Separation of aflatoxin B1 from synthetic physiological fluids using talc and diatomite: Kinetic and isotherm aspects

Aflatoxins: Source, Detection, Clinical Features and Prevention

The most potent mycotoxin, aflatoxins are the secondary metabolite produced by fungi, especially Aspergillus, and have been found to be ubiquitous, contaminating cereals, crops, and even milk and causing major health and economic issues in some countries due to poor storage, substandard management, and lack of awareness. Different aspects of the toxin are reviewed here, including its structural biochemistry, occurrence, factors conducive to its contamination and intoxication and related clinical features, as well as suggested preventive and control strategies and detection methods.

Oxygen Free Radical Scavenger PtPd@PDA as a Dual-Mode Quencher of Electrochemiluminescence Immunosensor for the Detection of AFB1

Here, a dual-mode quenched electrochemiluminescence (ECL) immunosensor based on PtPd@PDA was proposed. Among them, nitrogen-doped hydrazide conjugated carbon dots (NHCDs), as an ECL emitter and a donor of resonance energy transfer, were quenched by PtPd@PDA (receptor). At the same time, PDA in PtPd@PDA, as an oxygen radical scavenger, completed the further quenching of the ECL signal by consuming O₂^•- generated by the decomposition of co-reactant H₂O₂. The dual-mode quenching from the above two channels was achieved. In addition, compared with the traditional carbon quantum dots, NHCDs as ECL emitters had lower excitation potential. Moreover, a large number of amino groups provided by aminated MWCNTs could capture more antibodies while connecting with NHCDs. Under the optimum experimental conditions, taking aflatoxin B1 as the target, the proposed sensor with good specificity, stability, and reproducibility had good linearity when the concentration of AFB1 was 0.01-100 ng/mL, with the detection limit of 2.63 pg/mL (S/N = 3). This strategy provided more possibilities for the application of dopamine metal nanocomposites in electrochemiluminescence analysis and offered a new approach to detect AFB1.

Obtention of biochar-Ca nanoparticles using Citrus tangerina׃ A morphological, surface and study remotion of Aflatoxin AFB1

This work presents the formation of biochar with calcium nanoparticles (NPsCa) in function of pyrolysis time (C10, C30, C60, C120 and C180 min) using the Citrus tangerina peel and their evaluation in the remotion of Aflatoxin B1 (AFB1) in aqueous phase. Firstly, the Citrus tangerina was studied by Thermogravimetric analysis to determine the optimal temperature (TGA), obtaining a result of 600 °C. The biochar (NPsCa) were characterized by Scanning Electronic Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), as well as surface properties including the identification of functional groups by Fourier Transform Infrared Spectrometry (FTIR), and energetic states through the X-Ray Photoelectron Spectroscopy (XPS). The adsorption studies were carried out on the different materials and later, the experimental data was adjusted to different mathematical models, obtaining the best fit of the kinetic data to the Ho-McKay model, whilst the adsorption isotherms were adjusted to the model of Langmuir, which indicates that the Aflatoxin B1 adsorption process is carried out through a monolayer chemisorption process with maximum sorption capacities (qm) ranging between 15.72 and 63.22 μg g^-1 with the 180th minute being the adequate time to obtain the carbon with the best surface properties and the best adsorption capacity. Additionally, it was observed that each material can be reused up to five times in accordance with the results from the reuse cycles.

Adsorption of deoxynivalenol by pillared montmorillonite

Deoxynivalenol (DON) is found widely in foods and feeds that are contaminated with mildew and is one of the most harmful mycotoxins, threating not only human health but also impacting animal husbandry. Various physical, chemical and biological detoxification strategies have been applied in the past to reduce mycotoxin contamination. As a practical and economic method, addition of montmorillonite (Mt) offers the potential to eliminate mycotoxins, especially aflatoxin B1 (AFB₁) and zearalenone (ZEA). Our study aimed to control DON, for the first time, using environmentally friendly Mt, modified with aluminum, iron and titanium via a pillaring effect to enlarge interlayer spacing. The materials were characterized using XRD, FTIR, SEM, EDS and BET. Spacing of the pillared Mt layers was shown to exceed that of raw Mt and could be tuned using the pillaring reagents (Al, Fe and Ti, 0.01 to 2.00 eq. relative to the cation exchange capacity of Mt). Adsorption of DON by pillared Mt was investigated using UPLC-MSMS (at pH 2.0 and 6.8). The results demonstrated that the adsorption ratios of 1.00-Al-Mt, 0.50-Fe-Mt and 1.00-Ti-Mt were 23.6%, 14.7% and 23.4%, respectively at pH 2.0 and 27.1%, 21.8%, and 27.4% correspondingly at pH 6.8 when added at 1.0 mg, which is 3-4 times higher than raw Mt (6.3-6.8% at pH 2.0 and 7.3-8.1% at pH 6.8). It was also found that with increased addition of pillared Mt (2.5 mg), the adsorption ratio approached 35%. The time for reaching equilibrium was approximately 120 min. These results demonstrated that Mt after pillaring modifications with Al, Fe and Ti can have potential for the control of DON in foods and feeds.

