Topiramate, Retention of a Sulfonate Drug by LCMS – AppNote

Retention of the Sulfonate Drug Topiramate The structure of Topiramate leads us to think due to the Amino group and negative Log P value of -0.8, it will not be retained in Reversed Phase HPLC. However, in this Method, the compound is well retained. Peak: Topiramate 340.1062 m/z (M + H)+ Method Conditions: Column: Cogent […]

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Felodipine Extended-Release Tablets USP Assay – AppNote

USP Method for Felodipine ER Tablets This method presents the USP Felodipine Extended-Release Tablet assay using the Cogent RP C18. As shown in the chromatogram with a five injection overlay, the peak efficiency is superb and USP peak tailing guidelines are easily met with the Cogent RP C18™ column.  This demonstrates a great alternative Column […]

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Cyclobenzaprine Hydrochloride USP Assay – AppNote

This method demonstrates the USP Cyclobenzaprine Hydrochloride Extended-Release Capsules Assay. As shown in the Chromatograms, the peak efficiency is superb and USP peak tailing guidelines are easily met with the Cogent RP C18 5μm column. This demonstrates a great alternative column for easy plug and play and this UPS Assay Method. Method Conditions: Column: Cogent […]

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Amlodipine, Valsartan, and Hydrochlorothiazide Tablet USP Assay – AppNote

This AppNote demonstrates the USP Method for Amlodipine, Valsartan, and Hydrochlorothiazide Tablets working with the Cogent RP C18. As shown in the Chromatograms, the Peak efficiency is superb and USP Peak tailing guidelines are easily met with the Column. This demonstrates a great alternative Column for easy plug and play with this USP Method. Method […]

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Dimethylolpropionic Acid – AppNote

Hydrophilic acid retention on the Cogent Diamond Hydride™  Dimethylolpropionic Acid is a unique diol molecule with both hydroxyl and carboxyl functionality and presents several challenges in chromatographic analysis. Traditional reversed phase mode may not be viable due to the high hydrophilicity of this organic acid. Also, by lacking chromophores it can be difficult to detect […]

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Analysis of a Local Anesthetic Lidocaine, Aminoethylamide – AppNote

Method Development for a Local Anesthetic (A Case Study) An analyst was using a Cogent Diamond Hydride™ Column for evaluating Lidocaine methods and although they had good retention of the compound, they did not meet the required 0.3 – 0.5 AU when 0.1 mg/mL Lidocaine sample was injected for both 2μL and 10μL injection volumes. […]

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Psychoactive Compounds Analysis in Cannabinoids – AppNote

Cannabinoid Separation Method Due to the number of expanding products of homeopathic extracts from Hemp, there is an equally increasing necessity to accurately analyze and separate the numerous compounds from these natural samples. While Cannabidiol has been extracted for multiple natural remedies, there is also numerous unwanted psychoactive constituents and related compounds that may also […]

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Morphine Sulfate Tablet HPLC Method Transferred to Near UHPLC – AppNote

Standard 4um Particle Size Transferred to 2.o™ This application illustrates how methods developed using the 4µm Cogent Diamond Hydride Columns may be adapted for Cogent Diamond Hydride 2.o™ phases. Morphine shows slightly higher retention on the 2.o™ Column (average 7.311 min vs. 5.588 min). The efficiency is almost twice as high when using the smaller […]

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Ketorolac Separation with LCMS – AppNote

Analgesic agent There is a need for analysis of the Active Pharmaceutical Ingredient (API) in Ketorolac Tablet formulations in order to evaluate two different extraction protocols. The use of Ethanol as the extraction solvent was explored initially but DI Water was observed to produce superior extraction efficiency. The chromatograms show how the compound can be […]

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Nitrofurantoin Capsule Analyzed with HPLC – AppNote

Isocratic Separation of API from USP internal standard The USP assay method for the active pharmaceutical ingredient (API) found in Nitrofurantoin Capsules, uses a Phosphate Buffer and is not compatible with Mass Spectrometry. In this AppNote, using the Cogent Bidentate C18 Column, Formic Acid is used as the Mobile Phase additive, as such, the method […]

