High-performance liquid chromatographic separation and quantification of citric, lactic, malic, oxalic and tartaric acids using a post-column photochemical reaction and chemiluminescence detection.
An HPLC method was developed for the determination of citric, lactic, malic, oxalic and tartaric acids by chemiluminescent detection following online irradiation with visible light. The organic acids were irradiated with visible light in the presence of Fe3+ and UO2(2+) to generate Fe2+, which was determined by measuring the chemiluminescence intensity in a luminol system in the absence of added oxidant. Factors affecting the photochemical and chemiluminescence reactions were optimised so that their contribution to the total band-broadening was negligible. The chromatographic separation was performed on a C18 column under isocratic reversed-phase conditions using 0.005 M H2SO4 mobile phase. The optimised method was validated with respect to linearity, precision, limits of detection and quantification, accuracy specificity and robustness. The applicability of the assay was demonstrated by analysing these compounds in real samples such as milk, fruit juices, soft drinks, wine and beer.
Pérez-Ruiz
Tomás
T
Department of Analytical Chemistry, Faculty of Chemistry University of Murcia, 30071 Murcia, Spain. tpr@um.es
Martínez-Lozano
Carmen
C
Tomás
Virginia
V
Martín
Jesús
J
D000143:Acids / Q000032:analysis* / Q000302:isolation & purification; D000818:Animals; D001515:Beer / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D019343:Citric Acid / Q000032:analysis; D005504:Food Analysis / Q000379:methods*; D005638:Fruit / Q000737:chemistry; D019344:Lactic Acid / Q000032:analysis; D008163:Luminescent Measurements; D008293:Malates / Q000032:analysis; D008892:Milk / Q000737:chemistry; D019815:Oxalic Acid / Q000032:analysis; D010777:Photochemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013644:Tartrates / Q000032:analysis; D014920:Wine / Q000032:analysis
D000143:Acids; D008293:Malates; D013644:Tartrates; D019343:Citric Acid; D019344:Lactic Acid; C030298:malic acid; D019815:Oxalic Acid; C029768:tartaric acid