Levothyroxine Analysis – AppNote

Superior Resolution, Reproducibility, & Peak Shapes Compared to USP Method The USP assay method for Levothyroxine requires that a resolution of not less than 5.0 must be demonstrated between Levothyroxine and related compound Liothyronine. A chromatogram obtained from following the USP method using a Type-B Silica based L10 Column is shown in Figure B. The […]

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Lidocaine in Gel Analyzed with HPLC – AppNote

Assay Method for Solarcaine® Gel Extract This AppNote shows how Lidocaine Hydrochloride (HCL) from a gel extract can be easily analyzed. The compound has a tertiary amine but excellent Peak shape is achieved; which is often difficult to obtain for analytes like this. A Gradient was used to ensure components from the gel extract matrix […]

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Lisinopril Analysis with HPLC – AppNote

Retention and Peak Shape for Highly Polar Compound As a highly hydrophilic compound, Lisinopril is not well-suited to Reversed Phase Methods. The USP assay method for Lisinopril uses a highly Aqueous Mobile Phase (96% 2.76 g / L Monobasic Sodium Phosphate adjusted to pH 5.0 / 4% Acetonitrile) in Reversed Phase with an L7 Column. […]

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LSD and Codeine – AppNote

LCMS Method for Spiked Urine Sample LSD and codeine may be present in Urine samples and methods are needed for their detection in these matrices. The extracted Ion Chromatograms (EICs) for both analytes are shown in the figure and illustrate excellent chromatographic as well as Mass Spectral Separation. The Method in this AppNote produces high […]

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Meloxicam Tablet Analyzed with HPLC – AppNote

Rapid, Reliable Isocratic Method for this API The USP Assay Monograph Method for Meloxicam uses a phosphate based Mobile Phase. In this application note, a 0.1% Formic Acid additive is chosen in lieu of phosphates in order to be LCMS compatible. The System Suitability requirement is not more than 2.0 for Tailing factor. Highly Symmetrical […]

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Meprobamate Analysis by LCMS – AppNote

Rapid & Simple Analysis of Meprobamate. One Step Sample Preparation with Plasma or Urine Several methods have been reported in the literature for the quantification of Meprobamate in biological samples (plasma, urine, hair etc) for patient monitoring and other tests. Most of these methods present the drawbacks of long analysis time and complex sample pre-treatment […]

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Method Transfer for Cyclobenzaprine – AppNote

Increased Efficiency: 4 μm to 2.2 μm The two chromatograms compare the retention and efficiency of a Cyclobenzaprine peak using two types of Cogent Diamond Hydride Columns. Figure A uses a near-UHPLC 2.2 µm phase while Figure B uses a standard 4 µm particle size column. The results show consistent retention between the two phases […]

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Methotrexate Analyzed with LCMS- AppNote

Methotrexate an Anti-Neoplastic and Anti-Tumor Drug The powerful anticancer drug, Methotrexate (4-Amino-N10- Methylpteroyl Glutamic Acid) acts as an antimetabolite and is used for the treatment of many neoplastic diseases including acute leukemia, osteosarcoma, non-Hodgkins lymphoma, and breast cancer. There is a great interest in pharmacological studies and clinical monitoring of Methotrexate. A quadrupole Mass Spectrometer […]

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Metoprolol Tartrate Analyzed with HPLC – AppNote

Excellent Peak Shape for an Organic Amine This Assay is easy to perform with a well-retained analyte Peak. Since Peak Tailing can often be an issue with organic amines, such as this compound, using conventional HPLC Columns it is notable that this Method produces a very Symmetrical Peak. In the Chromatogram below, an overlay of […]

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Metronidazole Topical Cream Analyzed with HPLC – AppNote

Retention for Highly Polar API This API has very little Hydrophobic character and is not readily retained by Reversed Phase. The Peak that was obtained had excellent efficiency and symmetry. Three runs are shown in the figure in order to illustrate the repeatability of the data. Peak: Metronidazole Method Conditions Column: Cogent Diamond Hydride™, 4µm, […]

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Mometasone Furoate in Topical Cream Analyzed with HPLC – AppNote

Separation of Prodrug from Acid Hydrolysis Products This Method shows the Separation of an ester Prodrug, Mometasone Furoate, from another compound formed during acid hydrolysis. This Peak is quite possibly the active form, Mometasone. The two Chromatograms show the non-degraded extract (Figure A) and an acid hydrolysis extract (Figure B). Hydrolysis of the ester group […]

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Morphine Sulfate Tablet Analyzed with HPLC- AppNote

