Maleic Acid

Separation type: Liquid Chromatography Mixed-mode

EDTA Standards Solution A:
For the preparation of the EDTA standard solution, 5 mg of EDTA was accurately weighed and transferred into a 5 mL volumetric flask and dissolved in 0.001N NaOH water solution with sonication or magnetic stirrer mixing. Filtered The EDTA stock solution (1.0 mg/mL) should be stored in a cold dark place and can be used for a week to prepare standards of required concentration.

Iron(III) chloride Solution B:
The standard stock solution of Iron(III) chloride (10 mg/ml) was prepared in water. 50 mg of FeCl3 was accurately weighed and transferred into a 5 mL volumetric flask and dissolved in water, with sonication if needed.

General procedure for Ferric EDTA complex analysis:
To make a sample for analysis mix 100 µL Solution A (or unknown sample) with 100 µL Solution B and 800 µL of water.  Place this mixture in a plastic HPLC vial for analysis. Setup instrument and column according to the method provided.

High Performance Liquid Chromatography (HPLC) Method for Analysis of EDTA and Maleic Acid

New more reliable method for EDTA analysis is available

Separation type: Bridge Ion Separation Technology, or BIST™ by SIELC Technologies

High Performance Liquid Chromatography (HPLC) Method for Analysis of  Maleic  acid, Ascorbic acid, Nicotinic acid, Fumaric acid and Oxalic acid

The maleate ion from Maleic acid is a popular ingredient as the maleate salt in several different drugs, including Methergine, Pyrilamine, and Carfenazine, among others. Nicotinic acid, also known as Niacin or Vitamin B3, is an essential nutrient for the human body and is sometimes taken as a treatment for high cholesterol. Aconitic acid is a key intermediary in the citric acid cycle, and is also used a flavoring agent and in the production of rubbers and plastics. Fumaric acid is a popular preservative and food additive with a fruit-like taste. Using SIELC’s newly introduced BIST™ method, a mixture of these organic acids can be separated on a negatively-charged, cation-exchange BIST™ A+ column, contrary to conventional chromatographic wisdom. There are two keys to this retention method: 1) a multi-charged, positive buffer, such as N,N,N’,N’-Tetramethyl-1,3-propanediamine (TMDAP), which acts as a bridge, linking the negatively-charged anion analytes to the negatively-charged column surface and 2) a mobile phase consisting mostly of organic solvent (such as MeCN) to minimize the formation of a solvation layer around the charged analytes. Other positively-charged buffers that can generate BIST™ include Calcium acetate and Magnesium acetate. Using this new and unique analysis method, these organic acids can be separated, retained, and detected through ELSD. This method is also compatible with Mass Spectrometry (LC-MS) and CAD.

Condition

Description

Separation type: Bridge Ion Separation Technology, or BIST™ by SIELC Technologies

The maleate ion from Maleic acid is a popular ingredient as the maleate salt in several different drugs, including Methergine, Pyrilamine, and Carfenazine, among others. Nicotinic acid, also known as Niacin or Vitamin B3, is an essential nutrient for the human body and is sometimes taken as a treatment for high cholesterol. Aconitic acid is a key intermediary in the citric acid cycle, and is also used a flavoring agent and in the production of rubbers and plastics. Fumaric acid is a popular preservative and food additive with a fruit-like taste. Using SIELC’s newly introduced BIST™ method, a mixture of these organic acids can be separated on a negatively-charged, cation-exchange BIST™ A+ column, contrary to conventional chromatographic wisdom. There are two keys to this retention method: 1) a multi-charged, positive buffer, such as N,N,N’,N’-Tetramethyl-1,3-propanediamine (TMDAP), which acts as a bridge, linking the negatively-charged anion analytes to the negatively-charged column surface and 2) a mobile phase consisting mostly of organic solvent (such as MeCN) to minimize the formation of a solvation layer around the charged analytes.

