Benzylamine

Mixed-mode HPLC columns allow to analyze compounds with drastically different properties in one run. Acidic, basic, and neutral compounds can be separated in one run using either isocratic or gradient conditions. In this application, neutral hydrophilic (uracil, phenol and hydroquinone), neutral hydrophobic (toluene), hydrophilic acidic (benzoic acid), hydrophilic basic (lutidine) and hydrophobic basic (amitriptyline) are separated using gradient of ACN. Neutral compounds are retained by reversed-phase mechanism, hydrophilic acidic compound become more hydrophobic at lower pH and retain by reversed-phase mechanism too. Basic compounds are retained by cation exchange mechanism, and hydrophobic basic compounds are retained by reversed-phase and cation-exchange mechanisms. All compounds are resolved within 17 minutes on a short column. Method can be applied to various polar and hydrophobic compounds, which can be separated on one column and in one run. Mixed-mode columns can operate in single or combination of several modes: reversed-phase, ion-exchange, ion-exclusion and HILIC. This mixed-mode HPLC column can be used as a general column for separation of wide range of compounds.

Primesep 100 and Primesep 200 columns can be used as a universal column for analysis of wide range of compounds. These mixed-mode reversed-phase ion-exchange HPLC columns can provide a valuable alternative to traditional reversed-phase column. Amines, amino acids, quaternary amines, and various zwitter-ions can be analyzed along with hydrophobic compounds and organic and inorganic counter-ions. In this application, 8 compounds with different hydrophobic, hydrophilic, basic and acidic properties are separated based on their properties. Primesep 100 column is a mixed-mode HPLC column with a C12 carbon chain and carboxylic acid on the surface with pKa of 1. Primesep 200 column is a mixed-mode HPLC column with a C12 carbon chain and carboxylic acid on the surface with pKa of 2. These columns can be used with 100% organic (ACN) and 100% aqueous mobile phases. This HPLC method can be adopted as a generic and robust approach for analysis of acidic, basic and neutral compounds within the same run.

Primesep mixed-mode columns are designed to separate basic, acidic, neutral and zwitter-ionic compounds. Elution of these compounds is facilitated by acetonitrile and ions in the mobile phase. In all cases the retention time on mixed-mode columns is significantly longer than on traditional reverse-phase columns. Presence of cation-exchange mechanism in Primesep 100 column allows to achieve better retention and peak shape for analytes like phenylalanine and benzylamine. Various buffers can be used along with different detection techniques. This HPLC method can be adopted as a universal approach for analysis of basic, acidic and zwitter-ionic compounds in complex mixtures and formulations. Compounds can be monitored by UV, ELSD, CAD and LC/MS.

This application shows the effect of mobile phase composition on retention of acidic, basic and neutral compound. Retention of basic and acidic compounds is controlled by buffer pH and concentration, while retention of neutral compound is controlled by the amount of acetonitrile. Buffer pH changes not only ionization state of ionizable basic and acidic compounds, but ionization state of trimodal stationary phase Obelisc R. Available detection techniques include UV, ELSD, LC/MS, and Corona.

Separating basic, acidic and zwitterionic compounds in one run in reverse-phase HPLC can be very challenging. The methods might require the use of ion-pairing reagents and complex gradients that can make MS-compatibility difficult. Obelisc R column which has both positive and negative ion-pairs embedded in the stationary phase allows for fine tuning and separation of a wide range of compounds with different ionic properties. Acids, bases, amino acids and neutral compounds were separated isocratically in one run using a simple MS-compatible mobile phase of acetonitrile (ACN) and water with Ammonium Acetate (AmAc) buffer. Can also be UV detected at 250nm.

Primesep 100 separates a mixture of amino acids (tyrosine, phenylalanine), organic acids (benzoic acid, mandelic acid), amines (benzylamine, pyridine), and neutrals (benzonitrile, toluene) in one HPLC run by combining reversed-phase, cation-exchange, and polar interactions. The method is tunable and peak order can be changed significantly by adjusting acetonitrile and trifluoroacetic acid concentrations. The separation method uses a mobile phase mixture of water, acetonitrile (MeCN, ACN) and trifluoracetic acid (TFA) and compatible with UV, mass spec (LC/MS) and evaporative light scattering (ELSD) detection.

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 C demonstrates the control of ion-exchange properties of Primesep columns. The peak order of caffeine and benzylamine in a mixture of caffeine, benzylamine, and phenol reverses when the mobile phase modifier is changed from ammonium acetate to trifluoroacetic acid. Control of the separation is possible even with mass spec (LC/MS) compatible mobile phases of water, acetonitrile (MeCN, ACN) and ammonium acetate or trifluoroacetic acid (TFA).

Primesep C separates benzylamines with an easily tunable HPLC method that allows retention control. Benzylamine, N-methylbenzylamine, and N,N-dimethylbenzylamine peak order and retention can be significantly changed by altering the water/acetonitrile ratio in the mobile phase which changes the combination of cation exchange, complex formation, and hydrophobic interactions. This mixture is separated with a mobile phase of water, acetonitrile (MeCN, ACN) and triethylamine (TEA) phosphate with UV detection at 210 nm.