Determination of fumonisins B1 and B2 in Portuguese maize and maize-based samples by HPLC with fluorescence detection

Abstract

Fumonisins B 1 (FB 1 ) and fumonisin B 2 (FB 2 ) are the main members of a family of mycotoxins produced by Fusarium verticillioides, Fusarium proliferatum, and other fungi species of the section Liseola. The present work shows the results of comparative studies using two different procedures for the analysis of fumonisins in maize and maize-based samples. The studied analytical methods involve extraction with methanol/water, dilution with PBS, and clean-up through immunoaffinity columns. Two reagents (o-phthaldialdehyde and naphthalene-2,3-dicarboxaldehyde) were studied for formation of fluorescent derivatives. The separation and identification were carried out by high-performance liquid chromatography with fluorescence detection. The optimized method for analysis of fumonisins in maize involved extraction with methanol/ water (80:20), clean-up with an immunoaffinity column, and derivatization with naphthalene-2,3-dicarboxaldehyde (NDA). The limit of detection was 20 μg kg −1 for FB 1 and 15 μg kg −1 for FB 2 . Recoveries of FB 1 and FB 2 ranged from 79% to 99.6% for maize fortified at 150 μg kg −1 and 200 μg kg −1 , respectively, with within-day RSDs of 3.0 and 2.7%. The proposed method was applied to 31 samples, and the presence of fumonisins was found in 14 samples at concentrations ranging from 113 to 2,026 μg kg −1 . The estimated daily intake of fumonisins was 0.14 μg kg −1 body weight per day.

Occurrence of fumonisins B1 and B2 in broa, typical Portuguese maize bread

“…In this study, it was observed that maize flour, the main ingredient of broa, presented the highest mean concentration of FB 1 , 822 μg kg − 1 , while FB 2 presented a mean value of 173 μg kg − 1 , and one sample presented a total FB 1 + FB 2 contamination of 2026 μg kg − 1 (Lino et al, 2006). The comparison with other European countries is somehow difficult regarding the few reports of contamination by fumonisins in this kind of goods.…”

“…Extraction, clean-up, and LC-FD determination were performed according to Lino et al (2006). Briefly, ground samples were extracted with methanol:water (80:20, v:v), and centrifuged for 15 min at 2500 ×g.…”

“…Besides they have been associated with human oesophageal cancer in the Transkei region of South Africa and China, and with neural tube defects (NTD) in South Texas, USA (Lino et al, 2004(Lino et al, , 2006Lerda et al, 2005;Shephard et al, 1996;Stack, 1998). On the basis of toxicological evidence, the International Agency for Research on Cancer (IARC) classified FB 1 as a possible carcinogen to humans, Group 2B (IARC, 2002).…”

“…The first, which studied naturally contaminated maize hybrids from the 1992 crop of Agricultural School of Coimbra (Doko et al, 1995), revealed a frequency of contamination of 100%. Lino et al (2006) concluded that 45% of the maize and maize-based samples of the central zone of Portugal were contaminated with FB 1 and FB 2 .…”

Estimation of dietary intakes of fumonisins B1 and B2 from conventional and organic corn

“…In the neighbouring Portugal, fumonisins were detected in 45% of 31 samples of corn and corn-based foods at mean concentrations ranging from 64 to 995 ng/g (Lino, Silva, Pena, & Silveira, 2006). According to data from Portuguese Food Balance, maize consumption in 2003 reached 27.9 g per person per day, and the authors calculated that the estimated daily intake of fumonisins was 0.14 g/kg body weight (7% PMTDI).…”