Rapid purification method for fumonisin B1 using centrifugal partition chromatography

Separation of ochratoxins by centrifugal partition chromatography

The present research work was dedicated to developing an efficient method based on liquid-liquid chromatography (centrifugal partition chromatography, CPC) applicable to routine purifications of ochratoxins (OT) from the liquid culture of the strain A. albertensis SZMC 2107. The crude extract contained numerous components in addition to OTA (90.1 %,) and OTB (1.1 %,) according to HPLC examinations. For the separation of OTs by CPC, several tertiary systems based on acetonitrile, acetone, and short-chain alcohols were examined to find the most applicable biphasic system. The hexane/i-propanol/water 35:15:50 system supplemented with 0.1 % acetic acid was found to be the most efficient for use in CPC separation. Using liquid-liquid instrumental separation, the two OTs, namely OTA (2.23 mg) and OTB (0.031 mg), were successfully isolated with 96.3 % and-72.8 % purity, respectively, from 1 L ferment broth. The identities and purities of the purified components were confirmed and the performance parameters of each separation step and the whole procedure were determined. The developed method could be used effectively to purify OTs for analytical or toxicological applications.

Scale-up of Aflatoxin Purification by Centrifugal Partition Chromatography

Aflatoxins (AFs) are a group of secondary metabolites that cause several diseases in both animals and humans. Since the discovery of this group of toxins, several effects were revealed, such as hepatic changes, carcinoma, failure, and cancer of the liver. In the European Union, there are concentration limits for this group of mycotoxins in food and feed products; thus, these substances are required in their pure forms to prepare reference standards or certified reference materials. In our present work, a liquid–liquid chromatographic method utilizing a toluene/acetic acid/water ternary system was improved. In order to enhance the purification and gain a higher amount of pure AFs in one separation run, a scale-up of the previous separation was carried out. In several scale-up steps—including the determination of the maximum concentration and volume to load on a 250 mL rotor via a loop and via a pump as well, and the quadruplication of the entire separation procedure to a 1000 mL rotor—an efficient scale-up was achieved. Utilizing a 250 mL rotor in an 8-hour workday, altogether approximately 2.2 g of total AFs could be purified with 8.2 liters of solvent, while on a 1000 mL column, approximately 7.8 g AFs could be prepared, utilizing around 31 liters of solvents.

Preparative isolation and purification of B-type fumonisins by using macroporous resin column and high-speed countercurrent chromatography

B-type fumonisins (FBs) are water-soluble mycotoxins produced by Fusarium species, which are mainly found in maize products and threaten food safety. Toxicological studies and quantitative determinations of fumonisins require large amounts of pure toxins, and their high prices limit progress in FBs research. In this study, we used a macroporous resin column combined with high-speed countercurrent chromatography to separate large quantities of FBs. A fermented rice culture was extracted with 75% methanol. The dynamic adsorption capacity of FBs on XAD-2 resin was 27.5 mg/g resin at 25°C, pH 4.0, and then the FBs were desorbed with 60% methanol. The crude FBs were further purified using a biphasic system consisting of n-heptane/n-butanol/methanol/water (2:4:1:4, v/v/v/v). The method yielded 1.55 g of FB1 and 0.55 g of FB3 with purities of 96.8% and 95.6%, respectively, from 1 kg of rice culture, and the final overall yield of FBs was 74.8%.

Separation and Purification of Aflatoxins by Centrifugal Partition Chromatography

Aflatoxins are mycotoxins that are produced by several species of filamentous fungi. In the European Union, the concentration limits for this group of mycotoxins in food and feed products are very low (on the order of parts per billion). Thus, relatively high amounts of these substances in their pure forms are required as reference standards. Chromatographic techniques based on solid stationary phases are generally used to purify these molecules; however, liquid–liquid chromatographic separations may be a promising alternative. Therefore, this study proposes a liquid–liquid chromatographic method for the separation of four aflatoxins and impurities. To optimise the method, numerous biphasic solvent systems (chloroform-, acetone- and acetic acid-based systems) were tested and evaluated in terms of their effectiveness at partitioning aflatoxins; the toluene/acetic acid/water (30:24:50, v/v/v/%) system was found to be the most efficient for application in centrifugal partition chromatographic instrument. Using liquid–liquid instrumental separation, the four aflatoxins, namely B₁ (400 mg), B₂ (34 mg), G₁ (817 mg) and G₂ (100 mg), were successfully isolated with 96.3%–98.2% purity from 4.5 L of Aspergillus parasiticus fermented material in a 250 mL centrifugal partition chromatography column. The identities and purities of the purified components were confirmed, and the performance parameters of each separation step and the whole procedure was determined. The developed method could be effectively used to purify aflatoxins for analytical applications.

