Eluents borate/gluconate

Figure 12.5 Separation of a seven-anion standard with single-column ion chromatography. Column [Chromatographic conditions IC-Pak Anion HR, 4.6 mmx7S mm. Waters Corp. Eluent borate/gluconate. Sample seven-anion standard (1) fluoride (2) bicarbonate (3) chloride (4) nitrite (S) bromide (6) nitrate (7) phosplmt (8) suUite. Detection conductivity. (Qiromatogram courtesy of Waters Corp.)...

Fig. 3-61. Separation of inorganic anions using a borate/gluconate buffer as the eluent. - Separator column TSK Gel IC-PW eluent 0.0013 mol/L Na2B407 + 0.0058 mol/L H3B03 + 0.0014 mol/L potassium gluconate/acetonitrile (88 12 v/ v), pH 8.5 flow rate 1.2 mL/min detection direct conductivity injection 100 pL anion standard (5 to 40 ppm) (taken from [66]).

Fig. 72. Anion separation using borate gluconate eluent anion capability...

Another suitable eluent for anion chromatography is a solution containing boric acid and a polyol, gluconic acid. These substances combine to give acids that are stronger than boric acid. At pH 8.5, the usual pH for borate-gluconate eluents, most of the acids are ionized and the eluting power is adequate. The conductivity of this eluent is low, and rises when other anions are eluted. 

Figure 3.139 Separation of inorganic anions using a borate/gluconate buffer as eiuent. Separator column TSK Gel IC-PW eluent ...

The nature of ester formation between borate and D-mannitol, D-glucitol, D-fructose and D- lucose in aqueous solution at pg 6 - 12 has been elucidated using B- and C-n.m.r. spectroscopy. In order to better understand the action of a gluconate-borate eluent for elution of anions from an anion-exchange resin, the structural features of such solutions have been investigated by potentiometric titrations and C-n.m.r. spectroscopy. Reference to borate esters as transport media in a model membrane will be found in Chapter 2. 

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