Determination of citric acid in soft drinks using flow injection with potentiometric detection

• Type: Article in International Scientific Journal
• Date: 1999

Authors

Lima, JLFC (Author) FFUP; Delerue Matos, C (Author) Other; Carmo, M (Author) Other; Vaz, VF (Author) Other; Silva, J (Author) Other

Journal

Title: Fresenius' Journal of Analytical Chemistry

Vol. 364

Pages: 266-269

ISSN: 0937-0633

Publisher: Springer

Indexing

ISI Web of Knowledge - 12 Citations

Scopus - 12 Citations

Other information

Authenticus ID: P-001-464

DOI: 10.1007/s002160051335

Abstract (EN): A flow injection analysis (FIA) system with potentiometric detection has been developed for the determination of citric acid in commercial fruit juices using a copper-selective tubular electrode. It consists of the complexation of citrate ion with copper(II) ion, monitoring the free copper (II) concentration. Linear relationships between the potential and log concentrations of citric acid in the range of 1 x 10(-3) mol/L - 1 x 10(-2) mol/L were attained with samples injected in the system without prior treatment. Repeatability was determined by assessing the relative standard deviation for ten replicate injections of different juice samples which varied from 1.2% to 3.0%. The results provided by the automated system were compared with those of an enzymatic conventional method used for the analysis of citric acid in food and a relative deviation of less than 4.0% was found. Recovery trials resulted in values from 97.0% to 101.0%. The system allows a sampling frequency of 60 samples/h.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 4