Appropriateness to set a group health-based guidance value for fumonisins and their modified forms

The EFSA Panel on Contaminants in the Food Chain (CONTAM) established a tolerable daily intake (TDI) for fumonisin B1 (FB 1) of 1.0 μg/kg body weight (bw) per day based on increased incidence of megalocytic hepatocytes found in a chronic study with mice. The CONTAM Panel considered the limited data available on toxicity and mode of action and structural similarities of FB 2-6 and found it appropriate to include FB 2, FB 3 and FB 4 in a group TDI with FB 1. Modified forms of FBs are phase I and phase II metabolites formed in fungi, infested plants or farm animals. Modified forms also arise from food or feed processing, and include covalent adducts with matrix constituents. Non-covalently bound forms are not considered as modified forms. Modified forms of FBs identified are hydrolysed FB 1-4 (HFB 1-4), partially hydrolysed FB 1-2 (pHFB 1-2), N-(carboxymethyl)-FB 1-3 (NCM-FB 1-3), N-(1-deoxy-d-fructos-1-yl)-FB 1 (NDF-FB 1), O-fatty acyl FB 1, N-fatty acyl FB 1 and N-palmitoyl-HFB 1. HFB 1, pHFB 1, NCM-FB 1 and NDF-FB 1 show a similar toxicological profile but are less potent than FB 1. Although in vitro data shows that N-fatty acyl FBs are more toxic in vitro than FB 1, no in vivo data were available for N-fatty acyl FBs and O-fatty acyl FBs. The CONTAM Panel concluded that it was not appropriate to include modified FBs in the group TDI for FB 1-4. The uncertainty associated with the present assessment is high, but could be reduced provided more data are made available on occurrence, toxicokinetics and toxicity of FB 2-6 and modified forms of FB 1-4.

An epimer of deoxynivalenol: purification and structure identification of 3-epi-deoxynivalenol

In an investigation of deoxynivalenol (DON)-transformation products by Devosia mutans 17-2-E-8, the major product was identified as 3-epi-DON. This DON-transformation product was analysed by liquid chromatography and identified by congruent retention time and UV/Vis spectrum, as well as mass spectrometric data. Nuclear magnetic resonance (NMR) experiments including correlation spectroscopy (COSY), heteronuclear single quantum coherence (HSQC) and nuclear overhauser effect (NOE) were conducted for structural characterisation of 3-epi-DON. High-speed counter-current chromatography (HSCCC) was applied to scale up the separation of 3-epi-DON from DON in a D. mutans 17-2-E-8 culture. From the culture where 100 mg DON was applied, 56 mg of 3-epi-DON (purity of 96.8%) was obtained from the HSCCC. The purified 3-epi-DON will be used for toxicological characterisation studies of this chemical.

Fumonisin measurement from maize samples by high-performance liquid chromatography coupled with corona charged aerosol detector

Fumonisins are a class of mycotoxins produced mainly by Fusarium species, which is primary fungal contaminant of the maize and maize-derived products around the world. The B-series fumonisins (FB1, FB2 and FB3) are the most abundant and toxic constituent; thus, their levels are regulated generally worldwide. In this study, we developed a reliable method for the measurement of fumonisin FB1, FB2 and FB3 mycotoxins from maize samples without the time-consuming derivatization step using a high-performance liquid chromatograph coupled with corona charged aerosol detector. The detection and quantitation limit of the whole method were 0.02 and 0.04 mg/kg for each fumonisins, respectively. The detection linearity was tested in the calibration range of 2 orders of magnitude and the recoveries from the spiked samples were determined. The developed method proved to be sufficient to measure the maximum residue levels of fumonisins, which are specified in European Union and United States in maize and maize-based products.