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Bi-Est® Method Transfer – AppNote

4μm to Near-UHPLC – Separation of Hormones: Estriol, Estradiol, and Progesterone Separation of three components of a hormone replacement formulation is demonstrated in this Application Note using the Cogent Bidentate C18 2.o™ Column. The two figures demonstrate how comparable retention can be obtained for both the near-UHPLC column as well as the standard 4μm Column, […]

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Aegeline in Protein Sport Mix – AppNote

LC-MS analysis of harmful substance in food supplement The data demonstrates the use of the Cogent Bidentate C18 2.o™ Column for analysis of dietary supplement samples. Isolation of the Aegeline peak is readily obtained with an extracted ion chromatogram (EIC) in the positive ion mode. Chromatographically, the peak is well retained and highly symmetrical. The […]

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Resveratrol Capsule – AppNote

Isocratic Separation of Isomers In this easy isocratic method, the cis and trans isomers of Resveratrol are separated using a near-UHPLC stationary phase. The Cogent Bidentate C18 2.o™ Column produces excellent efficiency for both analyte peaks. The sample used here is an actual capsule formulation, demonstrating the suitability of the column for real-world samples. With […]

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Metaldehyde in Slug Pellets Analyzed by LCMS – AppNote

Pesticide Formulation As Metaldehyde is a non-UV absorbing compound, other detection methods needed to be investigated besides conventional UV-HPLC. LC-MS was found to be a well-suited analysis by searching for the EIC corresponding to the [M+H]+ ion. Good retention and peak shape were observed for this analyte using the Cogent Bidentate C18 2.o™ Column. Peak: […]

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Coricidin HBP Night® Tablet – AppNote

Acetaminophen, Dextromethorphan, and Chlorpheniramine This Method demonstrates the potential of the Cogent Phenyl Hydride 2.o™ Column for analysis of amine-containing analytes in a real formulation. Chlorpheniramine and Dextromethorphan can often be problematic in terms of peak tailing due to the tertiary amines, but this column and method produces excellent peak shapes for both compounds in this […]

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Analysis of Isobaric Opioids by LCMS – AppNote

Separation of Isobaric Drugs Morphine and Hydromorphone are Isobaric Drugs (the same m/z value) that can be separated using the Cogent Bidentate C18 2.o™ Column. Multiple samples (n=5) were prepared and analyzed. The results showed great reproducibility (RSDs < 3%). The detection limits were 50 to 500 times lower than that required by immunoassays. Peaks: […]

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Doxycycline and Methacycline Analyzed with HPLC – AppNote

Simple Isocratic Method for API and Main Impurity Formulations of Doxycycline may contain a Methacycline Impurity.  As such, it is crucial for analytical methods to be able to separate these two peaks. Using this simple isocratic Method, the baseline resolution is obtained for this pair. Peaks: 1. Methacycline 2. Doxycycline * Impurities in doxycycline standard […]

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Peonidin-3-Glucoside Analyzed by LCMS – AppNote

LC-MS method for Anthocyanin- Fruit or Vegetable Extracts In this analysis, the presence of Peonidin-3-O–Glucoside was confirmed in two out of four extracts. The peaks were symmetrical and retained beyond the dead volume. Due to the MS detection and comparison of the retention time, it was possible to find the peak for Peonidin-3-O-Glucoside among many […]

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Glycosidic Flavonoids Analyzed with HPLC – AppNote

Separation of Diosmin, Eriocitrin, and Naringin In this method, three Glycosidic flavonoid standards are separated with good resolution. The Cogent Bidentate C18 2.o™ Column produces high efficiency peaks with reproducible retention (see figure overlay). Separation is also observed for a small impurity peak, eluting between peaks 1 and 2. This separation of standards could be […]

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Limonin in Orange Juice Analyzed by LC-MS – AppNote

Separation from Matrix Peaks with Reproducible Results Analysis of Limonin in Spiked Orange Juice was performed using a simple isocratic method with MS detection. Analysis at 471.2 m/z allowed for detection of only the Limonin peak without interference of the juice matrix. When the Filtered, Unspiked Orange Juice was injected, a small peak for Limonin […]

