Validation of a method of high performance liquid chromatography with fluorescence detection for melamine determination in UHT whole bovine milk

A method of high performance liquid chromatography with fluorescence detection (HPLC-Fluo), based on previous studies of the natural fluorescence emission of melamine (250/365 nm), was developed and validated for melamine determination as an adulterant of bovine UHT whole milk. The clean up treatment of milk samples by deproteinization was thoroughly optimized. No matrix effect was observed and a linear range from 0.05 to 10.0 μg mL⁻¹ was obtained, with a value of R² equal to 0.9998. The limits of detection and quantification of melamine were 0.0081 and 0.027 μg mL⁻¹ respectively, or 0.023 and 0.076 μg g⁻¹ of milk, respectively, considering the sample dilution during extraction. Extracts of milk samples fortified with melamine at three concentration levels, two of which corresponded to the levels established by WHO for melamine in foods, led to an overall mean recovery of 95.4 ± 1.2% (n = 9). This recovery value satisfies the performance criteria established by the Codex Alimentarius for analytical methods suitable for determination of food residues, demonstrating the usefulness and effectiveness of the proposed method.     

Donkey's milk safety: POCs and PCBs levels and infant daily intake

In this work 45 donkey milk, 15 forage and 15 feed samples from farms in Sicily, Calabria and Emilia-Romagna were evaluated for the content of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). Analysis was carried out by GC–ECD and GC–MS. The limits of detection (LOD, S/N = 3) were from 0.40 to 1.91 μg L⁻¹ and from 0.16 to 2.11 μg L⁻¹ for the different OCPs and PCBs, respectively. The limits of quantification (LOQ, S/N = 10) were 1.32–6.37 μg L⁻¹ and 0.52–7.53 μg L⁻¹. The results showed few differences among samples of different farms and that contamination is kept at very low and almost always below the maximum residual levels fixed by legislation of 100 ng/g of fat for PCBs, of 0.04 mg/kg for DDTs and 0.006 mg/kg for aldrin with dieldrin (449/1999 and 149/2008). Also in comparison with current values of TDI proposed by European Agencies, the POCs and PCBs daily intakes found in donkey milk were very low for several of samples.     

Aflatoxin M1 in UHT milk consumed in Turkey and first assessment of its bioaccessibility using an in vitro digestion model

Contamination of milk and dairy products with aflatoxin M₁ (AFM₁) continues to receive increased attention because of its potential health hazard to humans. The first aim of this study was to know the occurrence and levels of AFM₁ in whole UHT milk from main processors in Turkey in order to make a preliminary exposure assessment. A total of 40 milk samples were analysed for AFM₁ using high performance liquid chromatography with fluorescence detection (HPLC-FD) after immunoaffinity column clean-up. Aflatoxin M₁ was detected in 20% of samples at levels ranging from <0.004 to 0.076 μg l⁻¹. Only two samples contained AFM₁ above the EU limit of  0.05 μg l⁻¹.The second aim of this study was to determine the bioaccessibility of AFM₁ from milk using an in vitro digestion model. The bioaccessibility of AFM₁ in spiked and naturally contaminated milk samples ranged from 80.5 to 83.8% and from 81.7 to 86.3%, respectively. No difference (P > 0.05) in AFM₁ bioaccessibility was found between spiked and naturally contaminated milk samples. This study also assessed the binding of AFM₁ by six probiotic bacteria under simulated gastrointestinal conditions. A 15.5–31.6% reduction in AFM₁ bioaccessibility was observed in the presence of probiotic bacteria. Based on the results obtained in the present study, the mean daily intake of AFM₁ through milk consumption was estimated as 0.008 ng kg⁻¹ b.w. day⁻¹ for Turkish adults.     

