Category: Trouble Shooting Suggestions
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Analyzing metformin in plasma samples how do I obtain reproducible results and peak shapes - FAQ
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Back Pressure That is Lower than Normal Using a Cogent Diamond Hydride HPLC Column - Tech Information
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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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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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Difficulties with wavelength accuracy readings while performing a PQ of an HPLC - Tips & Suggestions
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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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Formic Acid Improves Peak Shapes Retention and Carryover for Polar Compounds With the Cogent Diamond Hydride HPLC Column - Tips & Suggestions
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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 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 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 Tight Should an Autosampler Vial Cap be to Prevent Push Through of the Septa During Injection - HPLC Primer
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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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Is TFA or formic acid better as an acidic mobile phase additive for Cogent TYPE-C columns - FAQ
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Lower Retention When Functional Group in a Compound Should be Ionized - Troubleshooting Tips
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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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Phosphorylated Compounds Analyzed with Cogent Diamond Hydride Columns - Tips and Suggestions
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Polar and Mixed‑Polarity Metabolites Strategy Using Panel Method Cogent Diamond Hydride - Tips and Suggestions
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Restoring a Cogent Diamond Hydride Column After Air Exposure - Ran Out of Mobile Phase - Troubleshooting
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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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Retention Time Difference in the Resolution Test Mixture on Different Systems Does Not Impact the Integrity of Data - Tech Informaton
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Selectivity Modification in an ANP Method Using Different Mobile Phase pH - Tips & Suggestions
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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
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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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The effect of ionic strength of the mobile phase additive for HPLC columns in Aqueous Normal Phase - Tips & Suggestions
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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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What are some common sources of variance during sample preparation in an analytical application - FAQ
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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 maximum concentration of ammonium fluoride to use in a mobile phase to avoid column damage - Tips & Suggestions
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What problems can occur when using a dedicated Reversed Phase HPLC instrument for an Aqueous Normal Phase ANP method for the first time - 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 Pipettors not Recommended for Dispensing Non Aqueous Liquids Accurately and Precisely - 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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