Maleic acid
Column: | Amaze HA |
Separation Modes: | reveresed-phase , anion-exchange |
Column Dimenstions: | 4.6x100, 3 um, 100A |
Mobile Phase: | "A: 2% ACN with 40 mM ammonium phosphate pH 4.0 B: 20% ACN with 100 mM ammonium phosphate pH 2.0 gradient from 100% A to 100% B in 15 minutes, 5 minutes hold " |
Detection: | 205 nm |
Sample: | 0.2-0.5 mg/ml |
Injection: | 2 uL |
Flow rate: | 1 ml/min |
Class of compounds: | Aromatic acid, Isomer, Organic acid, Organic compound, Preservative, Supplement, Vitamin |
Nature of compounds: | Acidic, Hydrophilic, Hydrophobic, Neutral, Polar |
Compounds: | Acetic acid, Ascorbic acid, Formic acid, Succinic acid, Citric acid, Malonic acid, Fumaric acid, Mandelic acid, Oxalic acid, Terephthalic acid, Benzoic acid, Maleic acid, Phthalic acid, Benzenesulfonic acid, p-Toluenesulfonic acid |
Column: | Amaze HA |
Separation Modes: | reveresed-phase , anion-exchange |
Column Dimenstions: | 4.6x100, 3 um, 100A |
Mobile Phase: | ACN/water/phosphoric acid and ACN/water/ammonium phosphate buffer |
Detection: | 205 nm |
Sample: | 0.2-0.5 mg/ml |
Injection: | 2 uL |
Flow rate: | 1 ml/min |
Class of compounds: | Organic acid, Preservative |
Nature of compounds: | Acidic, Hydrophilic, Polar |
Compounds: | Citric acid, Fumaric acid, Oxalic acid, Maleic acid, Acetic acid, Formic acid |
There are several groups of compounds which are used as active and inactive ingredients in various over-the-counter drug compositions. These compounds are different in nature and can be organic and inorganic. Most of the active ingredients are either hydrophobic basic, hydrophilic basic or hydrophilic neutral compounds. Basic active ingredients of cough and cold remedies used as salts of organic and inorganic acids. The most commonly used hydrophobic active ingredients are doxylamine, pyrilamine, chlorpheniramine, brompheniramine, and dextromethorphan. Doxylamine is an antihistamine drug, used to relieve symptoms of allergy, hay fever, and the common cold. Doxylamine is used in combination with other active ingredients to provide effective nighttime relief from cough and cold symptoms. Pyrilamine is an antihistamine drug, which targetsH1 receptors as an inverse agonist. Brompheniramine is an antihistamine drug of propylamine nature. Chlorpheniramine is an antihistamine used to treat symptoms such as allergic rhinitis. Dextromethorphan is a medication mostly used as a cough suppressant. It is a morphine type of medication with sedative, dissociative, and stimulant properties. Succinic acid is a hydrophilic diacid that is used as a counterion. Maleic acid is hydrophilic diacid which is used as a counterion. Both compounds have very limited retention even in RP-AQ columns. Due to the strongly hydrophobic and basic properties of these compounds, they demonstrate a poor peak shape in traditional reversed-phase chromatography due to the overloading of residual silanol groups on the surface when these basic drugs are analyzed. In addition to this, hydrophilic counterions are not retained in RP because there is no mechanism of retention for these acidic hydrophilic compounds. Both problems were eliminated by using Heritage MA reversed-phase anion-exchange column. Column and method demonstrate high efficiency and good peak shape for acidic and basic analytes. It can be used to develop methods for various cough, cold, and congestion compositions without the use of ion-pairing reagents. Compounds are well retained by a combination of one or more mechanisms. The column is compatible with 100% ACN and 100% water as well as with most buffers with pH 1.5-7. Various additives to the mobile phase can be used based on the nature of samples and detection techniques.
