4-(Methylamino)butyric Acid Analyzed with HPLC- AppNote

A gamma-Aminobutyric Acid (GABA) Derivative  This challenging polar compound is easily retained in this simple Method where repeatability of the data is excellent with %RSD<0.1 for the Retention Times. Peak: 4-(Methylamino)butyric Acid Method Conditions: Column: Cogent Diamond Hydride™, 4μm, 100Å Catalog No.: 70000-15P-2 Dimensions: 4.6 x 150mm Mobile Phase: —A: DI Water with 0.1% Formic […]

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Acetaminophen & Impurity Analyzed with HPLC – AppNote

APAP Drug Substance Analysis with HPLC This Method has been developed for determination of Acetaminophen as a Drug Substance. The Separation was achieved on a C18 Column using Gradient Elution. The Method shown here has excellent Reproducibility of Acetaminophen for 5 consecutive Chromatograms shown had 0.03% RSD. This could be used for Quality Control of […]

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Acetaminophen Impurities Method with HPLC – AppNote

Acetaminophen – Alternate USP Method Acetaminophen and two of its major impurities were analyzed using a simple Mobile Phase. The Peak Shapes are very good and the Repeatability was good (%RSD = 0.01). Peaks: 1. 4-Aminophenol 1.072 minutes 2. Acetaminophen 4.668 minutes 3. 4-nitrophenol 7.588 minutes Method Conditions: Column: Cogent Bidentate C18™, 4µm, 100Å Catalog […]

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Alprazolam (Xanax®) HPLC Method Transferred – AppNote

Benefit of 2.2um Column Analyzing Alprazolam with HPLC In this AppNote, we show that a transfer from a 4µm to 2.2µm Column, higher efficiency is observed with the smaller particle size Column. This can be very useful for analyses requiring detection at low concentrations. The Peak shape is very sharp using the 2.2um Column (Figure. […]

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Alprazolam Analyzed with HPLC – AppNote

Robust Separation of API from USP Internal Standard The USP Assay Method for Alprazolam uses a bare Silica Column and a complex Mobile Phase consisting of Acetonitrile, Chloroform, Butyl Alcohol, and Acetic Acid. In this Method, a simple LCMS compatible Mobile Phase is used and produces excellent Peak shapes for both the API and its […]

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Amikacin & Tobramycin – AppNote

Highly Polar Antibiotic Separation These two Antibiotic agents present a considerable challenge to chromatographers. As highly hydrophilic compounds, they are generally poorly retained by conventional Reversed Phase methods that rely on an analytes hydrophobicity. In addition, they exhibit very low UV absorption and therefore more sophisticated detection methods are often required. In this application, an […]

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Amiloride and Triamterene in Urine – AppNote

LCMS Method for Spiked Urine Sample This application note describes the separation of two important  drugs for treatment of hypertension and congestive heart failure. Both compounds have numerous amine groups, which can contribute to Peak tailing in some instances. However, the Peak shapes observed here are both symmetrical and very efficient. This is accomplished using […]

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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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Amoxicillin Analyzed Orthogonally with HPLC – AppNote

Orthogonal Analysis to USP Assay Method for Validation The USP Assay Method for the antibiotic Amoxicillin is performed in Reversed Phase. Analysis by an Orthogonal Retention mode is very useful and can be readily done by Aqueous Normal Phase (ANP) mode of HPLC, using solvents common to both. A benefit of this Method is the […]

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Amoxicillin USP Assay with HPLC – AppNote

Alternate L1 Column used for the USP Assay Method for Amoxicillin This USP Amoxicillin Assay is performed and a five injection overlay shows Run to Run consistency and Precision. The Peak Efficiency is very good and Peak Tailing guidelines are easily met with RSD values less than 0.3%. This demonstrates a good alternate Column for […]

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Amoxicillin, USP Method with HPLC – AppNote

Robust Analysis of Amoxicillin, Antibiotic with HPLC The USP Assay Monograph Method for Amoxicillin often yields poor Peak shapes and low Method reproducibility with L1 Columns based on ordinary Silica. In contrast, the Figures shown here illustrate the high degree of reproducibility obtained from use of the Cogent Bidentate C18 L1 Column, following the USP […]