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Oral OTC Anesthetic Analyzed with HPLC – AppNote

Isocratic HPLC Method for Phenol in Oral OTC Products This Method shows how an assay of Phenol can be readily performed with a simple isocratic Mobile Phase. Phenol is the active ingredient in this common Over-The-Counter oral spray solution, which is intended for treatment of sore throat. A number of inactive ingredients are present in […]

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Docusate Sodium Analyzed with HPLC – AppNote

A Simple Gradient with Good Separation    The official USP assay method for Docusate Sodium tablets calls for a Mobile Phase of 50% 7mM Ammonium Acetate / 50% Acetonitrile at 40°C. However, retention for the API and the System Suitability compound Methyl Paraben were found to be low using these conditions. This Method not only […]

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Hydroxytryptophan (5-HTP) Analyzed with HPLC- AppNote

Separation from Vitamin B6 Pyridoxine (Vitamin B6) is often added to formulations of 5-Hydroxytryptophan (5-HTP), as it assists in the conversion of 5- HTP to Serotonin. Therefore, it is of interest to separate these two compounds for an HPLC assay Method of this combination formulation. The Method shown provides good resolution between the two peaks […]

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Doxylamine Succinate Tablet Analyzed with HPLC – AppNote

Shorter Run Time than USP Method The USP Assay Method for Doxylamine Succinate tablets uses Triethylamine and Sodium Lauryl Sulfate in the Mobile Phase. These reagents are slow to fully load onto the Column, resulting in long run times and poor Robustness. This Method uses Trifluoroacetic Acid to get an excellent Peak Shape. An overlay […]

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Ketotifen Analyzed with HPLC – AppNote

API with a Tertiary Amine can have a Great Peak Shape The tertiary amine group of Ketotifen makes it a challenging compound to analyze in HPLC.  In addition to good peak shape for this API, another peak can be identified which is baseline resolved from the main peak of interest. This Method is suitable for […]

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Atorvastatin Drug Product Analyzed with HPLC

API Well Separated from Degradation Product Using this Simple Linear Gradient, Atorvastatin is well separated from its main degradation Product. The degradant is formed under acidic conditions and therefore its Separation is important for Stability Indicating Methods for pharmaceutical formulations of Atorvastatin. For Methods requiring non-degrading conditions, it is important to choose diluent and Mobile […]

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Nucleoside Analogs Analyzed with HPLC – AppNote

Polar and Non-Polar Anticancer Prodrugs Analyzed in the Same Run In this Method, we display Retention of both polar and nonpolar compounds in a simple Isocratic run. Adjustment of the aqueous to organic ratio can be used to make either the polar or more hydrophobic compounds elute first. In the example presented, the more hydrophobic […]

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Quinine Sulfate and Impurity Analysis with HPLC – AppNote

API Separation from Impurity without Ion-Pair Reagents The USP Method for Quinine Sulfate requires a Resolution of not less than 1.2 from its main impurity, Dihydroquinine. In the USP Method, the ion pair agents Methanesulfonic Acid and Diethylamine are used in the Mobile Phase. Ion pair agents are often needed to reduce peak tailing of […]

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Cefpodoxime Proxetil Analyzed with HPLC – AppNote

USP Assay Method an Antibiotic Prodrug The USP Assay Method for Cefpodoxime Proxetil specifies a Resolution of not less than 2.5 between the two epimers of the Prodrug. Using this Method, the average Resolution was calculated to be 2.8. In addition, the R-epimer tailing factor must be not more than 1.5 where this Method meets […]

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Carvone and Loratadine Analyzed with HPLC – AppNote

Linear Gradient In Normal Phase Mode on a C18 Column for Selectivity Carvone and Loratadine have similar Polarity but in this Method, they can be separated while maintaining significant Retention (k > 2). When the Mobile Phase of 95% Hexane and 5% Dichloromethane is used, the Loratadine is infinitely retained. This Normal Phase Analysis shown […]

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Purine Nucleotides Analyzed with HPLC- AppNote

