Anionic column

In this experiment phosphate is determined by singlecolumn, or nonsuppressed, ion chromatography using an anionic column and a conductivity detector. The mobile phase is a mixture of n-butanol, acetonitrile, and water (containing sodium gluconate, boric acid, and sodium tetraborate). 

Precipitation diagram. Choose the cation row and read across to the anion column. If the block is blank, no precipitate will form. If the block is colored, a precipitate will form from dilute solution. Where a formula is given, that is the only cation-anion combination in that block that will precipitate. 

Anions Column packed with anionic luminol derivative bound to a strong anion-exchange resin, displaced derivative-H202-[Fe(CN)6]3- CL 1.0 pM SO42--5.0 pM Br" 34... 

Flow Rate Detector Sensitivity Anion Columns ... 

Dissolution Cation Column Evaporation Anion Column Evaporation... 

Chemistry. The indium metal was melted (mp 156°C) into a flask where it was dissolved in hot 6 M HC1. Since the target material was known to contain Sb impurity, filtration was required at this point in the procedure. After filtration the solution was adjusted to 3 M HC1 by the addition of a suitable volume of distilled water. Table I is a list of the elements that must be separated to obtain pure Cd-109. This solution was applied to an AG-1X8 anion column, 200 to 400 mesh (8). The column was 1.2 cm in diameter with a total bed volume dependent on the quantity of target used. Bed volumes of 20 ml and 40 ml were successfully used. 

Fibre or micromembrane suppressors of high ionic capacity have now taken over from chemical suppressors. With dead volumes in the order of 50 pi, they allow gradient elution with negligible drift in the baseline. Figure 4.8a shows the passage of an anion A- in solution in a typical electrolyte used for anionic columns through a membrane suppressor. 

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. 

Determination of cyclamate using Dionex AS4A anion column and a mobile phase of 140 mg Na2C03/L was described by Biemer (17). Wu et al. (47) also used Dionex AS4A-SC for the determination of cyclamate elution, however, was performed with a 5 mM Na2B407 solution. 

The neptunium was purified by an anion column, and alpha pulse analysis revealed no other species than The uranium solutions... 

It is usual to degas demineralized water produced by weak base anion schemes, but the presence of dissolved carbon dioxide helps suppress the pH across the anion loading cycle thereby assisting ionization of the free base form functional groups. Therefore it is preferred to position the degasser downstream, not upstream, of the weak base anion column especially if the raw water has a low EMA value. 

The first regeneration of the strong base anion exchange resin with a near stoichiometric quantity of sodium hydroxide converts the loaded dichromate form of the resin to the chromate form whereafter it is able to efficiently take up chromic acid again. The anion column effiuent of sodium chromate may be cation exchanged across a strong acid resin in the hydrogen form to recover chromic acid ... 

Chloride ion concentration was measured by ion chromatography with a Dionex Bio LC chromatograph equipped with a Dionex pulsed electrochemical detector and a Dionex PAX-100 metal-free anion column (25 cm long, 4.6 mm i.d.). The eluent was a mixture of 80% H20, 10% acetonitrile, and 10% 191-mM NaOH the flow rate was 1 mL/min, and the injection loop volume was 50 p,L. 

Trace amounts of gold can be separated (as chloride complex) from many other metals (including macro-amounts of copper), on strongly basic anion exchangers [33,34], A sample solution in dilute HCl is passed through an anionic column. Trace amounts of gold from anode slime have been pre-concentrated on Amberlite XAD-7 [35]. 

Figure 6J.0. Separation of oxaiate, thiosulfate and other anions. Conditions Allsep anion column 100 X 4.6 mm, 4 mMphthalicacid.pH 4.2,1.0 mL/minat35 conductivity detector (Courtesy Alltech).

To understand the mechanism of a separation, take for example an anionic column containing quaternary ammonium groups, in equilibrium with a mobile phase composed of a solution of hydrogenated carbonate anions (e.g. sodium counter ions). All of the cationic sites of the stationary phase find themselves paired with anions of the mobile phase (Figure 4.2). 

Alternately, if the problem consists in the separation of a mixture of anions on an anionic column (cationic material), with an eluent containing dilute sodium hydroxide, a membrane allowing the diffusion of cations will be chosen. At the cathode, the passage of hydronium ions towards the main flow of electrolyte will neutralize OH ions. At the anode, Na ions will migrate out of the mobile phase and will react with OH ions. 

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