Column: | Heritage MA |
Separation Modes: | reversed-phase, cation-exclusion, anion-exchange |
Column Dimenstions: | 4.6x150 mm, 3 um, 100A |
Mobile Phase: | 5% ACN with 30 mM AmFm pH 3 |
Detection: | UV 275 |
Sample: | various |
Injection: | 3 uL |
Flow rate: | 1 ml/min |
Class of compounds: | Amines, Aromatic base, Drug, Organic acid, Pyridine |
Nature of compounds: | Acidic, Basic, Hydrophilic, Hydrophobic, Polar |
Compounds: | Doxylamine, Pyrilamine, Succinic acid, Chlorpheniramine, Brompheniramine, Maleic acid, Dextromethorphan |
The analysis of drugs and counterions usually requires two methods; one for the drug and another one for the counter-ion. This is true for basic and acidic drugs, as well as basic and acidic counter-ions. Brompheniramine is an antihistamine drug used in many cough and cold formulations (Nyquil, Avil, Dimetapp, Vick’s, etc). Brompheniramine is hydrophobic and basic in nature. Reversed-phase chromatography usually produces poor peak shape for this highly hydrophobic and basic compound due to the overloading of residual silanols on the surface of silica gel. Maleic acid is a common counter-ion used in drug production and various formulations. It has two carboxylic acid fragments with pKa of 1.94 and 6.22. It is very polar in nature due to the presence of two ionizable groups. We have developed a separation approach for analysis of basic drug and acidic counter-ion. The order of elution for brompheniramine and maleic acid can be changed by changing the amount of ACN, buffer pH and buffer concentration. The Heritage MA is a mixed-mode anion-exchange and cation-exclusion column. The basic ionizable group on the surface of silica gel shields silanols from interacting with the basic group in bromnehiramine, thus producing a perfect peak shape. The method is LC/MS compatible and no ion-pairing reagent is required to retain basic drug or acidic counter-ion retention time. The elution on the Heritage MA column is controlled by the amount of ACN, buffer concentration and buffer pH. The buffer pH, concentration control ion-exchange, ion-exclusion mechanisms and amount of ACN are controlling the hydrophobic retention of compounds analyzed on this mixed-mode column
Column: | Heritage MA |
Separation Modes: | reversed-phase, cation-exclusion, anion-exchange |
Column Dimenstions: | 4.6 x 150 mm, 5 um, 100A |
Mobile Phase: | ACN/water/ammonium formate |
Detection: | UV 255 nm |
Sample: | 0.3 mg/ml |
Injection: | 3 uL |
Flow rate: | 1 ml/min |
Class of compounds: | Aromatic base, Drug, Organic acid |
Nature of compounds: | Acidic, Basic, Hydrophilic, Hydrophobic, Polar |
Compounds: | Brompheniramine, Maleic acid |
Column: | Heritage MA |
Separation Modes: | reveresed-phase, anion-exchange |
Column Dimenstions: | 4.6 x 150 mm, 5 um, 100A |
Mobile Phase: | 35% ACN with 50 mM AmFm pH 3 |
Detection: | UV 255 nm |
Sample: | 0.2 mg/ml |
Injection: | 5 uL |
Flow rate: | 1 ml/min |
Class of compounds: | Aromatic acid, Organic acid, Preservative |
Nature of compounds: | Acidic, Hydrophilic, Hydrophobic, Polar |
Compounds: | Gallic acid, 4-Hydroxybenzoic acid, Caffeic acid, Mandelic acid, Maleic acid, Atrolactic acid |
Mixture of hydrophilic acidic compounds are separated in reversed-phase anion-exchange mode on core-shell mixed-mode column. Method is robust, reliable and fast and can be used for analysis of underivatized acids without ion-pairing reagent.
Column: | Coresep SB |
Separation Modes: | reversed-phase and anion-exchange |
Column Dimenstions: | 3.2 x 100 mm, 2.7 um, 90A |
Mobile Phase: | 50% ACN with 50 mM sodium phosphate (monobasic) pH 3 |
Detection: | UV 230 nm |
Sample: | 0.3 mg/ml |
Injection: | 3 uL |
Flow rate: | 0.5 mg/ml |
Class of compounds: | Aromatic acid, Organic acid |
Nature of compounds: | Acidic, Hydrophilic, Polar |
Compounds: | Benzoic acid, Maleic acid, Fumaric acid |