The working principle of electrostatic eliminator

In chemical inhibition conductivity detection, the inhibition reaction is an important factor for the high sensitivity and selectivity of ion chromatography.
There are several detection methods for ion chromatography, among which conductivity detection is the most important, because it has generality to ions in aqueous solution. However, because of its universality, as the detector of ion chromatography, it poses a problem, which has very high detection signal of eluent, which makes it difficult to identify the signal samples produced by ion leaching. Simple and ingenious solutions proposed by Small et al is used as alkali metal salts of weak acid leaching liquid separation of anions, inorganic acid (acid or hydrochloric acid) as eluent cation separation. When the separation of anionic eluent of a hydrogen separation between the column and the detector by a (H+) resin packed column type strong acidic cation exchange resin; cation exchange column analysis, through the OH- anion is. In this way, the weak acid salt anion in eluent is protonated to produce weak acid cation; eluent acid is neutralized to form water, thus greatly reduce the leacheate conductance itself. This column is called an inhibitory column.

Suppressor mainly has two functions, one is to reduce the background conductivity of the eluent, two is to increase the conductance of the detected ions and improve the signal-to-noise ratio. Figure 8-4-2 illustrates the role of chemical suppressors for ion chromatography. The sample is mixed solution of F-, Cl-, SO42- anion, the eluent is NaOH. If the samples were eluted after the column is obtained directly into the conductivity cell, chromatogram of the upper right. The very high background conductance in the figure comes from the eluent NAOH, the peak of the measured ions is very small, that is, the signal-to-noise ratio is not good, a large system peak (corresponding to the anion in the sample) in front of the F- peak. When the eluent by chemical suppressors enters the conductivity cell, was lower in figure 8-4-2 right of the chromatogram. In suppresser, OH- and H+ in eluent combine to form water. The sample ions into the conductivity cell in aqueous solution with low conductance background, rather than the high background of NaOH solution; the measured ion counter ions (cations) and eluent, Na+ together into the wastewater, thus eliminating the system peak. Change in solution and the sample anion cation corresponding to H+, the conductivity detector is the sum of the anionic and cationic conductance detection solution, and the cation H+, the highest molar conductance, therefore the sample A- and H+ anion molar conductance sum has also been improved.
Suppressor has gone through four stages of development. The first column filled resin suppressor is inhibited, the main drawback is that can not work continuously after H+ or OH- resin consumption need to stop regeneration. Another disadvantage is the larger dead volume. The tubular fiber membrane suppressor 1981 commercialization without stopping regeneration, continuous work, the disadvantage is moderate inhibitory capacity and poor mechanical strength of it. The third stage is the 1985 tablet developed micro membrane suppressors, not only can work continuously, and can restrain the high capacity, meet the requirements of gradient elution. In 1992 to enter the market‘s own regeneration suppressor is the fourth stage, the suppressor reagentfree to provide H+ or OH-, but produced by electrolysis of water to H+ or OH- to meet the needs of chemical Suppressors

Ion, its latest model is SRS - ULTRA. The suppressor balance fast, low background noise, durable, working temperature from room temperature to 40 DEG C, and can be as high as 40% in organic solvent (organic solvent used in reversed-phase liquid chromatography) the presence of normal work. Although the resin filling is the first generation of suppressor suppressor. Because of its simple production (can make their own), cheap, inhibit the capacity of medium, is still in use. So the following will be discussed in detail the automatic regeneration of resin filled suppressor and the most advanced continuous type suppressor.