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Química Nova

Print version ISSN 0100-4042On-line version ISSN 1678-7064


MASINI, Jorge Cesar. Demonstrating the fundamentals, potentialities and limitations of sequential injection analysis. Quím. Nova [online]. 2008, vol.31, n.3, pp.704-708. ISSN 0100-4042.

The sensitivity and accuracy of sequential injection methods are dependent on efficient overlapping of reagent and sample zones as they are propelled toward the detector cell. The formation of the reduced phosphomolybdic acid is used to demonstrate that the overlapping efficiency in a fixed reaction coil relies on a suitable choice of reagent to sample volume ratio. Additionally, under poor mixing conditions or highly concentrated samples, the reaction extension is strongly dependent on the reagent concentration. The zone-sampling concept is exploited to determine phosphate in cola-based soft drinks after in-line dilution in an auxiliary coil.

Keywords : sequential injection; spectrophotometry; phosphate.

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