Excellent Peak Shape for Tertiary Amine Morphine can be a very problematic compound for analysis with HPLC. It has a tertiary amine and has a tendency to tail under some conditions. USP assay methodology uses phosphates, alkylsulfonates, or other LC-MS incompatible agents in the Mobile Phase. This Method uses only Formic Acid and can be […]

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Morphine, Hydromorphone and 6-MAM in Plasma Analyzed with LCMS – AppNote

Morphine, Hydromorphone and 6-Monoacetylmorphine (6-MAM) in Plasma This AppNote presents a Method that could be used for a routine analysis of Plasma Samples or (whole blood samples after changing the extraction procedure) for the presence of Morphine, Hydromorphone (isobaric compounds) or 6-MAM (an indicator of Heroin use). Peaks: 1. Morphine 286.1438 m/z [M+H]+ 2. Hydromorphone […]

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Neomycin Sulfate Analyzed with LCMS – AppNote

Neomycin presents a number of challenges to routine Chromatographic Analysis. It lacks Chromophores and therefore is difficult to detect using conventional HPLC techniques and retention in traditional Reversed Phase mode may not be viable due to its high polarity.  However, use of the Cogent Diamond Hydride Column in conjunction with a Mass Spec helps circumvent […]

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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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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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Ocella® Tablet Analyzed with HPLC – AppNote

Separation of Drospirenone and Ethinyl Estradiol Good Selectivity with high Efficiency Peaks can be achieved analyzing Ocella Tablets. This can be helpful since Ethinyl Estradiol is present at a much lower concentration than Drospirenone and therefore can be difficult to detect; the high Efficiency can contribute to a stronger Signal in detection thus increasing Sensitivity. […]

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Octreotide Analyzed with LCMS – AppNote

Retained Isocratically or With a Gradient This cyclic Octapeptide can be retained with simple Isocratic Mobile Phase conditions of 50:50 Solvent A / Solvent B (see Figure I). In addition, use of a Gradient produces a sharper Peak if desired (Figure II). Note, that the Gradient starts at an unusually high percent of Water (50%) […]

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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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Orthogonal HPLC Method Development – AppNote

Choose Reversed or Normal Phase Selectivity on the Same C18 Column In the Chromatogram (A) below, a Reversed Phase Method Strategy is used: Loratadine in 100% Tetrahydrofuran (THF) elutes with the Solvent Front. With 70:30 DI Water / Tetrahydrofuran (THF), the Selectivity for this Compound is Reversed Phase, which is based on polarity of the […]

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Oxybenzone and Octinoxate Analyzed with HPLC – AppNote

Separation of Two APIs in Chap Stick® Extract This Method shows how two common ingredients found in sunscreens and lip balms can be separated. The two compounds are very hydrophobic, so a Mobile Phase Gradient with significant organic content was used in order to avoid excessive retention. Likewise, a highly organic diluent should be used […]

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Oxymetazoline HCL Analyzed with HPLC – AppNote

Polar API Separated from a Matrix Peak Oxymetazoline can be difficult to obtain a good Peak Shape with conventional HPLC Methods, and the USP System Suitability requires that the Tailing Factor be not more than 2.0. Also, the USP Method calls for a Cation Exchange (L9) Column for the Assay. This Method produces excellent Peak […]

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Paracetamol, Aspirin and Salicylic Acid HPLC Method – AppNote

Analgesic Drugs Analyzed with HPLC A robust and rapid method was developed for the accurate simultaneous determination of Paracetamol, Aspirin, Caffeine, Benzoic Acid as an internal standard and Salicylic Acid (hydrolysis product of Aspirin). This method is rapid and sensitive and therefore suitable for routine quality control of these drugs in dosage forms and for […]

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Pepto-Bismol® Tablet Method Transfer with HPLC – AppNote

A Simple Assay Method for the widely used Pepto-Bismol® Formulation Excellent Separation of Bismuth Subsalicylate and Salicylic Acid is achieved showing that this Method can be readily transferred to a near-UHPLC 2.o phase (Figure A) from a standard 4μm Column (Figure B). The same Column Dimensions are used in both cases, with the only difference […]

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pH Gradient to Separate Vitamins – AppNote

Separation of Ascorbic Acid, Riboflavin, Pyridoxine, & Thiamine This LCMS compatible Method shows excellent Separation and Retention for all four analytes. If the analysis were done by Reversed Phase, LCMS incompatible ion pair agents would likely be required to get this type of separation. Ascorbic Acid was found to have better Retention near neutral pH […]

