309 2 View

How optimize the Size Exclusion Chromatography?

Hello! I'll do a size exclusion chromatography, but I only have an open column, and I'll perform the peptide extraction from yeast, using buffer lysis (sodium phosphate 50 mM/NaCl 30 mM/DNAse and...

01 March 2021 2,215 2 View

Ester cleavage conditions?

Hi all, I need to cleave the ester in Ethyl 2-amino-1H-imidazole-5-carboxylate to make the carboxylic acid and retrieve the product from solution to use in downstream applications of linking to...

01 March 2021 8,766 3 View

Does anyone know HRM channel in a 2 plex QIAGEN Rotor- Gene Q qPCR can be used as a separate channel?

I am going to have 3 different probes in my qPCR work that I am going to do. But I realized that the machine we have in the lab is a Rotor-Gene Q 2plex HRM Platform, saying it has green, yellow,...

01 March 2021 8,544 1 View

I have designed reflectarray element and feeding it though Horn Antenna on HFSS. After full wave simulation, I am not getting desired results?

I have designed reflectarray element to generate OAM beams at 5.8GHz and feeding it though Horn Antenna on HFSS. After full wave simulation, i am not getting desired results i.e Radiation pattern...

01 March 2021 9,701 5 View

Precipitate after adding laemmli buffer to protein solution containing Potassium Acetate?

Hi, I am running a size exclusion chromatography experiment with a buffer containing Potassium Acetate as a salt. I analyse these fractions through SDS-PAGE. After boiling my SEC fractions in...

01 March 2021 2,622 3 View

Any research papers for extraction of nutrient deprivation on macroalgae? Analysed by HPLC-UV and GC/MS. Possibly from macroalgae genus Rhizoclonium?

I am doing my thesis on the nutrient deprivation on the macroalgae Rhizoclonium sp. I will be analysing the levels over a period of roughly 5 days by HPLC-UV and GC/MS. I will be using seawater as...

28 February 2021 6,477 1 View