Anion-exchange columns Dionex

Two anion exchange columns Dionex CarboPac PA1 plus a guard column and CarboPac MAI column with a guard column were used for separation procedure (High Performance Anion Exchange Chromatography). 

Weak anion-exchange column (Dionex AS4A) with elution in a gradient of HNO3 allowed the separation of 8 species within 12 min on-line ICP-MS. 

FIGURE 10.8 Chromatogram of carbohydrates in orange juice. Peak identities a, xylitol b, sorbitol c, glucose d, fructose e, sucrose. Chromatographic conditions CarboPac PAl anion-exchange column (Dionex), 100 mM NaOH mobile phase with a 1 mL/min flow rate PAD at an Au electrode. (Reprinted from Zook, C.M. and LaCourse, W.R., Curr. Sep., 14(2), 48-52, 1995. With permission.)... 

The Dionex system uses a Garbo Pac PA-1 anion exchange column and a CarboPac PA-1 Guard. The column was loaded with 25 pi of the RG solution and eluted with a linear gradient of 0 - 0.5 M NaOAc in 0.1 N NaOH during 50 minutes. The flow rate was 1.0 ml/min and the process was monitored using a PE detector. 

Figure 25-23 Pulsed electrochemical detection of alcohols separated on Dionex AS-1 anion-exchange column with 0.05 M HCIOA. Peaks 1, glycerol 2, elhylene glycol 3, propylene glycol ...

Ding et al. [88] used anion-exchange chromatog-raphy-ICP-MS to determine different forms of chromium in chromium picolinate products which are used as dietary supplements and appear to assist in weight loss. A Dionex AS7 anion-exchange column was used to separate Cr(III)-EDTA chelate and Cr(VI) in the supplements. Only 1% total chromium recoveries were obtained and this was attributed to retention of the chromium species on-column. The use of RP-HPLC proved to be more effective and complete chromium recoveries were obtained, based on the amounts stated on the manufacturer s product labels. 

Goossens and Dams [89] developed a method to separate chlorine and sulphur interferents from V, Cr, Cu, Zn, As and Se in various samples using a Dionex-1 anion-exchange column and dilute nitric acid eluent. The analytes were collected in the eluent whereas Cl-, CIO, S04- and SO3- interferents... 

Shown in Fig. 2.8 is a schematic diagram of the Dionex ion exchange liquid chromatograph used by Smee et al. [40], The instrumentation consists essentially of a low capacity anion exchange column, the separator , a high capacity cation exchange column, the suppressor and the detection system, a high sensitivity conductivity meter and recorder. 

A gas chromatograph (Yanaco G-3810) was equipped with a thermal conductivity detector (TCD) and a flame ionization detector (FID). Molecular Sieve 5A and Porapak Q were used for CO and Hj analysis in the TCD and CH4 and C2H4 analysis in the FID, respectively. Soluble products such as CH3OH, CH3CHO, and CjHjOH were analyzed by the FID after electrolysis for 5 h. Formate ions and other anions in the solution were analyzed by means of an ion chromatograph (Dionex DX-lOO) equipped with an anion exchange column (lonPac ICE-ASl), an anion exchange micromembrane suppressor, and a conductivity detector module. 

The A A detection of arsenic was at 193.7 nm. The HPLC column was a Dionex anion exchange column with 0.2 M (NHJ. CO. in aqueous methanol as the eluting solvent. The bracketed areas were isolated by preparative... 

The HPLC-GFAA instrumentation and analyses condition have been described previously (see references 25-28). The AA detection of arsenic was at 193.7 nm. The HPLC column was a Dionex anion exchange column with 0.2M (NH ) CO in aqueous methanol as the eluting solvent. The GC-MS analyses were accomplished using a Finnigan 4023 mass spectrometer system with a 30 m x 0.3 mm DB-5 (J W) capillary column, conditions 55° 3 min.) - 300°/min. 

Table 62. Dionex anion-exchange columns (H = high. M = medium. L = low).

To elute the oligonucleotide, a gradient from 100 to 150 mM NaC104 at a rate of 15 mL/min for a Dionex NucleoPac anion-exchange column was used. 

A matrix elimination IC with postcolumn reaction detection was developed for the determination of iodide in seawater (Brandao et al, 1995). A Dionex lonPac ASH anion-exchange column was used, and the mobile phase contained sodium chloride to remove interference of the... 

The simultaneous separation of the eight common arsenic compounds (arsenous acid, arsenic acid, MA, DMA, AB, TMAO, AC, TETRA) within one chromatographic run was achieved with a Dionex Ion Pac AS 7 high-capacity anion-exchange column with a nitric acid gradient and the addition of 1,2-benzenedisulfonic acid as ion-pairing reagent (59). This separation was only... 

Figure 1 Expanded chromatograms from Dionex ion chromatograph of enzyme hydrolysates of corn and potato starch, the use of a single enzyme, amyloglucosidase (AMG), and a mixture of AMG, a-amylase (a-A), and pullulanase (PU), to show the effect on hydrolysis of limit dextrin. Anion exchange column AS6, with pulsed amperometric detection. Gradient flow solvents (1) ISOmmolT NaOH and (2) ISOmmoll NaOH + 500mmol I NaOOCCHs. Postcolumn addition of 0.3mmoll NaOH.

Two compoimds that are currently generating much concern are azide and perchlorate, salts of which are cm-rently used in the explosives and pyrotechnics industry, with perchlorate also used as a primary oxidant in solid rocket fuel. IC can be used for the monitoring of both analytes in natural and treated waters. For perchlorate, EPA Method 314.0 (Determination of perchlorate in drinking water by ion chromatography) has been developed, which suggests the use of a Dionex lonPac AS16 anion exchange column (or equivalent) with a 35 mM NaOH eluent and suppressed conductivity detection. 

A further development is the Dionex HPLC AS5A-SU analytical anion exchange column. 

Table 6.2 Dionex Ion Pac hydroxide-selective, anion-exchange columns.

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