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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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Analysis of Clopidogrel with LCMS – AppNote

Analysis of the API and Degradants A Sensitive, Selective, and rapid LCMS Method was developed for the simultaneous Quantification of Clopidogrel (Plavix®) and degradants. This Method can be used for the determination of Clopidogrel in commercial tablets for Quality Control with an application for content uniformity test. The Method is also stability-indicating as it is […]

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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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Analysis of MDMA in Plasma Samples with LCMS – AppNote

Methylenedioxymethamphetamine Analyzed with MS Under the described conditions, MDMA was retained and eluted as a Symmetrical Peak. The Sensitivity of the Method is very good and  comparable to that reported with GCMS Detection [1]. Matrix effects were of minor extent and reproducible and hence should not compromise Quantification. The Method can be used for Forensic […]

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Antibiotic Keflex Analyzed with HPLC – AppNote

Analysis of Polar Antibiotic Main Active Ingredient: Cephalexin Monohydrate Cephalexin Monohydrate, commercially known as Keflex, is a semi synthetic Cephalosporin antibacterial drug, analysis of which is of great interest to scientists from many research fields. There is a need for a rapid, efficient and inexpensive analytical method to be applied for analysis of formulations during […]

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Aspirin & Salicylic Acid Analyzed with HPLC- AppNote

Excellent Peak Shape For a Very Difficult Compound This Method is easy to prepare, use, reproduce and a good Separation of Aspirin from its major hydrolysis product, Salicylic Acid is achieved. Peaks: 1. System Peak 2. Aspirin (Acetylsalicylic Acid) 3. Salicylic Acid Method Conditions Column: Cogent Bidentate C18™, 4μm, 100Å Catalog No.: 40018-75P Dimensions: 4.6 x […]

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Atenolol Tablet Analyzed with HPLC – AppNote

Quick Analysis without Ion Pair Agents The USP Assay Method for Atenolol uses Heptane Sulfonate and Dibutyl Amine in the Mobile Phase, which are slow to load and remove from a Reversed Phase HPLC Column. These reagents are added to improve the Peak Tailing, which must be not more than 2.0. The Method in this […]

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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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Atorvastatin HPLC Method Transfer to UHPLC – AppNote

Transfer to “near-UHPLC” 2.2um Column, for the API Atorvastatin This Application Note demonstrates how data obtained on a 4μm Cogent Bidentate C18 Column (Figure B) can be adapted for a 2.2μm Column (Figure A). The retention times of both analytes are very comparable in each figure. This Method produces excellent Separation of the API and […]

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Atropine Analyzed with a Gradient Method – AppNote

No Ion Pair Reagent Necessary Chromatographic separation and quantification methods of Atropa Alkaloids are often described in the literature and the method of choice is usually Ion-Pair Chromatography (IPC), which requires long equilibration times and it is not very robust. This method shows a symmetrical peak for Atropine using a simple Gradient Method that does […]

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Baclofen Analyzed with HPLC – AppNote

Very Polar API Retained with Precision This compound has two ionizable functional groups (an amine and a carboxylic acid), which makes it quite suitable for retention using this Method. A simple Gradient produced a very sharp Peak for this Analyte. These Method conditions can be applied to the routine Analysis of Baclofen Tablet formulations. Peak: […]

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Barbiturates Analyzed with LCMS – AppNote

Standard Solutions in Human Urine Spiked with Barbiturates After minimal sample preparation (dilute-and-shoot approach), spiked urine samples were analyzed using a C18 Column. The analysis was based on a Separation of Standards [1]. The obtained Peaks were Symmetrical (As<1.05) and Efficient (> 106 pl/m). No shift in retention Times was observed after the samples were diluted […]

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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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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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Bisacodyl Tablet Analyzed with HPLC – AppNote

