Eluents tetrabutylammonium hydroxide

Determination by oxidation of ascorbic acid (spec A = 548 nm) Diaminetetraacetic acid (DCTA)ZCHjCN used as eluent Tetrabutylammonium hydroxide (TBAH)/aq. CH CN used as eluent KHjPO buffer (pH = 7) lodometric titration... 

Figure 9.145 Separation of adenine nucleotides (mixture of authentic compounds) at pH 9.4 (A) and pH 8.0 (B). Column Knauer RP-18/10, operated with a precolumn. Eluent 9.4% 2-propanol, 3 mAf tetrabutylammonium hydroxide, pH adjusted with t N phosphoric acid. Peaks 1,5 -AMP 2, APS 3, ADP 4, ATP 5,3 5 -PAP 6, PAPS 7, NADP 8, FAD. (From Schwenn and lender, 1980.)...

The addition of even minute amounts of sodium carbonate has a particularly strong effect on the retention behavior of multivalent anions. These comprise, for example, the two iron cyanide complexes Fe(CN)63 and Fe(CN)64, whose separation is obtained with an eluent containing only 3 10 4 mol/L sodium carbonate (see Fig. 5-9), apart from tetrabutylammonium hydroxide and acetonitrile. Lowering the acetonitrile content in favor of sodium carbonate, the resolution between both signals will decrease drastically, although the peak shape of the iron(II) complex will be distinctly improved. 

Fig. 3. Qeft) Separation of the diastraeomeric c-NAD and y-c-NAD by reversed phase HPLC. A C-18 Dynamax scout column (4.6 nun x 25 cm 8 micron packing Rainin Instrument Co., Woburn, MA) was used, with an eluent of 20 mM N 2F 4 pH adjusted to 6.0 using tetrabutylammonium hydroxide, and run at a flow rate of 1 ml/min.

Figure 9.2 Separation of alkylsulfonates by ion-pair chromatography. Eluent 2.0 mM tetrabutylammonium hydroxide in 37% acetonitrile, suppressed conductivity detection (from Ref. [8]).

Depending on the apphcation, a self-regenerated suppressor can also be operated in three diiferent modes, which were described in Section 3.6.4. The most common mode of operation for the CSRS 300 is AutoSuppression in the recycle mode, in which the conductivity cell effluent is used as the source for the required deionized water (see Figure 3.116 in Section 3.6.4). Because in this case an external chemical regenerant such as tetrabutylammonium hydroxide is unnecessary, cost of ownership is significantly reduced, and suppressor operation is simplified. However, this mode of operation can be used only for applications that use pure aqueous eluents. 

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. 

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