Functionalized nanoflower-like hydroxyl magnesium silicate for effective adsorption of aflatoxin B1

Aflatoxin B1 (AFB1), which is widely found in food and feed, poses a serious threat to the health of human and livestock. In this work, functionalized nanoflower-like hydroxyl magnesium silicate (FNHMS) was synthesized for adsorption of AFB1. First, bulk magnesium silicate (MS) was converted into nanoflower-like hydroxyl magnesium silicate (NHMS) by hydroxylation. Cetyltrimethylammonium bromide (CTMAB) modification then enhanced the hydrophobicity and the affinity to AFB1 of NHMS. The adsorption performance for AFB1 followed the order of MS < NHMS < FNHMS, and the adsorption performance increased with the increase of the dose of CTMAB. Isothermal adsorption analysis indicated that the surface of FNHMS was heterogeneous. The adsorption capacity of FNHMS-0.4 to AFB1 was estimated to be 27.34 mg g^-1 and 28.61 mg g^-1 by Freundlich and Dubinin-Radushkevich isotherm adsorption model, respectively. By analyzing the adsorption kinetics and adsorption thermodynamics, both physical adsorption and chemisorption existed in the process of AFB1 being adsorbed on FNHMS-0.4. Adsorption mechanisms analysis indicated that the adsorption followed the adsorption site priority of H > O > Mg. This work demonstrates that FNHMS could be a promising adsorbent for removal of AFB1.

Simultaneous detoxification of polar aflatoxin B1 and weak polar zearalenone from simulated gastrointestinal tract by zwitterionic montmorillonites

The current research focuses on the development of novel mycotoxins adsorbents using zwitterionic surfactants modified montmorillonites (ZMts) for simultaneous removal of highly health-hazardous polar aflatoxin B₁ (AFB₁) and low polar zearalenone (ZER). Two types of ZMts including dodecyl dimethyl betaine (BS-12) and lauramidopropyl betaine (LAB-35) modified montmorillonites (BS-12/Mts and LAB-35/Mts) were fabricated, and the structural, interfacial and textural features of which were explored by different techniques. It is indicated that ZMts have different structural configurations based on the surfactant type and loadings, convert from hydrophilic to hydrophobic property, with a mesoporous network inherited from Mt. The resultant adsorbents show significant improvements on the detoxification efficiency of both AFB₁ and ZER. pH has little effect on the adsorption of ZMts, suggesting no desorption happens. The adsorption mechanisms of raw Mt, BS-12/Mts and LAB-35/Mts to AFB₁ and ZER were proposed based on the characterizations and adsorption isotherms. This study demonstrates that ZMts possess simultaneous detoxification functions to mycotoxins with different polarities, and provides new insights into development of versatile mycotoxins adsorbents.

Evaluation of nonionic surfactant modified montmorillonite as mycotoxins adsorbent for aflatoxin B1 and zearalenone

This work aims at exploring the potential of nonionic surfactant octylphenol polyoxyethylene ether (OP-10) modified montmorillonites (NMts) as mycotoxins adsorbent. The resulting NMts has different structural configurations, organic carbon contents, surface hydrophobicity and textural properties at different surfactant loadings. The prepared NMts were used for adsorption of polar aflatoxin B₁ (AFB₁) and weak polar zearalenone (ZER) in both single and binary-contaminate systems by simulating conditions of gastrointestinal tract. The adsorption capacities of NMts to AFB₁ and ZER increased up to 2.78 and 8.54 mg/g respectively from 0.51 and 0.00 mg/g of raw montmorillonite (Mt). High adsorption capacities of NMts to AFB₁ and ZER could be reached at low surfactant loadings. There was little decrease from pH of 3.5 to 6.5 but became negligible with increasing the surfactant loadings. In binary-contaminate adsorption system, the adsorption of ZER was obviously affected by the existence of AFB₁, while ZER had little effect on the adsorption process of AFB₁ due to different adsorption mechanism. This study demonstrates that NMts could be a promising adsorbent for simultaneous detoxification of polar and non-polar mycotoxins.