Separation of API from Matrix Peaks from an Over The Counter Tablet This Method for Analysis of a Bisacodyl Tablet formulation Separates the API from several small matrix Peaks. These Peaks must be Resolved from the main Peak in order to ensure accurate Quantitation. The data below illustrates the separation potential of the this Method […]

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Brazilian Tree Bark Analyzed with LCMS – AppNote

Identification of Quercetin, Rutin, and “Compound 1” in a Brazilian Tree Bark Over one quarter of natural medicines have been discovered in rainforests, and therefore analytical study of the indigenous flora and fauna is necessary. The Amazonian rainforest in Brazil is the most biodiverse region in the world. A Brazilian tree bark extract (Brownea Grandiceps) […]

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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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Capsaicin in Topical Solution Analyzed with HPLC – AppNote

Separation of Capsaicinoids in an OTC Formulation A  formulation of Capsaicins is used as a topically applied solution for Arthritis pain relief. Analyzing Capsaicin and a similar compound, Dihydrocapsaicin is required. The Method illustrates the ability to resolve structurally similar Capsaicinoids from a pharmaceutical formulation. Peak Shapes and Efficiencies are excellent for both Peaks. Furthermore, […]

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Carotenoids Analyzed with HPLC – AppNote

Compounds of the Carotenoid Family Retained These compounds are very lipophilic and often have subtle differences in structure. Resolution of these compounds can be difficult with a standard Reversed Phase C8 or C18 Column because of these Similarities. The Cogent C30 Column on the other hand can further differentiate by analyte Shape in addition to […]

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Carotenoids Analyzed with SFC – AppNote

Separation in Super Critical Fluid using a Bidentate C18 Column Cogent TYPE-C Silica™ Stationary Phases with the unique hydrophobic, Silica Hydride Surface and a very wide range of Selectivities, can be used for Supercritical Fluid Chromatography (SFC). In HPLC, Cogent TYPE-C Columns are known to retain many polar compounds in the Aqueous Normal Phase (ANP) […]

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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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Cefprozil E & Z Isomers Analyzed with HPLC – AppNote

LCMS Compatible Method The USP Assay Method for Cefprozil uses a phosphate-based Mobile Phase, which is not compatible with LCMS. In this Method, only Formic Acid is needed in the Mobile Phase. The Method meets the isomer resolution criterion of not less than 2.5 with an average calculated value of 4.4. The tailing factor was […]

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Celecoxib Analyzed with HPLC – AppNote

Impurities Method with Improved Peak Shape Celecoxib is Separated from an Impurity in this simple Gradient Method. The Peak shape obtained for this API shows good Peak Symmetry. In addition, the Method shows good repeatability from run to run. The API Retention time %RSD from five runs was 0.025%. Figure A shows the excellent Precision […]

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Cetirizine Tablet Analyzed with HPLC – AppNote

Efficient and Symmetrical Peak of API from Zyrtec® Tablet This Application Note shows how very Efficient Peaks can be achieved for Cetirizine from a tablet formulation and how the API Peak can be well Retained with excellent Symmetry. Even with ion pairing in Reversed Phase Methods, a Peak with acceptable Efficiency and Symmetry could be […]

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Cetylpyridinium Chloride Analyzed with HPLC – AppNote

Excellent Peak Shape for a Cationic Compound Commonly found in Household Products This Method demonstrates the potential to avoid Peak Tailing or Band Broadening with cationic compounds due to interaction with Silanols on the surface of Reversed Phase Column. Tailing can cause interference with Quantitation of a nearby Peak of interest as well. Since Cetylpyridinium […]

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Chlorhexidine Analyzed with HPLC – AppNote

Rapid, Reliable Assay without Ion Pairing Agents Chlorhexidine contains numerous amine functional groups that can have a detrimental effect on Peak Shape in HPLC. The USP Assay Method uses Triethylamine as an Ion Pairing Agent in the Mobile Phase for this reason. The Method developed in this Application Note uses only Formic Acid as the […]

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Chlorpheniramine Maleate Organic Impurities Analyzed with HPLC – AppNote

