Formation of two reaction zones in flow-injection systems for kinetic determinations of cobalt and nickel

✍ Scribed by Alfonso Fernandez; M.Dolores Luque de Castro; Miguel Valcárcel

• Book ID: 104100416
• Publisher: Elsevier Science
• Year: 1987
• Tongue: English
• Weight: 757 KB
• Volume: 193
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/s0003-2670(00)86143-7

✦ Synopsis

The injection of a large sample volume (ca. 1 ml) into a single-channel flow-injection system was studied with a dye (to examine physical dispersion) and with chemical systems having easily-controlled reaction rates (to examine chemical kinetics). With the dye, the response curve has a central plateau caused by non-mixing of carrier and sample. When a chemical reaction takes place, two peaks are obtained with a central minimum corresponding to little or no mixing and reaction. Comparison of these two types of response provides relationships of analytical interest between response parameters and variables in the flow-injection system. The configuration is used for individual kinetic determinations of cobalt and nickel (2.5-30 pg ml-') based on the rate of their complex formation with 2-hydroxybenzaldehyde thiosemicarbazone. Sample injection rates were 15 h-' for cobalt and 40 h-' for nickel. Differential kinetic determinations of cobalt and nickel in mixtures are based on the increment in peak height (or area) between the two peaks obtained for each injection; sample throughput is 7 h-l.