Category: HPLC Tips and Suggestions
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10mM Ammonium Acetate Buffer 90:10 in Acetonitrile Preparation for HPLC and LCMS - Tips & Suggestions
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Analyzing metformin in plasma samples how do I obtain reproducible results and peak shapes - FAQ
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Aqueous Normal Phase ANP and How it is Useful for Polar Compound Separation - Tech Information
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Avoid Spurious Peaks from Nylon Syringe Filters with DI Water Using Electrochemical Detection - Tips & Suggestions
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Baseline Problems in ANP Methods with the Cogent Diamond Hydride Column - Tips and Suggestions
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Better Methods Than HILIC for Polar Compound Analysis in HPLC and LC‑MS - Tips & Suggestions
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Biological Extracts - Troubleshooting for Diminished Peak Height Using Cogent Diamond Hydride™ Columns - Tech Information
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Broad Peaks That are Non Symmetrical in LCMS in Reversed Phase Solutions - Troubleshooting
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Buffer Concentration can Affect ANP Retention of Acids in HPLC Analyses - Tips and Suggestions
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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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Choose a Suitable Mobile Phase Additive for Negative Ionization Mode in LCMS - Tips & Suggestions
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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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Cocaine and Polar Metabolites ( Ecgonine) Separation using LC‑MS / MS - Tips and Suggestions
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Crimped Cap Removal from Fused Insert Vials Without Damaging the Insert - Tech Information
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Effects of Washing and Re-using Autosampler Vials on Sample Loss and Contamination - Tech Information
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Eliminate Retention Time Drift in LCMS With Aqueous Normal Phase ANP Methods - Tips & Suggestions
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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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Formic Acid Improves Peak Shapes Retention and Carryover for Polar Compounds With the Cogent Diamond Hydride HPLC Column - Tips & Suggestions
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High Pressure Develops after Flushing a Cogent Diamond Hydride HPLC Column with Acetonitrile Cause and Solution - FAQ
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High‑Molecular‑Weight Compounds Fail to Retain on the Cogent Diamond Hydride Column — and the Correct Column to Use - Tips and Suggestions
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How Can I Fix Poor Peak Shape for Phosphorylated Compounds in Aqueous Normal Phase ANP Methods - Tips & Suggestions
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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 Separate Methacrylic Acid and Dodecyl Benzene Sulfonic Acid - Tips & Suggestions
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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 - Tips & Suggestions
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How Does Ammonium Fluoride Affect HPLC and LCMS Data if using Aqueous Normal Phase ANP Methods - HPLC Primer
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How Tight Should an Autosampler Vial Cap be to Prevent Push Through of the Septa During Injection - HPLC Primer
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How to calibrate UV-vis and HPLC detectors with NIST traceable solutions below 230nm - Tips & Suggestions
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How to Get Improved Retention and Peak Shape for Glutamine Glutamic Acid and Aspartic Acid - Tips & Suggestions
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How to handle sparging stones to avoid contamination of mobile phases - Tips & Suggestions
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Hydrophilic and Hydrophobic Molecules Separation in the Same Aqueous Normal Phase ANP Method - 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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Increasing Selectivity and Resolution for a Xylose and Ribose HPLC Method Resolution - Tips & Suggestions
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LCMS Challenges with HILIC Mobile Phases from Salt Buildup and Ion Suppression Explained - 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 When Functional Group in a Compound Should be Ionized - Troubleshooting Tips
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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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No Peaks for Succinic Acid or Alpha-kKtoglutarate With the Cogent Diamond Hydride LCMS Column - Tips & Suggestions
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Optimizing Separation of Polar and Non‑Polar Analytes Using Cogent TYPE‑C Silica™ Columns - Tech Information
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Polar and Mixed‑Polarity Metabolites Strategy Using Panel Method Cogent Diamond Hydride - Tips and Suggestions
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Positive or Negative ion mode Salt Suggestions for LC-MS Method Development - Tips & Sugeestions
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Prepare a 16mM Ammonium Acetate Buffer 90:10 in Acetonitrile for HPLC - Tips & Suggestions
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Restoring the Initial Method Results Analyzing AMP ADP ATP UDP and GPT in Biological Extracts - Troubleshooting
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Retention And or Peak Shape for Citric Acid has Changed Compared to Data from a Previous HPLC Run - Tips & Suggestions
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Retention Decrease as Mobile Phase Water Content Increases on a Cogent Bidentate C18 Column - Troubleshooting
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Selectivity Modification in an ANP Method Using Different Mobile Phase pH - Tips & Suggestions
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Serum Samples Use Suggestion for Cogent Diamond Hydride Columns in LCMS Methods - 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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Simple Sugars Methods using Triethylamine TEA in Aqueous Normal Phase ANP Methods - Tips & Suggestions
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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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Sodium Ion Interference in ANP Methods: Challenges in Analyzing Sodium Succinate - Tips & Suggestions
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Suggestion for separation of phenylephrine HCl acetaminophen and dextromethorphan - Tips & Suggestions
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Tandem HPLC Columns in One Separation for Polar and Non Polar Compounds - Tips and Suggestions
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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 Results Before Examining the Column - Tips & Suggestions
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Using a Constant Pressure Method on two Instruments Producing Different Flow Rates- Tips & Suggestions
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Using Ammonium Acetate or Ammonium Formate in Diamond Hydride Methods - Tips & Suggestions
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Using methanol instead of acetonitrile in an HPLC method should be done with caution - Tips & Suggestions
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Vials Listed as 12 x 32 mm Compatibility with Autosamplers' Maximum Diameter of 11.8 mm - HPLC Primer
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What are some common sources of variance during sample preparation in an analytical application - FAQ
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What are the Temperature and Pressure Limits for Amber Glass Autosampler Vials - Tech Information
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What are the typical flow rates recommended by HPLC column companies to start with for various column ID - Primer
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What can cause changing retention times and a peak showing up in my blank with a Silica-C column - FAQ
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What effect does high injection volume have on column performance in Aqueous Normal Phase ANP HPLC- FAQ
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What is the effect of extra column volume for different HPLC instruments on the same method - FAQ
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What is the Functional Difference Between the MRQ and the Max Recovery Autosampler Vials - HPLC Primer
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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 purpose of using isopropanol IPA as part of the mobile phase solvent in ANP methods - 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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Why am I observing broad split peaks in Aqueous Normal Phase ANP when using acetonitrile and methanol diluents - FAQ
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Why are ionized polar compounds generally better retained in Aqueous Normal Phase ANP HPLC - 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 you should use temperature control with the UDC-Cholesterol column - Tips & Suggestions
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Will a different guard column hardware system different from the Cogent system affect my results when using a Cogent column - FAQ
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