title: Online dynamic pH junction-sweeping for the determination of benzoic and sorbic acids in food products by capillary electrophoresis.
abstract: A simple, low-cost, and efficient online focusing method that combines a dynamic pH junction and sweeping by capillary electrophoresis with polymer solutions was developed and optimized for the simultaneous determination of benzoic acid (BA) and sorbic acid (SA). A sample solution consisting of 2.5 mM phosphate at pH 3.0 and a buffer solution containing 15 mM tetraborate (pH 9.2), 40 mM sodium dodecyl sulfate, and 0.100 % (w/v) poly(ethylene oxide) were utilized to realize dynamic pH junction-sweeping for BA and SA. Under the optimized conditions, the entire analysis process was completed in 7 min, and a 900-fold sensitivity enhancement was achieved with limits of detection (S/N = 3) as low as 8.2 and 6.1 nM for BA and SA, respectively. The linear ranges were between 20 nM and 20 μM for BA and 20 nM and 10 μM for SA, with correlation coefficients greater than 0.992. The recoveries of the proposed method ranged from 90 to 113 %. These satisfactory results indicate that this method has the potential to be an effective analytical tool for the rapid screening of BA and SA in different food products.
authors.affiliation: Department of Applied Science, National Taitung University, 684, Section 1, Chunghua Road, Taitung, 95002, Taiwan.
authors.forename: Shih-Hong
authors.initials: SH
authors.lastname: Hsu
authors.forename: Cho-Chun
authors.initials: CC
authors.lastname: Hu
authors.forename: Tai-Chia
authors.initials: TC
authors.lastname: Chiu
mesh_terms: D019817:Benzoic Acid / Q000032:analysis*; D002253:Carbonated Beverages / Q000032:analysis; D019075:Electrophoresis, Capillary; D005520:Food Preservatives / Q000032:analysis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D013011:Sorbic Acid / Q000032:analysis*; D045730:Soy Foods / Q000032:analysis; D014920:Wine / Q000032:analysis
chemical_list: D005520:Food Preservatives; D019817:Benzoic Acid; D013011:Sorbic Acid