A survey on the occurrence of aflatoxin M1 in raw milk produced in Adana province of Turkey

During 2012, a total of 176 samples of raw milk obtained from dairy plants of Adana province of Turkey were analysed for the presence of aflatoxin M₁ (AFM₁). Aflatoxin M₁ analysis was carried out by centrifugation, liquid–liquid extraction, immunoaffinity column clean-up and high performance liquid chromatography with fluorescence detection (HPLC-FD). The limits of detection (LOD) and quantification (LOQ) of the analytical method were 0.021 μg kg⁻¹ and 0.025 μg kg⁻¹. Accuracy of the method obtained from bias ranged from 2.94 to 8.70. Aflatoxin M₁ was detected in 53 out of 176 samples analysed (30.1%). The ranges for positive samples were 0.042–0.552, 0.033–1.01, 0.047–0.150 and 0.025–0.102 μg kg⁻¹ in autumn, winter, spring and summer seasons, respectively. Thirty samples of raw milk (17%) were above the legal limits of Turkey and EU regulations.     

Aflatoxins occurrence through the food chain in Costa Rica: Applying the One Health approach to mycotoxin surveillance

Aflatoxins (AFs) are toxic metabolites produced by Aspergillus spp. and commonly found in crops, grains, feedstuff, and forages. Exposure to AFs has been associated with increased risk of liver cancer and growth retardation in humans, liver damage, immunosuppression, embryotoxicity in both animals and humans, and decreased milk, egg and meat production in animals. For the first time, the Costa Rican national mycotoxin surveillance programs for animal feed and food are considered as a whole, applying the One Health approach to the mycotoxin epidemiological research. Therefore, the aim of this study was to determine the occurrence of AFs in cereals, nuts, grains intended for animal and human consumption in Costa Rica.In animal feed and feed ingredients, 970 samples were analyzed for AFs from 2010 to 2016 with an overall prevalence of positive samples of 24.0% (ranging from 0.01 to 290 μg kg⁻¹). Only 2.5% of the samples failed to comply the regulation for total AFs (20 μg kg⁻¹ feed). From 5493 samples of agricultural commodities intended for human consumption analyzed from 2003 to 2015, there was an overall prevalence of AF positive samples of 10.8% (ranging from 0.48 to 500 μg kg⁻¹), and 2.8% did not comply the regulation for AFs (20 μg kg⁻¹). In both feed and food, the highest AF prevalence corresponded to corn ingredients (27.8%) and white corn (38.6%), respectively. Among the commodities intended for human consumption, red beans had the highest aflatoxin concentrations (500 μg kg⁻¹).     

Transfer of chloramphenicol from milk to commercial dairy products – Experimental proof

The purpose of the study was to investigate the chloramphenicol (CAP) residue in dairy products after experimental CAP transferring from milk to butter, sour cream, white cheese and whey. In order to determine the CAP residue in dairy products, the new approach for the extraction process was developed. The original, simple and fast analytical method is based on QuEChERS and LC-MS/MS. The homogenized sample was extracted and partitioned after the adding of sodium chloride with acetonitrile. The experiment was conducted to check if CAP is transferred from milk to dairy products, and also to check the extraction of CAP from the different dairy matrices. Average recovery ranged from 97.8 to 102.8% and within-laboratory reproducibility was lower than 8.7%. The suggested method is sensitive, the calculated limit of decision (CCα) was from 0.06 to 0.10 μg kg⁻¹ and detection capability (CCβ) from 0.08 to 0.15 μg kg⁻¹. The results of the experiment (butter 4.86 μg kg⁻¹, sour cream 3.5 μg kg⁻¹, white cheese 2.36 μg kg⁻¹ and whey 0.14 μg kg⁻¹) and validation demonstrated that this method is suitable for determination and confirmation of CAP in a variety of dairy product matrices.     

Occurrence of aflatoxin M1 in pasteurised,UHT milk and milk powder from goat origin

In the present study, 36 samples of pasteurised, ultra-high-temperature (UHT) treated and goat milk powder traded in the city of Campinas, Brazil, were analysed for aflatoxin M₁ (AFM₁), from October to December 2004 and March to May 2005. Results showed 25 (69.4%) positive samples for AFM₁ at levels of 0.011–0.161 μg L⁻¹ of milk, which were below the tolerance limit of 0.500 μg L⁻¹ as adopted for AFM₁ in milk by Brazilian regulations. Mean levels of AFM₁ in pasteurised, UHT and goat milk powder were 0.072 ± 0.048, 0.058 ± 0.044 and 0.056 ± 0.031 μg L⁻¹, respectively. It is concluded that the incidence of AFM₁ in goat milk traded in Campinas is high, but at levels that probably leads to a non-significant human exposure to AFM₁ by consumption of goat milks.     

