|Molecular Weight||118.088 g/mol|
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.
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.
Ascorbic, methylmalonic and succinic are weak organic acids. Retention of these three acids is achieved on Primesep N column in HILIC mode using acetonitrile/water and ammonium acetate. Compounds are monitored by ELSD. Method can be used for determination of ascorbic acid (Vitamin C), methylmalonic acid and succinic acid in various matrices. Other polar organic acids can be analyzed on this HILIC column.
Organic and inorganic acids can be separated by reversed-phase anion-exchange Primesep D column. Succinic and methylmalonic acids were separated based on their hydrophobic and ionic properties. Method can be used for analysis of other acids by HPLC.
Succinic acid is a dicarboxylic acid that plays important role in citric acid cycle. Succinic acid is byproduct of sugar fermentation, and is present in wines and beer. In one of the forms it exists as a salt with sodium. Both sodium and succinic acid can be retained and separated on Primesep 100 column. Sodium is retained by cation-exchange mechanism, while succinic acid is separated by reverse phase mechanism. Method can be used for HPLC analysis of metal ions (sodium, potassium, lithium, calcium, etc) and carboxylic acids (hydrophobic carboxylic mono and diacids) in one chromatographic run. ELSD is detection of choice for non-UV active non-volatile compounds.
In mixed-mode HILIC chromatography, selectivity of separation can be adjusted by amount of acetonitrile, amount of buffer and buffer pH. Buffer concentration and pH will affect retention of ionizable compounds to a different degree. Retention of neutral compounds can be adjusted by the amount of acetonitrile. Carboxylic acid, three amino acids and two sugars are separated by combination of HILIC and ion-exchange mechanisms. Compounds can be monitored by ELSD, Corona (CAD), LC/MS or low UV. UV-transparent mobile phase /buffer is required for UV monitoring of this mixed-mode separation. This HPLC method can be adopted as general approach for analysis of sugars, amino acids and carboxylic acids.
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.
Organic and inorganic acids can be retained and separated on mixed-mode columns based on weak reversed-phase and weak/medium anion-exchange mechanisms. Amount of ACN, buffer concentration and buffer pH will affect retention time of organic and inorganic acids. Acids can be monitored by low UV, ELSD or LC/MS. Presence of ions is required to facilitate ion-exchange mechanism. Method can be used as a general approach for analysis of acidic hydrophilic and acidic hydrophobic compounds. Carboxylic acids along with inorganic acid can be retained and separated without ion-pairing reagent.
This is an alternative approach for the separation of the TCA cycle intermediates that was developed using novel hydrogen-bonding HPLC column. The organic nature of the mobile phase helps obtain a highly sensitive LC/MS compatible method.
The citric acid cycle (tricarboxylic acid cycle, Krebs cycle) is a key process in the metabolic pathway by which all aerobic organisms generate energy. Compounds generated during TCA are hydrophilic, acidic compounds. Some of the hydrophilic acids are very strong while others are relatively weaker. All compounds have very low hydrophobicity and do not retain by the reversed-phase mechanism on the C18 or C8 HPLC columns. Citric acid and related products were separated in reversed-phase, anion-exchange mode on the Primesep D mixed-mode column. All hydrophilic, acidic compounds are well separated and demonstrate good shape. This robust method can be used for analysis of components of the TCA cycle and other highly hydrophilic compounds. This method is fully compatible with LC/MS and prep chromatography.