One-step automatic sample pretreatment for rapid, simple, sensitive, and efficient determination of aflatoxin M1 in milk by immunomagnetic beads coupled to liquid chromatography-tandem mass spectrometry

Application of QuEChERS for Analysis of Contaminants in Dairy Products: A Review

The safety of dairy products is intrinsically linked to consumer health, and the exceedance of risk indicators, such as pesticide and veterinary drug residues, constitutes one of the primary issues affecting their quality and safety. To assess the safety of dairy products, it is crucial to develop accurate and reliable analytical methods for their detection. Food safety testing involving important indicators such as pesticide residues, veterinary drug residues, mycotoxins, and unapproved additives has become a pivotal requirement in the industry field. The QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) method is widely acknowledged as a food safety analysis method currently. This method can effectively extract a wide range of compound classes from diverse matrices in food safety testing, thereby enhancing the accuracy of detection. Additionally, when combined with chromatographic-mass spectrometry techniques, it can simultaneously analyze hundreds of target analytes, rendering it widely applicable in the quality and safety testing of dairy products. Although QuEChERS has rapidly developed in the field of dairy product quality and safety analysis due to its efficiency and speed advantages, certain shortcomings remain, presenting considerable room for improvement. This paper presents a comprehensive review of the utilization and research advancements of the QuEChERS technique in dairy products, with the aim of providing more precise, expeditious, and reliable methods for the safety assessment of dairy products.

Fluorescence immunochromatographic assay for deoxynivalenol using immunomagnetic bead purification

Deoxynivalenol (DON) contaminates various complex matrices, necessitating straightforward, effective cleanup and precise detection methods. This study employed immunomagnetic beads for sample purification and utilized a competitive time-resolved fluoro-immuno-chromatographic assay to achieve quantitative detection of DON in corn and its by-products. The limits of detection and quantification were 104 μg/kg and 243 μg/kg, respectively. Significant cross-reactivity was absent with most common toxins, except for 3-acetyl-deoxynivalenol, which exhibited a cross-reaction rate of 3167%. The recovery rates ranged from 86% to 117%, with coefficients of variation between 6.9% and 9.5%. The correlation coefficient with HPLC was 0.977. This method is rapid, accurate, and requires no large-scale equipment, facilitating on-site detection directly.

Development of an automated immunologic mass spectrometry (iMS) method to overcome matrix effect for quantification: Steroid hormones as the example

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) shows great promise in clinical application for its high specificity, high sensitivity and wide linear range for the determination of small molecules. However, its application in clinical laboratory is hampered by matrix effect of clinical samples which could greatly affect quantification accuracy and the difficulty to be automated for the traditional sample preparation procedures. Thus, new techniques which could achieve selective enrichment to minimize matrix effect and automatic sample preparation of mass spectrometry are needed. We developed an immunologic mass spectrometry (iMS) method to overcome matrix effect and its clinical application was demonstrated for automatic analysis of testosterone (T), progesterone (P) and estradiol (E2) in human serum simultaneously. Firstly, three monoclonal antibodies were coupled to magnetic beads for selective enrichment of target hormones from serum. The immunomagnetic beads were separated, washed and eluted automatically for LC-MS/MS analysis. Analytical performance of the iMS method was validated and compared with traditional LC-MS/MS and chemiluminescence immunoassay (CLIA). Hormone levels were measured for 160 pregnancy women at different gestational weeks. Results showed that target hormones could be selectively captured with absolute recoveries of 93.9%-110.8 %. Relative responses for high, medium and low concentrations of the hormones between serum and methanol solution were 98.0%-109.7 %, 92.2%-105.3 % and 91.7%-96.0 % for T, P and E2, respectively. Calibration curves prepared in methanol solution, BSA solution and blank serum showed good consistency for the iMS method. The automated iMS method could overcome matrix effect of LC-MS/MS and cross-reaction of CLIA. Matrix effect of the iMS method was negligible as high specificity of target hormone enrichment before LC-MS/MS analysis. Matrix-matched calibration standards were no longer necessary for accurate quantification, which was of great benefit for the clinical application of mass spetrometry.

Ratiometric fluorescence and absorbance dual-model immunoassay based on 2,3-diaminophenazine and carbon dots for detecting Aflatoxin B1

In this work, a dual-model immunoassay for detecting Aflatoxin B1 (AFB1) was developed based on 2,3-diaminophenazine (DAP) and carbon dots (CDs). Under the catalysis of horseradish peroxidase (HRP), the o-phthalylenediamine (OPD) was oxidized to DAP which had a yellow color and intense fluorescence. The color changes form colorless to yellow was used to design absorbance model immunoassay. Meanwhile, the absorption spectrum of DAP overlapped with the emission spectrum of CDs which caused the fluorescence of CDs to be quenched. The fluorescence changes of DAP and CDs were used to develop ratiometric fluorescence immunoassay. The dual-model immunoassay showed excellent sensitivity with the limits of detection (LODs) of 0.013 ng/mL for fluorescence mode and 0.062 ng/mL for absorbance mode. Meanwhile, both models exhibited great selectivity for AFB1. Additionally, the recovery rates suggested the proposed dual-model immunoassay had great potential in actual samples detection.