Separation demonstrated in real commercial formulation extracts Use of the Cogent Bidentate C8™ Column allows for high resolution baseline separation of six specified impurities of Chlorpheniramine Maleate (Fig. A). Fig. B shows how the method can be applied to a real-world formulation, spiked with the N-oxide impurity to demonstrate resolution from the API peak. Currently, […]

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Ciprofloxacin Analyzed With LCMS – AppNote

Retention with Good Peak Shape for this Polar Compound This Method illustrates how the MS compatible HPLC UV Methods described in various application notes can be successfully adapted for LCMS. The Peak Shape for this polar compound meets the System Suitability specification for the USP Tailing Factor. Peak: Ciprofloxacin 332.1405 m/z (M+H)+ Method Conditions Column: […]

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Ciprofloxacin LC-MS Compatible Assay – AppNote

Antibiotic Tablet Ciprofloxacin has several amine groups and therefore is susceptible to peak tailing in Reversed Phase methods. The USP assay method for Ciprofloxacin tablets uses Triethylamine as an Ion Pair Agent to reduce tailing and in addition, Phosphoric Acid is included in the Mobile Phase. These conditions make the USP method incompatible with MS […]

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Clindamycin Antibiotic Tablet Analyzed with HPLC – AppNote

Separation of API from Excipients  The Stability and Robustness of this Method makes it an excellent choice for QC of this semi-synthetic antibiotic which is structurally related to Lincomycin. The Chromatogram shown below of Clindamycin is from a complex Pharmaceutical Formulation but note the excellent Peak Shape for it and the Separation from the Excipients. […]

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Clopidogrel Analyzed with HPLC – AppNote

LCMS Compatible Separation of API from Degradants Although Clopidogrel, commonly known as Plavix, retains well in Reversed Phase, its Degradants showed low Retention even at high water content. Therefore this Method the compounds are retained on the basis of polarity. This Method uses MS compatible Solvents and provides good Retention and separation between the API […]

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Comparison of 4um vs. 2.2um Columns – Extended AppNote

Easy Method Transfer from 4µm to 2.2µm HPLC Columns. The Bidentate C18™ is an excellent choice for Reversed Phase Applications. In addition to the standard 4µm material, a near UHPLC 2.o™ (2.2um) Phase is also available. These 2.2µm Columns provide inherently superior Efficiency than a larger particle size. Because the same C18 ligand is used […]

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Coricidin HBP Day Tablet Analyzed with HPLC- AppNote

Formulation of Guaifenesin and Dextromethorphan HBr This Method shows the separation of two active ingredients in a formulation of Guaifenesin and Dextromethorphan. Dextromethorphan often exhibits tailing in many HPLC methods, but here an excellent Peak shape is observed. This Method is suitable for routine assay of these compounds in combination formulations. A change in wavelength […]

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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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Cough Syrup Ingredient Analysis with HPLC – AppNote

Separation of Antitussives, Analgesics, Decongestants, and Preservatives Cold and cough formulations may contain a number of components such as antitussives (Dextromethorphan), decongestants (Pseudoephedrine, Guaifenesin), analgesics (Acetaminophen), and preservatives (Methyl Paraben, Propyl Paraben, Benzoic Acid). The method illustrates good separation between a variety of these compounds, also that symmetric Peak shapes can be obtained in each […]

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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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Cyclobenzaprine Retention with an Inverse Gradient – AppNote

ANP Retention of a Hydrophobic Compound  This Application Note shows an example of a hydrophobic analyte retention in Aqueous Normal Phase (ANP / HILIC Like Gradient) HPLC. Although Cyclobenzaprine has a logP of approximately 4.6–4.9, it is well retained with a Symmetrical Peak Shape. Data from two production lots of Columns is shown to illustrate […]

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Cycloserine LCMS Separation of Impurities and Degradants – AppNote

LCMS Separation of Impurities and Degradants While two major impurities observed in this Cycloserine method were not directly identified, several possibilities can be suggested based on their m/z values in the Mass Spectrum and their relationship to the Serine structure. Serine was also identified but in very low abundance and only after the samples were […]

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