Development and validation of a new qualitative ELISA screening for multiresidue detection of sulfonamides in food and feed

An indirect competitive enzyme-linked immunosorbent assay (ELISA) to screen sulfonamide residues in food (muscle, eggs, milk and honey) and feed has been developed and validated according to Commission Decision 2002/657/EC. The immunoreagents were appropriately produced to detect a wide range of sulfonamide antibiotic congeners, obtaining half-maximum inhibition concentration (IC₅₀) values below 10 μg L⁻¹ for 11 sulfonamides widely used in veterinary practices. Taking into account the complexity of involved matrices, specific sample preparation protocols have been optimised combining high method throughput with low detectable concentrations. Accordingly, depending on the congener, the obtained detection capabilities (CCβs) were lower or equal to 20 μg kg⁻¹ (muscle, eggs and milk), 10 μg kg⁻¹ (honey) and 2 mg kg⁻¹ (feed). Finally the developed qualitative test was applied to real samples collected within the official monitoring programmes: results exceeding the established screening cut-off were re-analysed with a suitable confirmatory method. The presence of one or more sulfonamides was found in all the suspect screening samples thus demonstrating that the proposed ELISA can be successfully applied in class-specific detection of sulfonamides in food and feed.     

Aflatoxin M1 survey on randomly collected milk powder commercialized in Argentina and Brazil

Aflatoxin M₁ (AFM₁), the main monohydroxylated of aflatoxin B₁ (AFB₁) formed in liver and excreted in the milk, has toxicological proprieties comparable to those of AFB₁, albeit a lower carcinogenic potency. The presence of AFM₁ was investigated in 30 samples of powdered milk purchased in Argentina and Brazil. The samples were analyzed using an immunoaffinity column for cleanup and HPLC-FLD for determining AFM₁. The quantification limit was 0.1 μg/kg. AFM₁ was found in all the samples at levels ranging from 0.1 to 0.92 μg kg⁻¹ with average concentration of 0.39 μg kg⁻¹.     

The seasonal variation of aflatoxin M1 in milk and dairy products and assessment of dietary intake in Punjab,Pakistan

Total 372 samples (169 sample from summer and 203 samples from winter) of milk and dairy products were collected from major cities of Punjab, Pakistan, during 2014–2015. The aflatoxin M₁ (AFM₁) levels were analyzed using HPLC, equipped with floresceⁿce detector. The results have showed that AFM₁ was detected in 77 (45.5%) samples of milk and dairy products from summer at the range of LOD to 229.6 ng/L, and 114 (56.1%) samples from winter at a range of LOD to 345.8 ng/L. The highest mean of AFM₁ i.e. 94.9 ± 5.4 ng/L from summer and 129.6 ± 8.4 ng/L from winter was detected in raw milk samples. The results have shown that 37.5% of milk, 32% of UHT milk, 12.5% of powdered milk, 20% of flavored milk, 20% of yogurt and 16% of flavored milk samples from summer were found exceeded the recommended levels of AFM₁ i.e 50 ng/L (European Union permissible limit), as compared to 38.1%, 37.1%, 15.6%, 21.4%, 27.7% and 40% samples of milk, UHT milk, powdered milk, flavored milk, yogurt and flavored yogurt from winter, respectively. The mean level of AFM₁ in samples of milk, UHT milk and powdered milk samples from winter season has significantly (p˂ 0.05) higher as compared to the mean levels in samples from summer season. The dietary exposures of AFM₁ in milk and dairy products were calculated in five different age groups and the highest level of 3.42 and 3.33 ng/L/day in summer and 4.7 and 4.6 ng/L/day in winter were found in 1–5 years of male and female infants, respectively. The results of present study have shown significant levels of AFM₁ in milk and dairy products from Punjab, Pakistan and could pose considerable thereat to the health of local population.     

