Eluents isoconductive

Consider two eluents with different elution power containing the same eluent ions but different cations with their respective equivalent conductivities A + and A2+. Under isoconductive conditions, the background conductivity Gx of the weaker eluent equals that of the stronger eluent G2. Taking Gx = G2 Eq. (97) may be rearranged so that the concentrations cx and c2 of both eluents are related to the corresponding equivalent conductivities ... 

Fig. 3-126. Comparison of the conductivity change resulting from a pure concentration gradient (A) with that obtained under isoconductive conditions (B). - Separator column Waters IC-Pak Anion eluent see Fig. 3-23 (taken from [135]).

In comparing the concentration gradient concept with subsequent chemical suppression, the chromatogram of various inorganic anions in Fig. 3-127 that was obtained with isoconductive eluents clearly shows the limitation of this technique. Although the analysis time for the separation shown is shorter than under isocratic conditions, an improvement in the resolution between the signals, especially in the first part of the... 

Fig. 3-127. Separation of various inorganic anions with an isoconductive eluent. - Separator column Waters IC-PAK Anion eluent see Table 3-23 (eluent switching at the time of injection) detection direct conductivity injection volume 100 pL solute concentrations 1 ppm fluoride (1), 2 ppm carbonate (2) and chloride (3), 4 ppm nitrite (4), bromide (5), and nitrate (6), 6 ppm orthophosphate (7), 4 ppm sulfate (8) and oxalate (9), 10 ppm chromate (10), and molybdate (11) (taken from [135]).

Table 3.28 Eluent composition for a concentration gradient (A) and an isoconductive eluent (B) according to Figure 3.206.

Figure 3.207 Separation of various inorganic anions with an isoconductive eluent. Separator column Waters IC-PAK Anion eluent see Table 3.28 (eluent switching at the time of injection) detection nonsuppressed conductivity injection volume lOOpL peaks 1 mg/L fluoride (1), 2 mg/L each of carbonate (2) and...

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