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Phenolic Compounds Analyzed with Normal Phase HPLC – AppNote

Cogent Silica-C™ Compared to Standard Silica in Normal Phase HPLC The Cogent Silica-C Column was compared with a different brand and type of Silica Column for Separation of three proprietary, large, substituted Phenol Compounds using Normal Phase HPLC . The Cogent Silica-C Column provided satisfactory Selectivity under isocratic elution conditions. The Column displayed typical Normal […]

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Phenylephrine HCL Tablet Analyzed with HPLC – AppNote

Analysis of Phenylephrine, a Highly Polar Compound Phenylephrine was first studied under various Reversed Phase conditions using a C18 Stationary Phase, but even using a 95% Aqueous Mobile Phase a Retention factor of no more than 0.6 could be obtained. With such low retention, it may be difficult to Separate Phenylephrine from excipients or other […]

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Prasugrel Analyzed with HPLC – AppNote

Comparison of Diamond Hydride to C18 HPLC Column Prasugrel has a tertiary Amine and therefore tails in many Reversed Phase methods and conventional HPLC columns. Figure A shows how a sharp and symmetrical peak can be easily obtained with the Cogent Diamond Hydride Column using an MS-compatible Mobile Phase. Figure B shows the peak that […]

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Prednisone Analyzed with HPLC – AppNote

Isocratic Method for Prednisone Tablets  This Method uses the Mobile Phase specified in the USP Method for Assay of Prednisone tablets. The resolution between the API and the Acetanilide Internal Standard meets the system suitability. Resolution was found to be superior compared to standard C18 HPLC Columns. In addition, this Method also produces excellent precision […]

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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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Primatene Tablet Analyzed with HPLC – AppNote

Separation of Guaifenesin and Ephedrine from an OTC Formulation These two compounds are used together in the Primatene® formulation for the purpose of treating Bronchial Asthma. The Separation obtained illustrates the application of this Method in the Analysis of an Over the Counter Formulation. A wavelength change was used in order to make the two […]

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Promethazine Assay & Impurity Analyzed with HPLC – Extended AppNote

Two methods for analysis of Promethazine Tablets address difficulties associated with HPLC for these formulations. The first one discussed is the Assay Method. Here a simple isocratic approach is used and a symmetrical peak shape is obtained for the API. The method meets system suitability criteria in terms of peak area precision, tailing factor, and […]

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Propantheline Bromide HPLC Methods- AppNote

Orthogonal Methods without Ion-Pairing Agents In the USP assay method for Propantheline Bromide tablets, Sodium Dodecyl Sulfate (SDS) is used as an Ion-Pairing Agent in the Mobile Phase. The long alkyl chain of this additive makes it particularly difficult and time consuming to load and remove from the HPLC column. Is this method, not only […]

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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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Pyrantel Pamoate Analyzed With HPLC – AppNote

Robust Separation with Excellent Peak Shapes The USP Assay Method for Pyrantel Pamoate uses a bare Silica Column with a Mobile Phase of Acetonitrile, Acetic Acid, Water and Diethylamine. Bare Silica Columns are often less Robust than Reversed Phase Columns due to the variable nature of the adsorbed water layer and / or the ion […]

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Pyrilamine Maleate Analyzed with HPLC – AppNote

Separation of Pyrilamine with a Simple Isocratic Method Pyrilamine is a challenging compound to analyze with HPLC because it contains several amine groups that can contribute to peak tailing. In this Method, an excellent Peak shape is obtained for Pyrilamine with a simple isocratic Mobile Phase. Data is shown for two lots of Columns in […]

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Ranitidine Tablet Analyzed with HPLC – AppNote

Excellent Peak Shape of API From an OTC Tablet Ranitidine has several amine functional groups that can contribute to significant tailing with Reversed Phase Methods. Data shown below uses an extract from a tablet formulation, illustrating how good Peak shape can be obtained. In addition, three Column lots were used to demonstrate the robustness and […]

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Resveratrol Isomers Found with HPLC – AppNote

Resveratrol Isomers Found in OTC Capsules Two isomers of Resveratrol were observed using this simple Reversed Phase Method. Different capsules were analyzed and it was discovered that some had both isomers while the cis isomer was not detected in others (data not shown). The ability of this Method to Separate two Isomers is a good […]

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Sertraline Tablet Analyzed with HPLC – AppNote

Retention of Hydrophobic and Hydrophilic Analytes with Zoloft® Sertraline has a logP of 2.9, but retains well when using Aqueous Normal Phase (ANP) HPLC. A polar test solute, Phenylglycine, was added to demonstrate how both nonpolar and polar compounds can be retained in the same Method. This would be important when looking for impurities or […]