Multiple Isothermal Amplification Coupled with CRISPR-Cas14a for the Naked-eye and Colorimetric Detection of Aflatoxin B1

Aflatoxin B1 (AFB1) is highly toxic and challenging to remove, posing significant risks to both human health and economic development. Therefore, there is an urgent need to develop rapid, simple, and sensitive detection technologies. In this study, we introduce a naked-eye and colorimetric method based on multiple isothermal amplifications coupled with CRISPR-Cas14a and investigate its biosensing properties. This technique utilizes composite nanoprobes (MAPs) comprising magnetic nanoparticles and gold nanoparticles. AFB1 is efficiently identified through an aptamer competition process facilitated by magnetic nanoparticles , which triggers multiple isothermal amplification. This converts trace amounts of the toxin into a large quantity of DNA signal. Upon specific activation of the CRISPR-Cas14a complex, the MAPs are cleaved, resulting in significant changes in both color and colorimetric signal. The method demonstrates acceptable sensitivity, with a detection limit of 31.90 pg mL-1 and a wide detection range from 0.05 to 10 ng mL-1. Furthermore, the assay exhibits satisfactory specificity and high accuracy when it is applied to practical samples. Our approach offers a universal sensing platform with potential applications in food safety, environmental monitoring, and clinical diagnostics.

Microextraction of essential oils: A review

Liquid phase microextraction (LPME) and solid phase microextraction (SPME) are popular extraction techniques for sample preparation due to their green and highly efficient single-step extraction efficiency. With the increasing attention to essential oils, their evaluation and analysis are significant in analytical sciences. In this review, starting from a brief description of the recent advances in the last decade, the attention has been focused on the up-to-date research works and applications based on liquid and solid phase microextraction for essential oil analyses. Particular attention has been given to the approaches using ionic liquids, eutectic solvents, gas flow assisted, and novel composite materials. In the end, the technological convergence of novel microextraction of essential oils in the future has been prospected.

Bio-based material-edible rosemary induced biodegradation of aflatoxin B1 via altering endogenous protective enzymes signatures in animal-derived foods

Aflatoxin B1 (AFB1) is the most hazardous mycotoxin, posing risks to public health. Utilization of bio-based materials to biodegrade AFB1 is a green strategy to overcome this issue. The investigation aimed to screen for endogenous protective enzymes in bio-based material-edible rosemary based on ultra-high performance liquid chromatography coupled to hybrid quadrupole-Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS)-proteomics and ascertain their impacts on the biodegradation and biotransformation of AFB1, and the trade-offs of multilevel metabolism of the animal-derived foods through untargeted metabolomics. The proteomics results verified that bio-based material-edible rosemary (0.20%, w/w) significantly up-regulated glutathione S-transferase and stimulated the down-regulation of cytochrome P450 1A2 levels via activating AhR nuclear translocation in rosemary-pickled AFB1-contaminated goat meat. Metabolomics results demonstrated that edible rosemary substantially increased histidine and glutathione implicated in the antioxidant status of goat meat. More importantly, edible rosemary with high endogenous protective enzyme content could efficiently biodegrade AFB1 in goat meat. We first unveiled that rosemary could not only efficiently biodegrade AFB1 up to 90.20% (20.00-1.96 μg kg^-1) but also elevate the bio-ingestion quality of goat meat. These findings suggest that the bio-based material-rosemary is an efficient and environmentally friendly approach for biodegrading AFB1 and elevating the bio-ingestion composition of goat meat.

Is chemical analysis suitable for detecting mycotoxins in agricultural commodities and foodstuffs?

The assessment of the risks of mycotoxins to humans through consuming contaminated foods resulted in specific legislation that evaluates the presence, quantities, and type of mycotoxins in agricultural commodities and foodstuffs. Thus, to ensure compliance with legislation, food safety and consumer health, the development of suitable analytical procedures for identifying and quantifying mycotoxins in the free or modified form, in low-concentration and in complex samples is necessary. This review reports the application of the modern chemical methods of analysis employed in mycotoxin detection in agricultural commodities and foodstuffs. It is reported extraction methods with reasonable accuracy and those present characteristics according to guidelines of Green Analytical Chemistry. Recent trends in mycotoxins detection using analytical techniques are presented and discussed, evaluating the robustness, precision, accuracy, sensitivity, and selectivity in the detection of different classes of mycotoxins. Sensitivity coming from modern chromatographic techniques allows the detection of very low concentrations of mycotoxins in complex samples. However, it is essential the development of more green, fast and more suitable accuracy extraction methods for mycotoxins, which agricultural commodities producers could use. Despite the high number of research reporting the use of chemically modified voltammetric sensors, mycotoxins detection still has limitations due to the low selectivity from similar chemical structures of mycotoxins. Furthermore, spectroscopic techniques are rarely employed due to the limited number of reference standards for calibration procedures.

