Diphenhydramine HCL Capsule Analyzed with HPLC – AppNote

Assay Method for Diphenhydramine HCL without Ion Pairing Agents Diphenhydramine has a tertiary amine functional group that can produce tailing with conventional Columns in Reversed Phase HPLC. The USP Method features a Triethylamine additive in the Mobile Phase for this reason. These additives often take a significant time to completely load onto the Column and […]

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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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L-a-phenylglycine Antibiotic Analysis with HPLC – AppNote

Comparison using Cogent Silica-C™ and UDC-Cholesterol™ HPLC Columns In this Method, a non-modified, silica-hydride HPLC Column, Cogent Silica-C, produces good Retention of the important amino acid L(+)-α-Phenylglycine with an Isocratic Mobile Phase. In addition the Retention Times are extremely Reproducible (%RSD 0.2). The same Method using a Cogent UDC-Cholesterol Column (UDC), silica-hydride with an 11 […]

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Nonylphenol Analyzed with HPLC – AppNote

Separation of Isomer Peaks Nonylphenol is a very hydrophobic compound and is suitable for analysis by Normal Phase. It is produced commercially by Acid-catalyzed Alkylation of Phenol with a mixture of nonenes. Therefore a variety of product isomers are possible, with different branching of the C9 group and position of the chain on the ring. […]

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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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Phenylglycine & Phenylalanine Analyzed with HPLC – AppNote

Analysis using a Simple Mobile Phase. In this Method two important amino acids: L-(+)–alpha-phenylglycine and L-phenylalanine, were Separated. C18 Columns used today which may be present in every Analytical Laboratory may not be able to Retain underivatized Amino Acids. They usually elute at or near the “void volume” with other polar compounds. Peaks: 1. L-(+)-Alpha-Phenylglycine […]

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