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Primesep 100 separates a mixture of dicarboxylic acids in ion-exclusion mode with a mobile phase of water, acetonitrile (MeCN, ACN), and sulfuric acid (H2SO4) with UV detection at 210 nm. Baseline resolution of fumaric, maleic, malic, and succinic acids is obtained in less than 8 minutes. The separation combines ion-exclusion and reversed-phase mechanisms in one method.
Dicarboxylic Acids Fumaric Acid Maleic Acid Malic Acid Succinic Acid
UV Detection

Primesep 200 retains and separates the organic diacids (malic, succinic, fumaric, and maleic) by a combination hydrophobic, reversed-phase interactions and ion exclusion. The separation uses a mobile phase of water, acetonitrile (MeCN, ACN) and trifluoracetic acid (TFA) with UV detection at 210 nm.
Dicarboxylic Acids Fumaric Acid Maleic Acid Malic Acid Succinic Acid
UV Detection

Primesep B combines a hydrophobic, reversed-phase mechanism with ion exchange to separate the diacids, fumaric, benzoic, phthalic, naphthoic, and maleic acids. Changing the acetonitrile content of the mobile phase reverses the peak order for naphthoic and maleic acids. Primesep B combines reversed-phase and anion-exchange mechanism with a mobile phase of water, acetonitrile (MeCN, ACN) and trifluoracetic acid (TFA) and UV detection at 250 nm.
Benzoic Acid Dicarboxylic Acids Fumaric Acid Maleic Acid Naphthoic Acid Phthalic Acid
UV Detection

Primesep D separates organic acids such as fumaric, benzoic, phthalic, naphthoic, and maleic acids by a mixture of anion exchange and reversed phase. Retention times and elution order can be changed by adjusting the percentage of acetonitrile in the mobile. This can not be done by traditional ion-exchange and ion-exclusion chromatography. The HPLC separation uses a mobile phase of water, acetonitrile (MeCN, ACN) and trifluoroacetic acid (TFA) and UV detection at 250 nm.
Benzoic Acid Fumaric Acid Maleic Acid Naphthoic Acid Phthalic Acid
UV Detection

Hydrophilic acids are separated on Obelisc N mixed-mode HILIC column. Seven carboxylic acids are separated based on their polarity and pKa values. Changes in ionization states of acids and stationary phase can be used to control elution order of organic and inorganic acids.
Hydroxybenzoic Acid Succinic Acid Mandelic Acid Methylmalonic Acid Malic Acid Fumaric Acid Tartaric Acid
ELSD/MS Detection

Majority of the drugs in pharmaceutical industries are administered in a salt form. The presence of two counter-ions very often requires two methods. The nature of these counterparts in drugs can be: inorganic cation and organic acid, inorganic anion and organic base, and organic cation and organic anion. Based on the property of molecules the stoichiometry can be different also. The task of simultaneous quantitation of counter-ions can be achieved by using mixed-mode columns. The general approach for analysis is based on properties of corresponding counter-ions. Hydrophobic basic drugs, like dextromethorphan, verapamil, trimipramine, and corresponding acidic counter-ions (chloride, chlorate, bromide, bromate, perchlorate, maleate, fumarate,tartrate, succinate, phosphate, citrate, benzosulfonate, toleuensulfonate) can be separated and quantitated in the same run on reversed-phase anion-exchange column. Basic hydrophobic drugs are retained by reversed-phase mechanism, and counter-ion are retained by reversed-phase and anion-exchange mechanism. Some polar counter-ions are retained only by anion-exchange mechanism. Retention time and selectivity of HPLC separation of drugs and counter-ions can be achieved by changing amount of acetonitrile and amount of ions in the mobile phase. Detection technique depends on the properties of counter-ions. In case of low or no UV activity, ELSD can be employed if counter-ion forms non-volatile salt wit mobile phase additive (ammonium formate). This HPLC method can be used for simultaneous quantitation of other basic drugs and counter-ions. Presence of two mechanisms of retention allows to control retention times of drug and counter-ion independently, and even change order of elution when necessary.
Citric Acid Bromide Chloride Chlorate Perchlorate Maleic Acid Fumaric Acid Tartaric Acid Succinic Acid Phosphoric Acid Dextromethorphan Verapamil Pyrilamine Benzenesulfonic Acid p-Toluenesulfonic Acid (PTSA)
UV Detection ELSD/MS Detection
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