Separator Aminex

The hydrophobic macroporous polystyrene beads are exceptionally chemically stable and are used for organic phase gel permeation chromatography products, Styragel (Waters) and PLgel (Polymer Laboratories) and reversed phase HPLC separations, PRP (Hamilton) and PLRP-S (Polymer Laboratories). It is possible to surface modify the particle to mask the hydrophobicity of the base polymer and produce ion exchange and hydrophilic materials, PI SAX, PL-GFC (Polymer Laboratories). In the microporous form after derivatisation to form strong cation exchangers these materials are commonly used for carbohydrate and amino acid separations, Aminex (BioRad). 

Palmer showed that F-2DFG prepared from 61 and F2 could be separated, by liquid chromatography on a cation-exchange resin (Aminex-A5, Rb form), from [ F]fluoride and less-polar impurities, but not from F-2DFM. 

Figure 12 Gradient separation of bases, nucleosides and nucleoside mono- and polyphosphates. Column 0.6 x 45 cm. Aminex A-14 (20 3 p) in the chloride form. Eluent 0.1 M 2-methyl-2-amino-l-propanol delivered in a gradient from pH 9.9-100 mM NaCl to pH 10.0-400 mM NaCl. Flow rate 100 ml/hr. Temperature 55°C. Detection UV at 254 nm. Abbreviations (Cyt) cytosine, (Cyd) cytidine, (Ado) adenosine, (Urd) uridine, (Thyd) thymidine, (Ura) uracil, (CMP) cytidine monophosphate, (Gua) guanine, (Guo) guanosine, (Xan) xanthine, (Hyp) hypoxanthine, (Ino) inosine, (Ade) adenosine, (UMP) uridine monophosphate, (CDP) cytidine diphosphate, (AMP) adenosine monophosphate, (GMP) guanosine monophosphate, (IMP) inosine monophosphate, (CTP) cytidine triphosphate, (ADP) adenosine diphosphate, (UDP) uridine monophosphate, (GDP) guanosine diphosphate, (UTP) uridine triphosphate, (ATP) adenosine triphosphate, (GTP), guanosine triphosphate. (Reproduced with permission of Elsevier Science from Floridi, A., Palmerini, C. A., and Fini, C., /. Chromatogr., 138, 203, 1977.)...

HPLC analysis for succinic acid, succinamic acid, succinamide, succinimide, N-methylsuccinimide, butyric acid, and propionic acid was performed with a Waters Model 515 HPLC pump equipped with a Waters Model 2410 Refractive Index Detector. Separations were performed with an Aminex HPX-87H 300mm column (Bio-Rad Laboratories, Hercules, CA) operated at 35°C, and using 0.005 M H2S04 elluent. 

Products were analyzed via Waters Model 515 HPLC Pump fitted with a Waters model 2410 refractive index detector. Separations was performed via an Aminex HP-87H 300mm column at 65°C using 0.005M H2SO4 as the mobile phase. Compounds calibrated for this work included xylitol, arabitol, erythritol, threitol, PG, EG, glycerol, lactate, 1-propanol, 2-propanol, ethanol, methanol, and the butanetriol isomers. Any compounds not visible by RID were not quantified in this work. 

Valproic acid was determined in tablets and plasma using ion-chromatography [29], The extract was injected onto a column (6.5 cm x 6 mm) of Dionex ICE separator resin fitted with a guard column of Aminex cation exchange resin and operated with aq. 0.5 mM C02 as mobile phase (0.7 mL/min) and conductivity detection. For tablets, the calibration graph was rectilinear for 0.2-25 pg/mL with limit of detection of 50 pg/mL. For plasma, the response was linear for 50-200 pg/mL and limit of detection was 2 pg/mL. 

Nondek et al. (46) reported an innovative approach to the analysis of N-methylcarbamates in river water using postcolumn reaction detection. Separation of the underivatized N-methylcarbamates was carried out on a reversed-phase column hooked directly to a bed reactor packed with Aminex A-28, a tetraalkylammonium anion-exchange resin. The packed bed catalytically base-hydrolyzed the carbamates and... 

An example of separation obtained with this method is reported in Fig. 2. Falque and Fernandez (23) study the influence of time of contact with the skins on the composition of the volatile fraction and of the carboxylic acids in wine produced from Treixadura grapes. Also, these authors quantify glycerol and ethanol, besides carboxylic acids and sugars, through the use of an Aminex HPX-87H (300 X 7.8 mm) column, but with the mobile phase of H2S04 0.65 mM at 75°C and a flow of 0.7 ml/min. They use a UV detector at 214 nm and an RI in series. The sample requires only a filtration at 0.45 /im, as described in their survey (24). 

