Determination of glutathione in individual Ramos cells by capillary electrophoresis with electrochemiluminescence detection

Abstract

This paper reports an approach for the direct determination of glutathione in individual Ramos cells based upon capillary electrophoresis coupled with electrogenerated chemiluminescence using a platinum electrode. The following conditions were suitable for the determination of glutathione: running buffer, 0.05 mol L⁻¹ Na₂HPO₄–NaH₂PO₄ (pH 8.0); concentration of tris(2,2′-bipyridine) ruthenium(II) (Ru(bpy)₃²⁺), 5.00 × 10⁻³ mol L⁻¹; injection voltage, 15 kV; injection time 13 s; separation voltage, 15 kV; detection potential, 1.2 V (vs. Ag/AgCl). Individual Ramos cells were injected into a fused-silica capillary by electromigration and lysed by 0.1% sodium dodecylsulfate. The concentration limit of detection of the method (S/N = 3) was 6.2 × 10⁻⁷ mol L⁻¹. The linear dynamic range was from 1.58 × 10⁻⁶ to 2.00 × 10⁻⁴ mol L⁻¹ with correlation coefficient of 0.9967. The recovery was in the range of 97–103%, and the amount of glutathione in single Ramos cells ranged from 22.0–28.0 fmol. This method indicates a good reproducibility for single cell analysis to provide accurate analytical results.