Aminex column

Analysis of sugars in must is usually performed by using an Aminex column and refractometer as detector. The HPLC chromatogram from a grape must analysis performed in this way is shown in Figure 1.8. 

By performing HPLC analysis using the Aminex column, the chromatograms shown in Figure 1.11 (standard solution) and 1.12 (wine... 

By using both C18 and Aminex HPLC column, succinic, citramalic and fumaric acid can also be determined in the same run of the other organic acids. With C18 columns, these compounds exit in the chromatogram after citric acid in the sequence succinic-citramalic-fumaric in the chromatogram using the Aminex column, succinic acid exits close to shikimic acid, the fumaric acid peak falls between those of lactic acid and acetic acid. 

Table 1.2 Data percentage of parameters determined by HPLC analysis (Aminex column) with respect to the traditional methods. (From Schneider et al., 1987 Testa, 1991).

Xylose, xylitol, and ethanol were analyzed using LC-IOAD high-performance liquid chromatography (Shimadzu, Japan), equipped with an HPX-87H Aminex column (Bio-Rad) and a RID-IOA refractive index detector. The column was maintained at 55 °C and eluted with 5 mmol/L H2SO4 at a flow rate of 0.4 mL/min. 

The relative retention of Co(II) and Ni(II) was the same for each of the three columns. There were, however, indications that the mechanism of ion-exchange was different for each column. For instance, the relative positions of the Co(II) and Ni(II) curves for the Brownlee and Aminex columns using a citrate eluent (curves 1 and 3, Fig. 6.4) are reversed. Although the data for the Nucleosil column were not shown, the authors indicate that the HETP values were constant over the range of citrate concentrations studied. 

Figure 3. Typical chromatogram of UV-ahsorhing constituents of a 0.15-ml sample of urine. Conditions 150-cm anion exchange column (1215 fi, Aminex A ZI) bujfer, acetate at pH 4.4 gradient, buffer concentration from 0.015M to 6M flow rate, 10.5 ml/hr, coUimn temperature, 25°C for first 5 hr and 60°C thereafter (34).

A complete post-column LC system for the analysis of oxime carbamates using this approach is commercially available (Pickering Laboratories). Alternative post-column hydrolysis conditions 50 X 4.0-mm i.d., 15 p.m, Aminex A-27 column (Bio-Rad), 120°C. 

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. 

Cyclodextrin Action Pattern. The action pattern of alpha-, beta-, or gamma-cyclodextrin was determined by BioRad Aminex Carbohydrate HPX-42A HPLC with two columns in tandem at 85 C eluting with glass distilled water as at a flow rate of 0.6 ml/minute. Detection was by refractive index. 

All reactions were run in a Parr stirred autoclave (Model 4561) at 1000 psi H2 and 200°C for 6h. A weighed quantity (0.5 g dry basis) of the catalyst, Ru/C or Ni/Re/C, was introduced into the reactor and reduced at 250 C and 200 psi H2 (Ru/C) or at 280°C and 500 psi H2 (Ni/Re/C) for 13 hours. After cooling, 100ml of solution (l.OM GO and O.l-l.OM KOH) was added to the closed reactor. For reactions in solvent mixtures, entries 1-4 in Table 2, the water/solvent ratio was 1/9 (v/v). When the solvent was either t-BuOH or 1,4-dioxane, 1.5 g of water was added to the solution to facilitate dissolution of KOH, because of its low solubility these solvents. Once steady state was achieved following heatup, samples were taken at 30 minute intervals for the first hour, and then hourly, and analyzed via HPLC. The HPLC column was a BIORAD Aminex HPX-87H run at 65 C with 5mM H2SO4 as the mobile phase at a flow rate of 0.6mFmin, using both UV (210 nm) and refractive index (RI) detection. 

Liquid chromatography (Waters, Alliance 2695 pump) is performed using an Aminex HPX-87C column (250x4.0 mm, bead size 9 pm, Bio-Rad Laboratories, Veenendaal, The Netherlands). An isocratic eluent of 40% acetonitrile/water is used, with the column kept at 65°C. The flow rate is set to 0.4 ml/min and is split after the analytical column in a ratio of 1 2, resulting in an inlet flow into the tandem mass spectrometer of 200 pl/min 20 pi of sample is injected onto the column and the total run time is 24 min. 

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... 

Figure 10. Reaction chromatograms for A, Amstel river water and B, Amstel river water fortified with 3 ng of aldicarb (peak 1) 3 ng of methomyl (peak 2) 5 ng of propoxur (peak 3) 5 ng of carbaryl (peak 4) and 10 ng of methiocarb (peak 5). Conditions 150-mm X 4.6-mm i.d. column packed with Spherisorb ODS mobile phase of 50% water and 50% methanol (v/v) at a flow rate of 1.0 mL/min 60-mm X 4.6-mm i.d. reactor column packed with Aminex A-28 reaction temperature of 100 °C OF A reagent flow rate of 30 pL/min detection with Perkin-Elmer Model 204A fluorescence spectrometer excitation wavelength of 340 nm emission wavelength of 455 nm. (Reproduced with permission from reference 46. Copyright 1983 Elsevier Scientific Publishers.)...

High-performance liquid chromatography (HPLC) system with refractive index detector and HPLC column (e.g., Aminex HPX-87H, Bio-Rad) fitted with suitable guard column... 

As stated in Basic Protocol 1, the method of HPLC used may change depending on the organic acids present in the sample. This method uses a Bio-Rad Aminex HPX-87H column for HPLC analysis. An internal standard is important for the analysis of organic acids. This provides a means of not only determining if the analysis is working but also quantitating the percent recovery of the method. 

High-performance liquid chromatograph (HPLC e.g., Waters Chromatography) equipped with column heater, solvent pump, UV detector (set at 214 nm), integrator, autosampler, and (for manual injection) 10-p.l sample loop Aminex HPX-87H column (Bio-Rad)... 

Equilibrate an Aminex HPX-87H column and guard column with mobile phase (0.005 M H2S04) for >30 min prior to the first injection. 

Bio-Rad Life Sciences Group. Bulletin 1928. US/EG REVA. Guide to Aminex HPLC Columns for Food and Beverage, Biotechnology, and Bio-Organic Analysis. Bio-Rad Life Sciences, Hercules, Calif. 

Provides a good description of the Aminex HPX-87H column (see Basic Protocol 2) and its applications. 

Typical applications of ion exchange in sugar analysis include (a) complexation of borates, which accentuates ionic interactions with the exchanger (27), (b) use of hydroorganic eluents, especially acetonitrile/water, with rigid, fine-particulate anion columns (28), (c) use of basic eluents, since most carbohydrates are weak acids with pKfl of 12-13 (29), (d) complexation with cations, Pb2+, Ca2+ and Ag+ being the most frequently employed, (e) the use of cation exchangers in a heavy metal form, e.g., Aminex HPX-85. 

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