Category: ARTICLES, APPNOTES, FAQ
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Analyzing metformin in plasma samples how do I obtain reproducible results and peak shapes - FAQ
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Are septa in autosampler vial caps self sealing inert and compatible with organic solvents - FAQ
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Are the Cogent TYPE-C Silica based stationary phases available for sale as bulk materials - FAQ
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Are there any solvents that I cannot use with the knitted reactor coils KRC and knitted delay tubes KDT - FAQ
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Can an autosampler needle pierce the Zone Free sealing film and will it reseal afterwards - FAQ
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Can I expect a more predictable retention time with Silica-C columns than with ordinary silica - FAQ
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Can I use a PEEK finger tight fitting on stainless steel tubing - Can I use a SS fitting on PEEK tubing in HPLC - FAQ
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Can I use a silica or Silica-C guard column with an analytical column of a different phase - FAQ
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Can I use phosphoric acid or sodium phosphate with the Cogent Diamond Hydride HPLC column - FAQ
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Can I use the Cogent Diamond Hydride column without mobile phase additives like formic acid - FAQ
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Can the following tube diameters and materials be cut using the Stainless Steel tubing cutter? -FAQ
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Can the U-2D Micro-Sample management system be used in SPE manifold for 96-well plates - FAQ
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Causes of high baseline noise with Cogent Diamond Hydride HPLC column - Tips & Suggestions
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Changing retention times of amino acids in biological extracts using ammonium acetate in HPLC methods. - Troubleshooting.
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Citric acid retention and peak shape has changed compared to data from a previous run what happened - FAQ
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Compatibility guidelines for safety coated mobile phase reservoir bottle use - Tips & Suggestions
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Considerations for keeping gases dissolved in solution when using sparging stones - Tips & Suggestions
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Could your PEEK tubing have contaminants via manufacturing processes from previous extrusion runs - FAQ
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Determining Efficiency of HPLC methods comparing 4um v 2.o HPLC columns - Tips & Suggestions
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Direct silicon to carbon bonds on Cogent TYPE-C HPLC columns produce longer column lifetimes
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Do Cogent TYPE-C Silica columns have a partial positive charge and if so is retention for basic compounds reduced because of this - Tech Information
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Do the MICROSOLV mobile phase delivery bottle caps have holes to insert tubing through - FAQ
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Eliminating shoulder peaks in an HPLC method using Cogent RP C18 columns - Tips & Suggestions
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For sugars analyzed by LCMS sodium acetate is recommended for sensitivity of Na adducts - Tips & Suggestions
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For the separation of polar intermediates in reversed phase HPLC which C18 column do you recommend - FAQ
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Ghost peaks appearing in results using a gradient with TFA which can degrade with time - Tips & Suggestions
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High pressure develops after flushing a Cogent Diamond Hydride column with acetonitrile cause and solution - FAQ
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How can I fix poor peak shape for phosphorylated compounds in aqueous normal phase ANP methods - FAQ
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How can I improve accuracy and precision when separating polar compounds by HPLC using Aqueous Normal Phase ANP - FAQ
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How can I restore my Diamond Hydride HPLC column after I ran out of mobile phase and air was accidently introduced into it - FAQ
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How do I avoid distorted peak shapes when using a basic mobile phase pH for the analysis of a lipophilic amine - FAQ
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How do retention and efficiency of asymmetric dimethylarginine ADMA compare using 4um vs 2.o Diamond Hydride columns - AppNote
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How do the terms nano capillary and micro LC differ in terms of column ID and typical flow rates - FAQ
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How does ammonium fluoride affect HPLC and LCMS data if using Aqueous Normal Phase ANP methods - FAQ
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How long will it take for chloroform to degrade the plastic safety coating on the mobile phase bottles if the bottle is broken during a fall - FAQ
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How often do I need to do the conditioning procedure for a new Diamond Hydride column - FAQ
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How to choose a suitable mobile phase additive for negative ionization mode LCMS - Tips & Suggestions
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How to eliminate retention time drift in LCMS with Aqueous Normal Phase ANP methods - Tips & Suggestions
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How to improve peak shapes, retention & carryover for polar compounds with the Cogent Diamond Hydride™ column - Tips & Suggestions
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How to prepare 10mM ammonium acetate buffer 90:10 in acetonitrile for HPLC and LCMS - Tips & Suggestions
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How to prepare 16mM ammonium acetate buffer 90:10 in acetonitrile for HPLC - Tips & Suggestions
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I am not observing any peaks for succinic acid or alpha-ketoglutarate with the Cogent Diamond Hydride column - Tips & Suggestions
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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
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Identify used U-2D inserts for multiple projects or in small sample sets - Tips & Suggestions
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If an analyte is only soluble at basic pH can you use a basic mobile phase for my method - FAQ
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Injection Technique for Aqueous Samples using Cogent TYPE-C Columns in ANP - Tips & Suggestions
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Is TYPE-C Silica a high purity support and have a low metal content silica like Type B silica - FAQ
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Issues arising from changes in mobile phase with acids to one with ammonium salts. Tips & Suggestions
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LFER studies compared to Log D data in describing the Aqueous Normal Phase ANP retention - Tips & Suggestions
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Lower retention is observed when functional group in a compound is ionized - Tips & Suggestions
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Mobile Phase recommendation Cogent Diamond Hydride columns for use with serum samples in Aqueous Normal Phase LCMS - Tips & Suggestions
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Modify selectivity in an ANP method of HPLC using different mobile phase pH - Tips & Suggestions
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My method uses an standard type-B silica based HPLC column is there a Cogent TYPE-C column equivalent substitute - FAQ
