Extraction without Organic Solvents in the Determination of Fumonisins B1, B2, and B3 in Maize by HPLC–FLD and ELISA Tests

Rapid colorimetric sensor for ultrasensitive and highly selective detection of Fumonisin B1 in cereal based on laccase-mimicking activity of silver phosphate nanoparticles

Ag3PO4 nanoparticles (NPs) was prepared through a facile coprecipitation method, and was first found to have excellent laccase-mimicking catalytic activity. The study confirms that Fumonisin B1 (FB1) can effectively hinder the production of superoxide anion (O2-) between Ag3PO4 NPs and dissolved oxygen, and further inhibit laccase-mimicking activity of Ag3PO4 NPs. Thus, a novel rapid colorimetric sensor for FB1 analysis in cereal was first established using laccase-mimicking activity as sensing signal. The absorbance variation of sensing solution is directly related to the amount of FB1, and the color change is further combined with smartphone for quantitively analysis of FB1. The limit of detection (LOD) of the sensor is determined as low as 1.73 μg·L-1, which is far lower than the maximum residue limits (MRLs) of FB1 set by European Commission and US Food and Drug Administration (FDA). The average recovery of 87.8-104.5% for FB1 detection was obtained in cereal.

Well-oriented immobilized immunoaffinity magnetic beads for detection of fumonisins in grains and feeds via pre-column automatic derivatization of high-performance liquid chromatography

In this study, based on the high-throughput automatic sample pretreatment with immunoaffinity magnetic beads with oriented immobilized antibodies, grain and feed fumonisin (FB) content was detected using pre-column automatic derivatization of high-performance liquid chromatography (HPLC). The FB capacity of well-oriented antibody immunoaffinity magnetic beads was 1.5-1.8 times that of magnetic beads with randomly fixed antibody. This pre-column automatic derivatization method using an autosampler can reduce error from manual injection and improve detection efficiency. The spiked recoveries for three different concentrations in maize, husked rice, and pig feed under optimized conditions were 84.6-104.0% (RSD < 9.3%). Our novel method was also applied to the analysis of FBs in 63 maize samples collected from the main maize-production regions in China. The results showed that as latitude increased, the contamination level of FBs tended to decrease. High temperature and high humidity are also more favorable for FB growth.

UV-induction of photolytic and photocatalytic degradation of fumonisins in water: reaction kinetics and toxicity

Although fumonisins are toxic and carcinogenic mold products that contaminate feed, food, and water, their photodegradation has not yet been reported. In this work, the efficiency of photolysis (UV, UV/H₂O₂, and UV/[Formula: see text]) and photocatalysis (TiO₂ (Degussa P25/Wackherr) and ZnO) for the degradation of fumonisins in an aqueous medium were investigated. In the case of fumonisin B₁ (FB₁) optimal conditions in terms of pH, the initial concentrations of H₂O₂/[Formula: see text] for UV, UV/H₂O₂, and UV/[Formula: see text] treatments were investigated. The photocatalytic degradation using TiO₂ Wackherr as catalyst at natural pH (about 8) proved to be the most efficient treatment for removal of FB₁ and FB₃. Namely, during the first 30 min of irradiation, 99% of FB₁ (1.39 μM) was degraded, while FB₃ (0.425 μM) was completely removed during the first 20 min of irradiation. In the case of FB₂ (0.687 μM), UV/[Formula: see text] was the most efficient treatment, and complete removal occurred in the first 90 min of irradiation. All applied treatments for fumonisins removal have followed pseudo-first-order kinetics under the relevant experimental conditions. Toxicity of fumonisins and their mixtures formed during photodegradation were investigated using mammalian cell lines (BHK, H-4-II-E, Neuro-2a, and MRC-5). The BHK cell line was the most sensitive to fumonisins, especially FB₂ and FB₃, and its photodegradation mixtures.

Rapid determination of fumonisin (FB1) by syringe SPE coupled with solid-phase fluorescence spectrometry

Fumonisin B₁ is the most prevalent member of a family of toxins, known as fumonisins, which occurs mainly in maize, wheat and other cereals. Due to its hepatotoxic and nephrotoxic in all animal species, very strict regulations have been imposed on the levels of fumonisin B₁ in cereal and cereal-based foods worldwide. In this work, a rapid determination method of fumonisin B₁ by membrane solid phase extraction coupled with solid-phase fluorescence analysis is developed. A rhodamine based fluorescent probe was used for derivatization with fumonisin B₁. After derivatization and extraction by nylon membrane, the enriched fumonisin B₁ can be detected directly on the membrane without further elution process that is placed in a designed spectra collection device. The established method showed a linear relationship in concentration range of 0.5-5.0 μg/L, with the R² = 0.991, and a limit of detection of 0.119 μg/L. Method accuracy was further confirmed using LC-MS method by comparing the detection results of 3 corn powder samples spiked with FB₁, that demonstrated equivalent results. The results of this study indicated that the proposed method was simple, sensitive, reliable and suitable for trace fumonisins B₁ quantitation in corn-based feeds.

Effects of pH and Temperature on the Stability of Fumonisins in Maize Products

This paper is a study of the stability of fumonisins in dough based on maize flour prepared in a phosphate buffer with a pH of 3.5, 5.5 or 7.5 and baked at a temperature within the range of 100-250 °C. Buffers with various pH values were tested, since it is well-known that pH may significantly influence interactions of fumonisins with other substances. A standard analytical procedure was used to determine the concentration of free fumonisins. Hydrolysis in an alkaline medium was then applied to reveal the hidden forms, while the total fumonisins concentations was determined in another measurement. The total concentration of fumonisins was statistically higher in pH = 3.5 and pH = 5.5 than the concentration of free fumonisins; no similar difference was found at pH = 7.5. The applied phosphate buffer pH 7.5 may enhance solubility of fumonisins, which would increase extraction efficiency of free analytes, thereby decreasing the difference between concentrations of total and free fumonisins. Hydrolysed B₁ fumonisin (HFB₁) and partially hydrolysed B₁ fumonisin (isomers a and b: PHFB1a and PHFB1b, respectively) were the main investigated substances. For baking temperatures below 220 °C, fumonisins were slightly more stable for pH = 5.5 than for pH = 3.5 and pH = 7.5. In both of these latter cases, the concentration of partially hydrolysed fumonisins grew initially (up to 200 °C) with an increase in the baking temperature, and then dropped. Similar behaviour was observed for free HFB₁, which may suggest the following fumonisin degradation mechanism: initially, the tricarballylic acid (TCA) groups are removed from the molecules, and next, the HFB₁ molecules disintegrate.