Zanthoxylum bungeanum as a natural pickling spice alleviates health risks in animal-derived foods via up-regulating glutathione S-transferase, down-regulating cytochrome P450 1A

Endogenous aflatoxin B1 (AFB1) was quantified in five hundred and forty Hengshan goat meat samples (0.00 ± 23.09 μg kg^-1). Zanthoxylum bungeanum (Z. bungeanum), as a natural pickling spice, can ameliorate the flavor of animal-derived food (goat meat). Yet, considering the direct administration of Z. bungeanum in AFB1-contaminated goat meat, the degradation mechanisms of AFB1 remain elusive. Here, UHPLC-Q-Orbitrap HRMS-based integrative metabolomics (LOQ: 1.74-59.54 μg kg^-1) and proteomics analyses were executed to determine the effects of Z. bungeanum in the biotransformation of AFB1. Z. bungeanum (1.50 %, w/w) application mediated the metabolism of xenobiotics by cytochrome P450, significantly down-regulated cytochrome P450 1A and stimulated the up-regulation of glutathione S-transferase levels in AFB1-contaminated goat meat, leading to degradation of AFB1 (20.00-3.39 μg kg^-1). Metabolomics assays indicated that Z. bungeanum up-regulated l-histidine (1.43-2.21 mg kg^-1) and l-arginine, manifesting potential applications for the contribution of Z. bungeanum to the nutritional value of goat meat.

Multicolor Visual Detection of Deoxynivalenol in Grain Based on Magnetic Immunoassay and Enzymatic Etching of Plasmonic Gold Nanobipyramids

In this study, a multicolor visual method based on a magnetic immunoassay and enzyme-induced gold nanobipyramids (Au NBPs) etching was developed for deoxynivalenol (DON) detection. The magnetic beads modified with high affinity DON monoclonal antibodies were used as a carrier for target enrichment and signal transformation and the Au NBPs with excellent plasmonic optical properties were served as enzymatic etching substrates. The oxidation state TMB, which was generated through catalysis of horseradish peroxidase (HRP), induced the etching of plasmonic Au NBPs, resulting in the longitudinal peak blue-shift of local surface plasmon resonance (LSPR). Correspondingly, Au NBPs with various aspect ratios displayed a variety of individual colors which were visualized by the naked eye. The LSPR peak shift was linearly related to the DON concentration in the range of 0~2000 ng/mL and the detection limit was 57.93 ng/mL. The recovery for naturally contaminated wheat and maize at different concentrations ranged from 93.7% to 105.7% with a good relative standard deviation below 11.8%. Through observing the color change in Au NBPs, samples with overproof DON could be screened preliminarily by the naked eye. The proposed method has the potential to be applied in on-site rapid screening of mycotoxins in grain. In addition, the current multicolor visual method only used for the simultaneous detection of multiple mycotoxins is in urgent need of a breakthrough to overcome the limitation of single mycotoxin detection.

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.

Development of a Novel Magnetic-Bead-Based Automated Strategy for Efficient and Low-Cost Sample Preparation for Ochratoxin A Detection Using Mycotoxin–Albumin Interaction

The mycotoxin ochratoxin A (OTA) is toxic to humans and frequently contaminates wine and beer. Antibodies are essential recognition probes for the detection of OTA. However, they have several drawbacks, such as high costs and difficulty in preparation. In this study, a novel magnetic-bead-based automated strategy for efficient and low-cost OTA sample preparation was developed. Human serum albumin, which is an economical and stable receptor based on the mycotoxin–albumin interaction, was adapted and validated to replace conventional antibodies to capture OTA in the sample. Ultra-performance liquid chromatography–fluorescence detection was used in combination with this preparation method for efficient detection. The effects of different conditions on this method were investigated. The recovery of OTA samples spiked at three different concentrations ranged from 91.2% to 102.1%, and the relative standard deviations (RSDs) were 1.2%–8.2% in wine and beer. For red wine and beer samples, the LODs were 0.37 and 0.15 µg/L, respectively. This reliable method overcomes the drawbacks of conventional methods and offers significant application prospects.

Development and Validation of an Automated Magneto-Controlled Pretreatment for Chromatography-Free Detection of Aflatoxin B1 in Cereals and Oils through Atomic Absorption Spectroscopy

A chromatography-free detection of aflatoxin B1 (AFB1) in cereals and oils through atomic absorption spectroscopy (AAS) has been developed using quantum dots and immunomagnetic beads. A magneto-controlled pretreatment platform for automatic purification, labeling, and digestion was constructed, and AFB1 detection through AAS was enabled. Under optimal conditions, this immunoassay exhibited high sensitivity for AFB1 detection, with limits of detection as low as 0.04 μg/kg and a linear dynamic range of 2.5–240 μg/kg. The recoveries for four different food matrices ranged from 92.6% to 108.7%, with intra- and inter-day standard deviations of 0.7–6.3% and 0.6–6.9%, respectively. The method was successfully applied to the detection of AFB1 in husked rice, maize, and polished rice samples, and the detection results were not significantly different from those of liquid chromatography-tandem mass spectrometry. The proposed method realized the detection of mycotoxins through AAS for the first time. It provides a new route for AFB1 detection, expands the application scope of AAS, and provides a reference for the simultaneous determination of multiple poisonous compounds (such as mycotoxins and heavy metals).