Determination of sodium sulfide based on electrochemiluminescence of rhodamine B at a SWNT modified glassy carbon electrode

Abstract

Electrochemiluminescence (ECL) of rhodamine B (RhB) at a single-wall carbon nanotube (SWNT) modified glassy carbon (GC) electrode has been employed for the determination of sodium sulfide. A linear response (R = 0.99) over a sodium sulfide concentration range of 1.0 × 10⁻¹⁴ to 1.0 × 10⁻¹⁰ mol L⁻¹ and a detection limit of 1.0 × 10⁻¹⁴ mol L⁻¹ can be reached. Furthermore, RhB was covalently linked with SWNT and then modified onto a GC electrode surface to detect sodium sulfide. It was found that the detection limit can be further reduced to 1.0 × 10⁻¹⁶ mol L⁻¹ in the case of a RhB–hexamethylenediamine–SWNT modified GC electrode. This is much lower than other detection methods. The proposed method was applied to the determination of sodium sulfide added into deionized water; the recovery was quite satisfactory with good reproducibility and stability. All these results provide the possibility of developing a novel ECL detection method for sodium sulfide.