Sequential Injection Titration with Spectrophotometric Detection for the Assay of Acidity in Fruit Juices
Open Access
- 12 January 2006
- journal article
- Published by Springer Science and Business Media LLC in Analytical Sciences
- Vol. 22 (1), 157-160
- https://doi.org/10.2116/analsci.22.157
Abstract
A simple sequential injection analysis (SIA) with spectrophotometric detection for an assay of acidity in fruit juice was investigated. An alkaline reagent (sodium hydroxide), a sample and an indicator (phenolphthalein) were first aspirated and stacked as adjacent zones in a holding coil. With flow reversal through a reaction coil to the detector, zone penetration occurred, leading to a neutralization reaction that caused a decrease in the color intensity of the indicator being monitored for absorbance at 552 nm. The effects of various parameters were studied. Linear calibration graphs for acidities of 0.2 - 1.0 and 0.5 - 2.5% w/v citric acid as a standard, with a relative standard deviation of 1% (acidity of 0.3 - 0.6% w/v as citric acid, n = 11) and a sample throughput of 30 samples h-1, were achieved. The developed method was validated by a standard titrimetric method for assaying the acidity of fruit juice samples.Keywords
This publication has 12 references indexed in Scilit:
- Separation and determination of di- and tricarboxylic acids in fruits by capillary zone electrophoresis with amperometric detectionAnalytica Chimica Acta, 2000
- Development and validation of a capillary electrophoresis method for direct measurement of isocitric, citric, tartaric and malic acids as adulteration markers in orange juiceJournal of Chromatography A, 2000
- Flow injection conductimetric or spectrophotometric analysis for acidity in fruit juiceAnalytica Chimica Acta, 1998
- Gas chromatographic determination of organic acids from fruit juices by combined resin mediated methylation and extraction in supercritical carbon dioxideJournal of Chromatography A, 1997
- Separation and determination of four artificial sweeteners and citric acid by high-performance anion-exchange chromatographyJournal of Chromatography A, 1997
- Simultaneous quantitation of citrate and isocitrate in citrus juice by a flow-injection method based on the use of enzyme reactorsAnalytica Chimica Acta, 1996
- Use of ion chromatography for the measurement of organic acids in fruit juicesJournal of Chromatography A, 1995
- Determination of titratable acidity and ascorbic acid in fruit juices in continuous-flow systemsAnalytical and Bioanalytical Chemistry, 1993
- Sequential injection: a new concept for chemical sensors, process analysis and laboratory assaysAnalytica Chimica Acta, 1990
- Routine spectrophotometric determination of citric acid in milk powdersThe Analyst, 1987