Eluents tetramethylammonium hydroxide

For anion analysis, the regenerant must supply a source of hydrogen ions to convert the eluent anions to a less conductive form. The most common regenerant is dilute sulfuric acid, whereas for cation analysis, the most common regenerant is hydroxide (sodium, potassium, or tetramethylammonium hydroxide). 

Fig. 5-29. Separation of tetramethylammonium hydroxide. - Separator column IonPac NS1 (10pm) eluent 0.001 mol/L hexanesulfonic acid / acetonitrile (94 6 v/v) flow rate 1 mL/min detection suppressed conductivity injection volume 50 pL solute concentration 20 ppm.

AutoNeutralization also has to be applied for trace analysis of anions in bases such as sodium hydroxide, ammonium hydroxide, tetramethylammonium hydroxide, and tetrabutylammonium hydroxide, because the high concentration of hydroxide in the matrix would in practice act as an eluent and thus render impossible the preconcentration of anions in a concentrator column [247]. In the semiconductor industry, quaternary ammonium bases serve as developers for light-sensitive paints and, therefore, also have to be investigated for anions responsible for corrosion. As shown in Figure 10.145, detection limits in the midmicrogram/Liter range are obtained without difficulty when applying AutoNeutralization. 

Figure 10.145 Separation of anions in 25% tetramethylammonium hydroxide after Auto-Neutralization. Separator column lonPac AS12A eluent 2.7 mmol/L Na2C03 + 03 mmol/L NaHCOi flow rate 13 mL/min detection suppressed conductivity injection volume ...

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