Method. Solutions of amino acids in phosphate buffer (pH 9.3) are mixed with an equal volume of freshly prepared 0.4 M pyridoxal solution (adjusted to pH 9.3) and permitted to stand at 8 °C for 30 min. (The molar ratio of pyridoxal to amino acid should be >75 1.) At this point, 1 ml of sodium tetrahydroborate solution (100 mg/ml in 0.1 N sodium hydroxide) is added and the contents are gently shaken. Excess of sodium tetrahydroborate is destroyed by addition of sufficient hydrochloric acid (pH 1-2) prior to column chromatography. The pyridoxal derivatives are separated on a column (100 X 0.6 cm) of Aminex A-5 ion-exchange resin (Bio-Rad) at a mobile phase flow-rate of 33 ml/h. The eluting solvents consist of 0.2 N buffers at pH 3.40,4.44 and 4.86 and a 0.35 N buffer at pH 5.86 (all of the buffers are sodium citrate). The separation of a number of pyridoxyl-... 

Prior to high-performance liquid chromatography (HPFC), samples were filtered through a 0.2-gm pore size mixed cellulose ester filter (Schleicher Schuell, Dassel, Germany). Buffer components such as acetic acid, citric acid, maleic acid, and succinic acid were separated on an Aminex HPX-87H (Bio-Rad, Hercules, CA) organic acid column at 65°C using a... 

Fig. 17. Elution curve for short-lived W isotopes modeling the seaborgium separation [52J in ARCA II using a solution of 0,1 M HNO3/510 4 M HF with a flow rate of 1 mL/min. The 1.6x8 mm columns are filled with the cation-exchange resin Aminex A6. Reproduced from [52] with the permission of Oldenbourg Verlag.

Stationary Phase Use prepacked macroreticular polystyrene sulfonate divinylbenzene cation-exchange resin (2% to 8% cross-linked, 8- to 25-ptm particle size), preferably in the calcium or silver form. Examples of acceptable resins are Bio-Rad Aminex HPX-87C, or equivalent, for separating DPi-DP4 saccharides, and Aminex HPX-42C and HPX-42A, or equivalent, for separating DP1-DP7 saccharides. Maintain the column at 85° during operation. 

The analyzer uses a heated, high-pressure (up to 4000 psi) anion exchange column, concentration gradient elution with an aqueous acetate buffer for separation and transport of the constituents of the sample mixture, and a recording photometer for detection and quantification of the separated constituents (Fig. 6). Earlier models of this analyzer were housed in standard 24 X 24 X 63 in. cabinets (Fig. 7) however, miniaturized versions with capillary separation columns are now being used (Fig. 8). An anion exchange resin produced by Bio-Rad Laboratories (Aminex A-27) in the size range of 10-15 ju has been found to be satisfactory. 

Totally sulfonated cation exchangers are suitable not only for the separation of weak inorganic and organic acids, but they can also be used for the analysis of monohydric and polyhydric alcohols and aldehydes with a small number of C-atoms. For the separation of monohydric alcohols, Jupille et al. [12] used Aminex HPX-85H (Bio-Rad, Richmond, VA, USA) as the stationary phase and dilute sulfuric acid as the eluent. The corresponding chromatogram is displayed in Fig. 4-14. As on a chemically bonded re-... 

Fig. 4-14. Separation of monohydric aliphatic alcohols on Aminex HPX-85H. - Eluent 0.005 mol/L H2SO4 flow rate 0.4 mL/min detection RI injection volume 20 pL solute concentrations 0.5% (w/w) each of methanol (1), ethanol (2), 2-propanol (3), 2-methylpropanol-l (4), 1-butanol (5), 3-methylbutanol-l (6), and 1-pentanol (7) (taken from [12]).

Delphin and Horwitz investigated sodium isotopic separations in chromatographic experiments using dicyclohexano] 18]crown-6 and [18]crown-6 (see Fig. 11). A steel column was applied which was 50 cm in height and 0.3 cm in diameter and filled with the strongly acidic polystyrene resin Aminex A 7. A mixture of Na and Na which had a nearly equal decay rate for both isotopes was fixed at the top of the column and was then eluted by a solution of methanol/water (80 %/20 %,... 

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