Separation of Xanthosine -5’-Monophopate and Guanosine -5’-Triphosphate This Method achieves the separation of Nucleotides XMP from GTP. The analysis of these polar compounds is achieved at high concentration of an organic Solvent as part of the Mobile Phase which provides increased Sensitivity. Retention times were very Reproducible with %RSD approximately 0.4, even when Red Blood […]

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Cancer Prodrug Analyzed with HPLC – AppNote

Separation Achieved with Shape Selectivity and Hydrophobic Interaction This Method provides an example of Reversed Phase Separation containing a number of related compounds. The properties of the solutes are listed in the Table below. When comparing the properties of Compounds 2 and 3, it is interesting to note that 2 is more hydrophobic than 3 […]

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Benzonatate Excipients & Degradants Analyzed with HPLC – AppNote

A Simple, Linear Gradient for a Challenging Drug Product This Gradient Method will produce a good separation of Benzonatate from excipients and degradants in a USP Capsule Formulation. Benzonatate contains a secondary amine group, which can cause peak tailing. Peak:  Benzonatate Method Conditions Column: Cogent Bidentate C18™, 4μm, 100Å Catalog No.: 40018-75P Dimensions: 4.6 x […]

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Cyanuric Acid and Melamine Analyzed with LCMS – AppNote

Simple Gradient Method with MS Detection This Method by LCMS detection eliminates derivatization which may be necessary with GCMS Methods.  Reversed Phased Methods may run into poor separation of the small and very polar Melamine, resorting to ion pairing reagents to improve separation.  The use of these ion pairing reagents counterintuitively results in ionization suppression […]

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Monoclonal Anti-A1-Glycoprotein – AppNote

Glycoprotein Analysis  For the last few decades Glycoproteins have been a subject of interest to biochemists and biologists in many fields. These proteins are found in plasma and other biological fluids and they serve many functions in nearly every physiological process of living organisms. These macromolecules consist of a peptide chain and one or more […]

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Analysis of Nucleotides – AppNote

ATP & AMP Separated in Aqueous Normal Phase (ANP) The chromatogram below shows an example of the separation possible with this Method for three Adenosine analytes using an Aqueous Normal Phase (ANP) Gradient. Peaks: 1. Adenosine-3’,5’-Cyclic Monophosphate 2. Adenosine 5’-Monophosphate (AMP) 3. Adenosine 5’-Triphosphate (ATP) Method Conditions Column: Cogent Diamond Hydride™, 4μm, 100Å Catalog No.: […]

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Vitamin K Isomers Analyzed with HPLC – AppNote

Phytonadione Separation by Shape Selectivity In this Method, we separate the two E and Z isomers of Phytonadione on the basis of shape selectivity. The below chromatogram is a five injection overlay with a resolution value of 1.5.  Peaks: 1. Impurity 2. Phytonadione (E isomer) 3. Phytonadione (Z isomer) Method Conditions Column: Cogent UDC-Cholesterol™, 4μm, […]

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ATP, UDP-Glucose UDP-Galactose Separation from Red Blood Cells – AppNote

Separation of Nucleotides  In this application, we present an easy-to-use protocol for sensitive detection and quantification of nucleotides in red blood cell extracts.  Retention times were very reproducible with %RSD around 0.4. The desired separation between UDP-Glu and UDP-Gal was achieved, all other nucleotides eluted later and did not interfere with the analysis. ATP represents […]

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Prednisone Quantitation Method – AppNote

Simple and Easy Prednisone Analysis with LCMS Detection This Method does not require any type of derivatization. Two Gradients are presented which will allow you to choose one depending on other components in the sample and your Method objectives. Retention can be achieved on a very short column (50 mm) as shown. Linear gradient conditions […]

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Application Notes – AppNotes Listed by Compound

This list of links to Knowledge Base Articles on this Site, showcase Methods of Separation for each of the Compounds below and the Cogent Column used.  Not all of our Application Notes are listed below and to find other Applications, call our Customer Service Department at 1-732-380-8912 between 9-5 EST or use our Click To […]

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