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My retention times are changing after storing my buffer and what could be causing this and tips to help avoid issues - FAQ
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Peaks are broad and non symmetrical in LCMS method using Reversed Phase columns - Tips & Suggestions
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Polar and non polar peptides analyzed by LCMS with an Aqueous Normal Phase ANP method - Tips & Suggestions
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Restoring the initial results with a method for analyzing AMP ADP ATP UDP and GPT in biological extracts - Tips & Suggestions
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Should I use methanol as the organic solvent in HPLC when using Aqueous Normal Phase ANP - FAQ
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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
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Solvents and solutions that should be avoided when using PEEK filters fittings or tubing - Tech Information
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Solving baseline problems in ANP methods with the Cogent Diamond Hydride column - Tips & Suggestions
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The best way to avoid with ion suppression issues in LCMS if you need to use an ion-pair agent - Primer
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The effect of ionic strength of the mobile phase additive for HPLC columns in Aqueous Normal Phase - Tips & Suggestions
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To obtain greater sensitivity than Na adducts for sugars could you add ammonia NH4 instead - FAQ
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Troubleshooting problems with poor HPLC runs before the examining the column - Tips & Suggestions
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Two gradients to use for analysis of hydrophilic and or hydrophobic molecules in the same Aqueous Normal Phase ANP method - Tips & Suggestions
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Type of gradient to use for analysis of hydrophilic and hydrophobic molecules in the same HPLC or LCMS run - Tips & Suggestions
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Understanding some of the differences between HILIC columns and TYPE-C columns - Tips & Suggestions
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Use a low concentration of salt in your mobile phase to avoid ion suppression and build up on your inlet source - Tips & Suggestions
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Using ammonium acetate or formate in an acetonitrile based HPLC mobile phase for Aqueous Normal Phase ANP - Tips & Suggestions
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Using an Aqueous Normal Phase ANP method will sodium ions interfere with succinate when analyzing sodium succinate - FAQ
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Using methanol instead of acetonitrile in an HPLC method should be done with caution - Tips & Suggestions
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Using temperature changes for separations of terpenoids with the Cogent Bidentate C18 and UDC-Cholesterol HPLC columns - Tips & Suggestions
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Using triethylamine TEA in Aqueous Normal Phase ANP methods for simple sugars - Tips & Suggestions
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What are some notable examples of journal articles that feature Aqueous Normal Phase ANP methods in metabolomics studies - FAQ
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What are some of the advantages of using Cogent TYPE-C prep and semi-prep HPLC columns - FAQ
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What are the main differences between Cogent Amide columns and other brands of Amide - FAQ
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What are the temperature specifications of the autosampler vial storage box and cap for 4ml vials - FAQ
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What is the best way to attach the inlet of the knitted reactor coil KRC tubing to the outlet of a tee with a PEEK finger tight fitting that will hold high back pressure - FAQ
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What is the chemical compatibility of the Chemical Resistant Sealing Mats for U-2D Micro-Sample Management System - FAQ
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What is the chemical structure of the ligand in the Cogent DIOL HPLC stationary phase - FAQ
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What is the compatibility of Cogent TYPE-C Silica HPLC columns with UHPLC instruments - FAQ
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What is the difference between the Beta Tools and other similar pliers on the market - FAQ
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What is the durability of the SOLVFIL when used with standard mobile phases and buffered mobile phases - FAQ
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What is the maximum concentration of ammonium fluoride to use in a mobile phase to avoid column damage - Tips & Suggestions
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What is the maximum loading capacity mass injection volume that can be used for a semi prep Cogent TYPE-C HPLC column - FAQ
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What is the maximum salt concentration to use with Cogent TYPE-C HPLC columns with HPLC or LCMS - FAQ
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What is the most effective way to clean HPLC columns after or before use - Tips & Suggestions
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What is the purpose of using isopropanol IPA as part of the mobile phase solvent in ANP methods - FAQ
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What is the recommended sparging stone pore size to use for carbonating applications - FAQ
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What makes non-coated Mobile Phase Reservoir Bottles suitable for use in various temperature environments - FAQ
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What pressure should I expect with a Diamond Hydride 2.o HPLC column at flow rates from 0.2 to 2.0mL / min - FAQ
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What special care should I take to protect my HPLC columns when I am equilibrating them - FAQ
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What type of tubing do I use to connect the guard column holder to analytical columns - FAQ
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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
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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
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Which acid or base additive should I choose for positive or negative ion mode in LC-MS - FAQ
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Which Cogent TYPE-C column do you recommend for the separation of positional isomers by HPLC or LCMS - FAQ
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Which column coupler do you recommend for pairing HPLC columns with guard columns- Tech Information
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Which column do you suggest for Cocaine & metabolite Ecognin separation - Tips & Suggestions
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Which HPLC column ID dimensions are the Hichrom brand guard column holders cat no 82000-GH compatible with - FAQ
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Why am I observing broad split peaks in Aqueous Normal Phase ANP when using acetonitrile and methanol diluents - FAQ
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Why do I see large intermittent pressure spikes in HPLC runs and can it be a defective column - FAQ
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Why does the metal content of a silica particle contribute to the peak shape of my chromatogram in HPLC - FAQ
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Why you should use temperature control with the UDC-Cholesterol column - Tips & Suggestions
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Working with ammonium acetate and LCMS requires attention to cleaning - Tips & Suggestions
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