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Simvastatin Analyzed with HPLC – AppNote

Excellent Peak Shape and Resolution This Method is easy to prepare, use and reproduce. Good Peak shape and Resolution is observed for Simvastatin from its hydrolysis products and tablet Excipients. Peaks: 1. Excipient 2. Hydrolysis Product 3. Simvastatin Method Conditions Column: Cogent Bidentate C18™, 4μm, 100Å Catalog No.: 40018-75P Dimensions: 4.6 x 75mm Mobile Phase: 52% DI Water / […]

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Stability Testing of Tetracycline HCl Capsules – AppNote

Robust, high-throughput Separation of API from its Degradation Products Figure A shows the chromatogram obtained from a single injection of the degraded Tetracycline capsule extract. Tetracycline is well-resolved from its three main degradation products, the identities of which were confirmed by individual standards under non-degrading conditions. Amine-containing analytes such as these often require the use […]

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Streptomycin Analyzed with HPLC – AppNote

Retention of a Highly Polar Antibiotic Streptomycin is very polar and difficult to retain with Reversed Phase methods using conventional Columns. In this Method, retention is achieved with Separation of the Streptomycin from two impurities found in the Standard Solution. Furthermore, the numerous amine groups do not cause tailing of Peak shape as with standard […]

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Sulfisoxazole Acetyl Analyzed with HPLC – AppNote

Separation of two Common Preservatives from the API in a Pharmaceutical Suspension Orally administered suspensions with Sulfisoxazole Acetyl often contain the preservatives Methyl and Propyl Paraben. As such, it is important to separate these compounds from the API in an HPLC Assay Method to properly analyze the suspension. With this Method, excellent Separation is obtained […]

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Sumatriptan as an API Analyzed with LCMS – AppNote

Analysis of Imitrex® API from Tablet Formulations This AppNote Method for Analysis of a challenging compound (Sumatriptan) has several advantages over other Methods. This Analysis can be performed using a higher concentration of organic solvent, which is much more suitable for electrospray MS Detection. This AppNote provides robust and repeatable (%RSD 0.1 and lower) results. […]

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Tapentadol HCl Tablet Analyzed with HPLC – AppNote

Assay Method for the Analgesic Nucynta Tapentadol can be a problematic compound for HPLC analysis due to the Amine functional group. Tertiary amines are often particularly difficult to obtain a good peak shape using Reversed Phase methods. Peak tailing has been reported in several published papers in the literature. With this Method, a sharp Peak […]

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Terbutaline and Salbutamol Analyzed with HPLC – AppNote

Separation of ß2-Adrenergic Receptor Agonists This Method shows how two structurally similar compounds can be readily separated. This is an important characteristic in many types of HPLC Methods since typical separations often involve impurities, degradants, metabolites, and other groups of compounds that have subtle structural differences. These two compounds for instance were found to coelute […]

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Tizanidine HCl HPLC Method Transferred to Near UHPLC – AppNote

Use of Near UHPLC Column for Improved Results This challenging compound has several amine groups and can be problematic to analyze with HPLC. Here a good peak shape is obtained using the Cogent Diamond Hydride 2.o Column. The efficiency is higher on the 2.2µm phase compared to a standard 4µm Column, leading to increased sensitivity. […]

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Tizanidine HCl Tablet Analyzed with HPLC – AppNote

Separation Method for Tizanidine Compatible with LC-MS Tizanidine has numerous amine functional groups and can be a challenge for analysis with HPLC. The USP method uses Phosphate in the Mobile Phase which is not compatible with LC-MS. This Method however uses Formic Acid as the Mobile Phase additive and produces a sharp, symmetrical peak. The […]

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Tizanidine HCl Tablet with Precision – AppNote

Excellent Run to Run Precision Tizanidine has several amine groups which can present problems to chromatographers. Residual silanols on the surface of ordinary Silica-based Columns can electrostatically interact with these groups, causing peak tailing. The Cogent Amide Column, used in the Application Note is virtually free of residual silanols and therefore a symmetrical peak shape […]

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Tobramycin Analyzed with LCMS – AppNote

Retention of Highly Polar, Water Soluble Antibiotic  Tobramycin is a very polar compound that lacks a sufficient chromophore, and therefore is difficult to analyze using Reversed Phase HPLC with UV detection. In this Application Note, the Method below retains Tobramycin and Separates it Uracil which is used as a Solvent Front Marker. Using this Method, […]

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