A scheme for obtaining standards and HPLC quantification of leafy vegetable carotenoids

• Published in: Food chemistry 2002, Vol.78 (3), p.389-398
• Main Authors: Kimura, Mieko, Rodriguez-Amaya, Delia B.
• Format: Article
• Language: English
• Subjects: Analysis; beta-carotene; Biological and medical sciences; Carotenoids; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; General aspects; green leafy vegetables; high performance liquid chromatography; HPLC; lutein; Methods of analysis, processing and quality control, regulation, standards; neoxanthin; violaxanthin
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/S0308-8146(02)00203-0

Reliability of data obtained by HPLC directly depends on the accuracy of the calibration. A major difficulty is obtaining and maintaining pure standards. This work presents a strategy for isolating standards by open column chromatography and quantification by HPLC, using leafy vegetables as examples. The purity of standards evaluated by HPLC was 91–97% for neoxanthin, 95–98% for violaxanthin, 97–100% for lactucaxanthin, 92–96% for lutein and 90–97% for β-carotene. Calculation procedures were also evaluated, demonstrating that results obtained with one-point recalibration, straight-line equation (until 30 days after construction of the full calibration curves) and response factors relative to β-carotene were similar (CVs of 1.6–4.0%), being well below between-sample lot natural variation (CVs of 6.1–42.5%). The scheme proposed is relatively low-cost, provides a constant supply of carotenoid standards, including those unavailable commercially, and high sample throughput.