Category: Trouble Shooting Suggestions
/
/
/
Add 10 micro molar EDTA or medronic acid to mobile phase for better peak shapes - Tips & Suggestions
Read More
Read More
Analyte retention decreases with mobile phase water content using the Cogent Bidentate C18 HPLC column has anything happened to the column - Tech Information
Read More
Read More
Analyze phosphorylated compounds with the Cogent Diamond Hydride column - Tips & Suggestions
Read More
Read More
Analyzing metformin in plasma samples how do I obtain reproducible results and peak shapes - FAQ
Read More
Read More
Aqueous Normal Phase ANP ballistic gradients compared to same in HILIC - Tips & Suggestions
Read More
Read More
Aqueous Normal Phase ANP defined & compared to Reversed Phase & Normal Phase definitions HPLC
Read More
Read More
Are there any solvents that I cannot use with the knitted reactor coils KRC and knitted delay tubes KDT - FAQ
Read More
Read More
Assuring retention of polar compounds in an Aqueous Normal Phase ANP gradient in positive ion mode LCMS - Tips & Suggestions
Read More
Read More
Biological extracts Diamond Hydride columns and LCMS ion source diminished peak height problem - FAQ
Read More
Read More
Buffer concentration can affect ANP retention of acids in HPLC Analyses - Tips & Suggestions
Read More
Read More
Can I choose HPLC mobile phase percentages other than those used in the HSQ Spreadsheet - FAQ
Read More
Read More
Can I expect a more predictable retention time with Silica-C columns than with ordinary silica - FAQ
Read More
Read More
Can I use the Cogent Diamond Hydride column without mobile phase additives like formic acid - FAQ
Read More
Read More
Can the HSQ or PQ qualification kits be used with Waters equipment and Empower chromatography data software - FAQ
Read More
Read More
Changing retention times of amino acids in biological extracts using ammonium acetate in HPLC methods. - Troubleshooting.
Read More
Read More
Citric acid retention and peak shape has changed compared to data from a previous run what happened - FAQ
Read More
Read More
Determining Efficiency of HPLC methods comparing 4um v 2.o HPLC columns - Tips & Suggestions
Read More
Read More
Difficulties with wavelength accuracy readings while performing a PQ of an HPLC - Tips & Suggestions
Read More
Read More
Do different retention times for peaks in the Resolution Test Mixture on different systems impact the integrity of my data - FAQ
Read More
Read More
Do Tanaka Plots for HPLC apply to columns used with Aqueous Normal Phase ANP methods - FAQ
Read More
Read More
Eliminate broad split peaks in Aqueous Normal Phase ANP methods and a methanol diluent- Tips & Suggestions
Read More
Read More
Eliminating shoulder peaks in an HPLC method using Cogent RP C18 columns - Tips & Suggestions
Read More
Read More
For sugars analyzed by LCMS sodium acetate is recommended for sensitivity of Na adducts - Tips & Suggestions
Read More
Read More
Ghost peaks appearing in results using a gradient with TFA which can degrade with time - Tips & Suggestions
Read More
Read More
Glucose pyruvate taurocholic acid gamma glutamylcysteine and other analysis - Tips & Suggestions
Read More
Read More
High molecular weight compounds that won't retain on Cogent Diamond Hydride column try Cogent Bidentate C8 300 - Tips & Suggestions
Read More
Read More
High pressure develops after flushing a Cogent Diamond Hydride column with acetonitrile cause and solution - FAQ
Read More
Read More
How can I make changes to locked cells in the Excel spreadsheet that comes with the HSQ qualification kit - FAQ
Read More
Read More
How can I restore my Diamond Hydride HPLC column after I ran out of mobile phase and air was accidently introduced into it - FAQ
Read More
Read More
How do I avoid distorted peak shapes when using a basic mobile phase pH for the analysis of a lipophilic amine - FAQ
Read More
Read More
How similar fittings for chromatography can differ from different brands in HPLC - Tech Information
Read More
Read More
How tight should an autosampler vial cap be to prevent push through of the septa during injection - FAQ
Read More
Read More
How to choose a suitable mobile phase additive for negative ionization mode LCMS - Tips & Suggestions
Read More
Read More
How to eliminate retention time drift in LCMS with Aqueous Normal Phase ANP methods - Tips & Suggestions
Read More
Read More
How to get improved retention and peak shape for glutamine glutamic acid and aspartic acid - Tips & Suggestions
Read More
Read More
How to improve peak shapes, retention & carryover for polar compounds with the Cogent Diamond Hydride™ column - Tips & Suggestions
Read More
Read More
How to keep the Cogent Diamond Hydride column clean when using blood as a sample - Tips & Suggestions
Read More
Read More
I am not observing any peaks for succinic acid or alpha-ketoglutarate with the Cogent Diamond Hydride column - Tips & Suggestions
Read More
Read More
I see a strange saw tooth type of pattern in the UV baseline using my Cogent HPLC column what is it and how can I fix it - FAQ
Read More
Read More
I see extra peaks in my chromatography when I am not using the same filter - Tips & Suggestions
Read More
Read More
If an analyte is only soluble at basic pH can you use a basic mobile phase for my method - FAQ
Read More
Read More
If I use a buffer at pH 9 at 30 to 35C with the Zero Flow capillaries what lifetime should I expect from them - FAQ
Read More
Read More
Is TFA or formic acid better as an acidic mobile phase additive for Cogent TYPE-C columns - FAQ
Read More
Read More
