The effect of the counterflow in isotachophoresis on the samples containing components of greatly different concentrations has been investigated. The leading electrolyte was 0.01 M histidine hydrochloride and 0.01 M histidine in 0.05% Triton X-100. The terminal electrolyte was 0.01 M
n-caproic acid. The rate of counterflow was adjusted to 200 μl/h and the migration current to 100μA. The capillary tube was (2040) cm long. The samples were four mixtures of sodium nitrate (NaNO
3) and sodium acetate dissolved in 100 ml water; to 50 mg of NaNO
3, (a) 10 times, (b) 30 times, (c) 100 times, and (d) 500 times larger quantity of CH
3COONa were added. With the increase in sample size, the separation was less satisfactory, and the responses were less quantitative. In experiments without a counterflow, the quantitative limits were (a) 5μl, (b) 3μl, (c) 1μl and (d) <1μl in sample sizes. When counterflow was applied for (12.5)h, the mixed zone disappeared and the two components were detected quantitatively. Even sample (d) [NaNO
3: CH
3-COONa=1: 500 by weight] was separated well and the two components were detected quantitatively, with a sample size of about 3μl.
抄録全体を表示