Tubular Detector of Silver Solid Amalgam for Electrochemical Measurements in Flow Systems

This paper presents the application of the tubular detector based on silver solid amalgam (TD‐AgSA) for electrochemical determinations of reducible inorganic (Cd 2+ , Zn 2+ ) and organic (4‐nitrophenol) compounds under flow injection analysis conditions. The newly developed TD‐AgSA is simple, robust and inexpensive. The limits of detections of Zn 2+ , Cd 2+ and 4‐nitrophenol are 1.4×10 −6 , 7.0×10 −7 , and 5.0×10 −7  mol dm −3 , respectively (i.e. 0.09, 0.08 and 0.07 ppm). The obtained results proved the long‐term stability of the detector ( RSD of the determination of Zn 2+ , Cd 2+ , and 4‐nitrophenol were 0.8, 0.9 and 0.8 % ( n =10; c Zn =7.7×10 −5  mol dm −3 , c Cd =4.5×10 −5  mol dm −3 and c 4‐NPh =3.6×10 −5  mol dm −3 ), respectively and its applicability for cathodic measurements in aqueous solutions at potentials up to −2 V.