Multicommutation in flow analysis. Part 4. Computer-assisted splitting for spectrophotometric determination of copper and zinc in plants

• Published in: Analytica chimica acta Vol. 332; no. 2; pp. 173 - 178
• Main Authors: Oliveira, C.C., Sartini, R.P., Reis, B.F., Zagatto, E.A.G.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 21.10.1996; Elsevier
• Subjects: Analytical, structural and metabolic biochemistry; Biological and medical sciences; Differential kinetic analysis; Flow analysis; Fundamental and applied biological sciences. Psychology; Inorganic compounds; Multicommutation; Other biological molecules; Splitting; Multicommutation; Splitting; Differential kinetic analysis; Flow analysis; Metal complex; Kinetic method; Transition metal Complexes; Computer control; Inorganic element; Switching; Zinc; Plant; Flow regime; Detection limit; Simultaneous measurement; Copper; Spectrophotometry; River water; Quantitative analysis; Ultraviolet visible spectrometry
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/0003-2670(96)00237-1

An improved splitting process in flow analysis accomplished by means of a computer controlled three-way solenoid valve is proposed. This valve is located at the splitting site, and defines the flow pattern and the portions of the processed sample delivered to each emergent stream. As an application, the simultaneous spectrophotometric determination of copper and zinc in plant digests was selected. The method is based on metal complexation with cyanide, differential kinetics of decomplexation, and reaction with Zincon. The proposed system is very stable and handles 45 samples per hour which corresponds to 0.27 mg Zincon per determination. Precise measurements (r.s.d. = 0.7% and 1.7% for first and second peaks) are obtained within 0.00–1.00 mg 1 −1 Cu and 0.00–2.00 mg 1 −1 Zn. Detection limits are 0.05 and 0.04 mg l −1 for Cu and Zn. Results are in agreement with standard reference materials.