Detection of fumonisin B1: comparison of flow-injection liposome immunoanalysis with high-performance liquid chromatography Ja-an A. Ho * and Richard A. Durst 1 BioAnalytical Chemistry Laboratory, Department of Food Science and Technology, Cornell University, Geneva, NY 14456-0462, USA Received 13 March 2002 Abstract Fumonisins are secondary metabolites of the fungus Fusarium moniliforme, a common mycotoxin in corn, which are known to cause cancer in a number of experimental animals and have been linked to human esophageal cancer in China and South Africa. A high-performance liquid chromatographic (HPLC) method is currently the most widely used method for the quantitative deter- mination of fumonisins. This method utilizes precolumn derivatization with o-phthaldialdehyde, isocratic elution, and fluorescence detection. In this study, the HPLC method was chosen as the reference method to evaluate the reproducibility and accuracy of FILIA (flow-injection liposome immunoanalysis) for the detection of the fumonisin B1 (FmB1). Studies indicate that a recovery of 86–90% could be obtained when commercial yellow cornmeal spiked with FmB1 was extracted in 75% methanol, which correlated favorably (correlation coefficient, r 2 ¼ 0:945) with the result of 80–92% obtained using the flow-injection liposome immunoanalysis (FILIA) system. The data suggest that the FILIA method is comparable to HPLC for the detection of fumonisins in corn, animal feeds, and human foods. Important features of FILIA as compared to HPLC are, most importantly, lower detection limit (ca. 25 lower), and also less complex and faster sample preparation and therefore increased analytical throughput. In addition, 24 human corn-based foods and 6 animal feeds were examined for the presence of FmB1 using HPLC and FILIA. Ó 2003 Elsevier Science (USA). All rights reserved. Keywords: FILIA; Flow injection analysis; Fumonisin B1; HPLC; Immunoassay; Liposome; Mycotoxin Several HPLC 2 methods have been reported for the determination of fumonisins (Fig. 1) in human foods and animal feeds. Since the structures of fumonisins do not contain any useful UV chromophores or fluores- cence characteristics, HPLC with either UV or fluores- cence detection of a derivatized fumonisin is the most commonly used analytical method. Derivatization with maleic anhydride, coupled with reversed-phase liquid chromatography and UV detection [1], enabled the quantitation of fumonisin B1 (FmB1) and FmB2 in culture material of Fusarium moniliforme. However, this method lacked the necessary sensitivity for the deter- mination of fumonisins in naturally contaminated foods and feeds. Other techniques utilizing the derivatization of free amino groups in the fumonisins with reagents such as o-phthaldialdehyde [2], 4-fluoro-7-nitrobenzof- urazan [3], naphthalene dicarboxaldehyde, and fluo- rescamine [4] are suitable for the detection of FmB1 and its homologs, FmB2 and FmB3. However, they cannot detect n-acetylated fumonisin analogs. Wilkes et al. [5] developed a method for determining the purity of FmB1 by HPLC with evaporative light-scattering detection (ELSD). The ELSD is a sensitive tool for underivatized FmB1 and appears to be well suited for the detection of the other low-volatility components present in partially purified F. moniliforme. The analyte of interest in this study is fumonisin B1, which is the most abundant member of the fumonisin familyandaccountsforabout70%ofthetotalfumonisins Analytical Biochemistry 312 (2003) 7–13 www.elsevier.com/locate/yabio ANALYTICAL BIOCHEMISTRY * Corresponding author. Present address: Department of Applied Chemistry, National Chi-Nan University, No. 1 University Road, Puli, Nantou, 545 Taiwan. Fax: +886-49-2917956. E-mailaddresses: jah@ncnu.edu.tw (J.-a.A. Ho), rad2@cornell.edu (R.A. Durst). 1 Fax: 1-315-787-2284. 2 Abbreviations used: HPLC, high-performance liquid chromotog- raphy; FmB1,2,3. fumonisin B1,2,3; ELSD, evaporative light-scatter- ing detection; ELISA, enzyme-linked immunosorbent assay; FILIA, flow-injection liposome immunoanalysis; OPA, o-phthaldialdehyde; TBS, Tris-buffered saline; TCA, tricarballylic acid. 0003-2697/02/$ - see front matter Ó 2003 Elsevier Science (USA). All rights reserved. PII:S0003-2697(02)00393-7