Optimisation and validation of a liquid chromatography–tandem mass spectrometry method for folates in rice

• Published in: Journal of Chromatography A Vol. 1215; no. 1; pp. 125 - 132
• Main Authors: De Brouwer, Veerle, Storozhenko, Sergei, Van De Steene, Jet C., Wille, Sarah M.R., Stove, Christophe P., Van Der Straeten, Dominique, Lambert, Willy E.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 26-12-2008; Amsterdam; New York: Elsevier; Elsevier
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Calibration; Cereal and baking product industries; Chemical constitution; Chromatography, High Pressure Liquid - methods; Economic plant physiology; Folates; folic acid; Folic Acid - analysis; food analysis; Food industries; Freshwater; Fundamental and applied biological sciences. Psychology; LC–MS/MS; liquid chromatography; mass spectrometry; monoglutamate folates; Oryza - chemistry; Oryza sativa; Reproducibility of Results; rice; Rice analysis; Sensitivity and Specificity; tandem mass spectrometry; Tandem Mass Spectrometry - methods; Tri-enzyme treatment; vitamin content; Folates; LC–MS/MS; Rice analysis; Tri-enzyme treatment; Validation; Tandem mass spectrometry; Elution; Gradient; Chemical analysis; Coupled method; Vitamin; Pteridine derivatives; HPLC chromatography; Folic acid; Folate; Optimization; α-Aminoacid; LC-MS/MS; Reversed phase chromatography; Cereal; Quantitative analysis; Rice
• ISSN: 0021-9673
• DOI: 10.1016/j.chroma.2008.11.004

An LC–MS/MS method has been developed and validated for the analysis of six monoglutamate folates in rice. Accurate determination of folates in rice seeds required the optimisation of an extraction procedure encompassing homogenisation, heat treatment, tri-enzyme treatment (α-amylase, protease and deconjugase), centrifugation and ultrafiltration. The resulting extract was loaded onto a Polaris C 18-A column, followed by gradient elution and detection by tandem mass spectrometry. The validated method is sensitive, reproducible, accurate, and linear between 1 and 400
μg/100
g rice (dry weight). The limit of detection and limit of quantification in diluted rice matrix ranged between 0.2 and 1.2
μg/100
g and between 0.6 and 4
μg/100
g, respectively, depending on the compound. Intra- and inter-day precision varied, respectively, from 1.0 to 9.1% RSD, and from 3.4 to 13.5% RSD, except for one compound (19.1% at low concentrations). The accuracy ranged from 96.9 to 115.4%. Matrix effects were compensated for by use of isotopically labelled internal standards. Most folates in rice extracts were stable when kept for 2 weeks at −20 and −80
°C, but degraded after three freeze–thaw cycles or at 4
°C, even when stored protected from light. Our validated method offers a sensitive and versatile approach to determine the level of six different monoglutamate folates in a complex matrix as rice.