Indirect Atomic Absorption Spectrometric Determination of Ammonia, Thiosulfate and Cyanide in an Unsegmented Flow System

Abstract

A flow injection analysis method (FIA), has been developed for the determination of cyanide, thiosulfate and ammonia by atomic absorption spectrometry (AAS). Aqueous solution of the analyte was injected into an on-line column containing glass beads and packed with silver chloride and deionized water was used as the carrier. The analyte dissolves the silver chloride and the dissolved silver complex is introduced to the nebulizer of the AAS. This method has proved to be sensitive, simple and precise. Detection limits of 1.0 × 10⁻⁷ M, 5.0×10⁻⁷ M and 5.0x10⁻⁶M were obtained for thiosulfate, cyanide and ammonia, respectively. The precision of the technique was 2.0%, 2.4% and 1.4% in case of thiosulfate, cyanide and ammonia, respectively. The effects of flow rate and sample volume on the FIA/AAS signals are presented.

Key Words:

• Ammonia
• Thiosulfate
• Cyanide Flow Injection Analysis
• Atomic Absorption Spectroscopy
• Indirect Analysis