Condition

Description

Separation type: Liquid Chromatography Mixed-mode

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Ethylenediaminetetraacetic acid (EDTA) is a very common chelating agent, used particularly for collecting Iron and Calcium ions. It has a wide range of applications, including in the textile industry, paper industry, pharmaceutical industry, and in cosmetics, where it is used to capture unwanted metal ions in solution. Maleic acid, a dicarboxylic acid, has a few interesting applications, such in medicine to form salts with drugs to increase their stability and as a precursor for the production of glyoxylic acid, which is used in cosmetics. An Iron (III)-EDTA complex and Maleic acid can both be retained, separated, and analyzed on a mixed-mode Newcrom BH column with a mobile phase consisting of (mostly) water, Acetonitrile (MeCN), and Perchloric acid (HClO4). This analytical method can be UV detected at 220 nm with high resolution and peak symmetry.

High Performance Liquid Chromatography (HPLC) Method for Analysis of EDTA and  Maleic Acid

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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.

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.

Application Notes: Maleic acid is a small hydrophilic acid, which is poorly retained in reversed-phase chromatography. Pentaerythritol is hydrophilic neutral molecule. A miixed-mode HILIC/anion-exchange method was developed on Obelisc N HPLC column. The retention time for maleic acid can be controlled by amount of ACN, buffer pH, and buffer concentration. Pentaerythritol retention time is only controlled by the amount of acetonitrile. The method is LC/MS and ELSD compatible.
Application Columns: Obelisc N
Application compounds: Maleic Acid, Pentaerythritol
Detection technique: LC/MS, ELSD/CAD 

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.

Mixture of polar acidic and basic compounds is separated on a Primesep AB mixed-mode HPLC column. Dopamine and tyrosine are retained by combination of reversed-phase and cation-exchange mechanisms. Maleic acid is retained by anion-exchange mechanism, and benzoic acid is retained by reversed-phase mechanism. Primesep AB is a trimodal column with a C12 hydrophobic chain and cation-exchange and anion exchange groups on the surface. Method utilizes UV detection but can be used with other detection techniques (ELSD, LC/MS, Corona).

The majority of drugs in the pharmaceutical industry are administered in salt form. The presence of two counter-ions very often necessitates the use of two methods. The nature of these counterparts in drugs can be an inorganic cation and organic acid, inorganic anion and organic base, and organic cation and organic anion. Furthermore, the properties of the molecules will result in a differing stoichiometry. 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 the reversed-phase mechanism, and counter-ions are retained by the reversed-phase and anion-exchange mechanism. Some polar counter-ions are retained only by the anion-exchange mechanism. Retention time and selectivity of HPLC separation of drugs and counter-ions can be achieved by changing the amount of acetonitrile and the amount of ions in the mobile phase. The detection technique depends on the properties of the counter-ions. In case of low or no UV activity, ELSD can be employed if the counter-ion forms a non-volatile salt with the mobile phase additive (ammonium formate). This HPLC method can be used for simultaneous quantitation of other basic drugs and counter-ions. The presence of two mechanisms of retention allows control over retention times of drug and counter-ion independently, and even allows a change of order of elution when necessary.

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.

Primesep B separates acids, bases, and neutrals in one injection. Maleic acid, benzonitrile, and benzylamine are baseline resolved by a combination of reversed-phase, ion-exchange, and ion-exclusion mechanisms. Excellent peak shape results with a mass spec compatible mobile phase of water, acetonitrile (MeCN, ACN) and trifluoracetic acid (TFA) with UV detection at 210 nm.

Primesep A separates acids, bases, and neutrals in one injection. Maleic acid, benzonitrile, and benzylamine are baseline resolved by a combination of reversed-phase, ion-exchange, and ion-exclusion mechanisms. Excellent peak shape results with a mass spec compatible mobile phase of water, acetonitrile (MeCN, ACN) and trifluoracetic acid (TFA) with UV detection at 210 nm.

Primesep 100 retains and separates an acid, base, and neutral in one HPLC injection. Maleic acid, benzylamine, and benzonitrile are resolved by ion-exclusion, ion-exhange and reversed-phase modes. The separation uses a mobile phase of water, acetonitrile (MeCN, ACN) and trifluoracetic acid (TFA) with UV detection at 210 nm.

Primesep 200 separates acids, bases, and neutrals in one injection. Maleic acid, benzonitrile, and benzylamine are baseline resolved by a combination of reversed-phase, ion-exchange, and ion-exclusion mechanisms. Excellent peak shape results with a mass spec compatible mobile phase of water, acetonitrile (MeCN, ACN) and trifluoracetic acid (TFA) with UV detection at 210 nm.

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.

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.

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.