A survey of mycotoxins in random street-vended snacks from Lagos,Nigeria, using QuEChERS-HPLC-MS/MS

A survey in African snacks was carried out in order to evaluate the intake of 23 mycotoxins. The African snack samples were purchased from street vendors within Lagos metropolis (Nigeria) and evaluated for the presence of 23 mycotoxins using a modified QuEChERS procedure coupled with liquid chromatography-triple quadrupole linear ion trap mass spectrometer. The snacks included akara, baked coconut, coconut candy, donkwa, groundnut cake (kulikuli), lafun, milk curd (wara), fresh and dried tiger-nuts, and yam flour. Only three mycotoxins were detected in 23.8% of the studied snacks, and at concentrations ranging from 6 to 54 μg kg⁻¹. The concentrations of aflatoxin B₁ (AFB₁) and AFB₂ reached 23 μg kg⁻¹ and 3 μg kg⁻¹, respectively. Moreover a sample of baked coconut contained α-zearalenol (α-ZOL), which was up to 54 μg kg⁻¹ in coconut candy. As considers prevalence, aflatoxins and α-ZOL were not detected in lafun and groundnut-based snacks (donkwa and kulikuli), whereas each of the three mycotoxins contaminated 12.5% (1/8) of the coconut-based samples. This is the first report of α-ZOL in cassava and coconut, and their products. AFB₁ and total aflatoxins (TAFs) concentrations exceeded the maximum allowable limit recommended by National Agency for Food and Drug Administration and Control Nigeria (NAFDAC) in one sample of baked coconut (AFB₁ = 23 μg kg⁻¹ and TAFs = 26 μg kg⁻¹) and donkwa (AFB₁ = 19 μg kg⁻¹ and TAFs = 21 μg kg⁻¹).     

Immunochemical detection of penicillins by using biohybrid magnetic particles

An Enzyme Linked Immunosorbent Assay (ELISA) with the ability to detect some of the most widely used penicillins such as penicillin G, amoxicillin and ampicillin has been developed and validated in milk samples to ensure food safety. The assay can achieve limits of detection (0.1 μg L⁻¹) much lower than the MRLs (Maximum Residue Levels) established by the EU (4 μg L⁻¹). The procedure allows the analysis of the samples with a simple and fast treatment of the matrix with biohybrid magnetic particles to hydrolyze the β-lactam ring. A new immunizing hapten has been described and the polyclonal antibodies produced showed high specificity for open ring penicillins and no cross-reactivity with other antibiotic families. The assay has been designed to detect simultaneously both penicillin species in milk, the antibiotics and their hydrolyzed forms. Concerning the open-ringed forms their detection in food samples will be especially important in the next few years because of the illegal use of penicillinase enzymes by farmers to mask the real concentrations of β-lactams in milk.     

Occurrence of aflatoxin M1 in UHT milk and pasteurized milk in China market

In the present study, the contamination of aflatoxin M1 (AFM1) in 153 UHT milk samples collected in July and September 2010, and 26 pasteurized milk samples collected in September 2010, were assessed using the ELISA method. The AFM1 was detected in 54.9% of UHT milk samples with a concentration of 0.006–0.160 μg/L. Moreover, 96.2% of pasteurized milk samples tested positive for AFM1 with concentration levels of 0.023–0.154 μg/L. The occurrence of AFM1 in all positive samples was far below China's national legal limit of 0.5 μg/L. Meanwhile, the AMF1 content in 20.3% of UHT milk samples and 65.4% of pasteurized milk samples exceeds the European Union's legal limit of 0.05 μg/L.     

Occurrence of four mycotoxins in cereal and oil products in Yangtze Delta region of China and their food safety risks