Issues arising from changes in mobile phase with acids to one with ammonium salts. Tips & Suggestions
Read More
Read More
Lower retention is observed when functional group in a compound is ionized - Tips & Suggestions
Read More
Read More
Modify selectivity in an ANP method of HPLC using different mobile phase pH - Tips & Suggestions
Read More
Read More
My LCMS source was getting white film on it and at the same time the background noise was very low so is my Diamond Hydride column bleeding packing material - FAQ
Read More
Read More
Peaks are broad and non symmetrical in LCMS method using Reversed Phase columns - Tips & Suggestions
Read More
Read More
Protecting HPLC analytical columns and when to use guard columns vs Cogent Column Filters - Tips & Suggestions
Read More
Read More
Restoring the initial results with a method for analyzing AMP ADP ATP UDP and GPT in biological extracts - Tips & Suggestions
Read More
Read More
Retention and or peak shape for citric acid has changed compared to data from a previous HPLC run - Tips & Suggestions
Read More
Read More
Since Cogent TYPE-C columns can be used in Reversed Phase or Normal Phase what do you suggest to switch these solvent systems which are not miscible - FAQ
Read More
Read More
Since Cogent TYPE-C Silica columns use a transition metal catalyst in production what is the presence of any trace quantity on the surface of the stationary phase- FAQ
Read More
Read More
Solvents and solutions that should be avoided when using PEEK filters fittings or tubing - Tech Information
Read More
Read More
Suggestion for separation of phenylephrine HCl acetaminophen and dextromethorphan - Tips & Suggestions
Read More
Read More
The effect of ionic strength of the mobile phase additive for HPLC columns in Aqueous Normal Phase - Tips & Suggestions
Read More
Read More
To obtain greater sensitivity than Na adducts for sugars could you add ammonia NH4 instead - FAQ
Read More
Read More
Troubleshooting problems with poor HPLC runs before the examining the column - Tips & Suggestions
Read More
Read More
Type of gradient to use for analysis of hydrophilic and hydrophobic molecules in the same HPLC or LCMS run - Tips & Suggestions
Read More
Read More
Using a Constant Pressure Method on two Instruments Producing Different Flow Rates- Tips & Suggestions
Read More
Read More
Using an Aqueous Normal Phase ANP method will sodium ions interfere with succinate when analyzing sodium succinate - FAQ
Read More
Read More
Using methanol instead of acetonitrile in an HPLC method should be done with caution - Tips & Suggestions
Read More
Read More
Using the wavelength calibration solution holmium oxide for HPLC UV detector performance qualification - Tips & Suggestions
Read More
Read More
What are some common sources of variance during sample preparation in an analytical application - FAQ
Read More
Read More
What can cause changing retention times and a peak showing up in my blank with a Silica-C column - FAQ
Read More
Read More
What effect does high injection volume have on column performance in Aqueous Normal Phase ANP HPLC- FAQ
Read More
Read More
What is the effect of extra column volume for different HPLC instruments on the same method - FAQ
Read More
Read More
What is the maximum concentration of ammonium fluoride to use in a mobile phase to avoid column damage - Tips & Suggestions
Read More
Read More
What is the maximum salt concentration to use with Cogent TYPE-C HPLC columns with HPLC or LCMS - FAQ
Read More
Read More
What is the most effective way to clean HPLC columns after or before use - Tips & Suggestions
Read More
Read More
What is the purpose of using isopropanol IPA as part of the mobile phase solvent in ANP methods - FAQ
Read More
Read More
What problems can occur when using a dedicated Reversed Phase HPLC instrument for an Aqueous Normal Phase ANP method for the first time - FAQ
Read More
Read More
What type of tubing do I use to connect the guard column holder to analytical columns - FAQ
Read More
Read More
What will the pressure be with a mobile phase of 90% methanol and 10% DI water with a 4.6 x 250mm Cogent TYPE-C HPLC column - FAQ
Read More
Read More
When I run gradients on my HPLC and switch from one gradient to another my baseline shows as negative and if I auto zero it becomes positive for the remainder of the run but when I start again it is negative - Primer
Read More
Read More
Why am I observing broad split peaks in Aqueous Normal Phase ANP when using acetonitrile and methanol diluents - FAQ
Read More
Read More
Why are environmental conditions such as temperature relative humidity that are not specified on the CofA for the UV Calibration Kit - FAQ
Read More
Read More
Why are pipettors not recommended for dispensing non aqueous liquids accurately and precisely - FAQ
Read More
Read More
Why do I have lower than normal back pressure with Cogent Diamond Hydride HPLC columns - FAQ
Read More
Read More
Why do I see large intermittent pressure spikes in HPLC runs and can it be a defective column - FAQ
Read More
Read More
Why does the color of the Holmium Oxide solution for HPLC performance qualification look different than before - FAQ
Read More
Read More
Why you should use temperature control with the UDC-Cholesterol column - Tips & Suggestions
Read More
Read More
Will a different guard column hardware system different from the Cogent system affect my results when using a Cogent column - FAQ
Read More
Read More
Will I protect HPLC columns from samples that get permanently adsorbed to the column by using a syringe filter - FAQ
Read More
Read More