Category Archives: Separations

HPLC Separation of Phenacetin, Salicylic Acid, Nicotine, Methylamphetamine, and Phenobarbatuic Acid

The graph shown below is a plot of retention time vs. pH for the reverse-phase HPLC separation of a mixture containing phenacetin, salicylic acid, nicotine, methylamphetamine, and phenobarbituic acid. Based on the structures of these compounds and their pKa values, … Continue reading

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Separation of Amino Acids

In ion-exchange chromatography, a solution containing a mixture of compounds is passed through a column packed with a resin containing covalently attached anionic and/or cationic functional groups. One use of ion-exchange chromatography is the separation of compounds based on differences … Continue reading

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Separating a Weakly Acidic Analyte from a Weakly Basic Interferent

Imagine¬† you have an aqueous sample containing a weak acid analyte, HA, and a weak base interferent, HI.¬† The following information about HA, HI, the method of analysis, and the sample are available to you: Ka,HA = 1.00 x 10-3 … Continue reading

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