A total of 76 cereal and oil products collected from Yangtze Delta region of China were analyzed for occurrences of aflatoxins (AFs), aflatoxin B₁ (AFB₁), ochratoxin A (OTA), deoxynivalenol (DON) and zearalenone (ZEN). The mycotoxins were determined by the standard detection procedures using immunoaffinity column clean-up coupled with fluorometer (or HPLC-UV). ZEN was the most prevalent toxin, with the incidence of 27.6% (range = 10.0–440.0 μg kg⁻¹), and 9.2% of the evaluated samples were contaminated with a concentration higher than that of the legislation limit of China (60 μg kg⁻¹). AFs and AFB₁ were detected in 14.5% of the samples analyzed, the concentrations ranging 1.1–35.0 μg kg⁻¹ for AFs, and 1.0–32.2 μg kg⁻¹ for AFB₁; 4.0% of the samples had the concentrations of AFs and AFB₁ higher than that of the corresponding legislation limits of China (5.0, 10.0 and 20.0 μg kg⁻¹ for different products). OTA was detected in 14.5% of the cereal and oil products collected; the concentrations ranged 0.51–16.2 μg kg⁻¹. Only 2 samples showed OTA levels higher than that of the legislation limit of China (5.0 μg kg⁻¹). DON was detected in 7.9% of the samples; the concentrations ranged 100–700 μg kg⁻¹, and none of the samples showed DON concentration higher than that of the legislation limit of China (1.0 mg kg⁻¹). A total of 15.8% cereal and oil products were contaminated with at least two mycotoxins (multiple contaminations with different combinations including AFs-ZEN, AFs-OTA-ZEN, OTA-ZEN, ZEN-DON, OTA-ZEN-DON). The dietary exposure assessment results indicated that AFs (AFB₁), OTA, DON and ZEN from cereal-based products represented a series health risk to both adults and children in Yangtze Delta region of China. This is the first report of safety evaluation associated with major mycotoxins for the area.     

Aflatoxins and ochratoxin A in dried eggplant and green bell pepper

In this study, 50 dried eggplant and 50 dried green bell pepper samples were analyzed in terms of their aflatoxin and ochratoxin A (OTA) content. Aflatoxins G₂, G₁, B₂, and B₁, and OTA contents were analyzed using high-performance liquid chromatography with a flame ionization detector (HPLC–FID). Total aflatoxin and, as well as aflatoxin G₂, G₁, B₂, and B₁ content in dried eggplant samples were ranged between 0.82 and 2.58, 0.10–0.23, 0.32–1.35, 0.12–0.67, and 0.17–0.71 μg kg⁻¹, respectively. Total aflatoxin and, as well as aflatoxin G₂, G₁, B₂ and B₁ content in dried green bell pepper samples were 0.81–2.42, 0.11–0.22, 0.32–1.38, 0.13–0.66, and 0.18–0.91 μg kg⁻¹, respectively. OTA content was varied from 8.88 to 21.35 μg kg⁻¹ in eggplant samples, and from 15.38 to 24.70 μg kg⁻¹ in dried green bell pepper samples. Of the dried eggplant samples and dried green bell pepper samples, 36% and 24% of them, respectively, had aflatoxin B₁ values which were below the minimum limit of detection (LOD) of 0.05 μg kg⁻¹. None of the analyzed samples exceeded the legal limit values of 10 μg kg⁻¹ for total aflatoxin content, and 5 μg kg⁻¹ for aflatoxin B₁ content. However, 80% of the dried eggplant samples and 100% of the dried green bell pepper samples exceeded the legal limit value for OTA content (15 μg kg⁻¹). According to the results, it was concluded that dried vegetables should be examined in terms of their aflatoxins. It is essential to analyze OTA content more thoroughly, as it has the potential to pose a risk for public health, as well as for the economy.     

Application of solid phase extraction and two-dimensional gas chromatography coupled with time-of-flight mass spectrometry for fast analysis of polycyclic aromatic hydrocarbons in vegetable oils

A fast and simple solid-phase extraction (SPE) method followed by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC–TOFMS) has been developed for analysis of 15 + 1 carcinogenic polycyclic aromatic hydrocarbons (PAHs) in vegetable oils. Of three critically assessed sample preparation approaches – (i) gel permeation chromatography (GPC), (ii) GPC followed by silica based SPE, and (iii) SPE employing PAHs-dedicated molecularly imprinted polymers (MIPs), the latter one was selected as the best option. Recoveries of the overall analytical procedure ranged from 70 to 99%, with repeatabilities in the range of 2–11%. Limits of quantitation (LOQs) ranging for individual PAHs from 0.1 to 0.3 μg kg⁻¹, were fairly below the maximum level 2 μg kg⁻¹ established for the PAHs representative, benzo[a]pyrene (BaP), by EU Legislation for this commodity. Within the mini-survey in which the new method was employed for examination of 35 samples of various kinds of vegetable oils collected at the Czech market, the highest PAH4 levels, i.e. the sum of BaP, benz[a]anthracene (BaA), benzo[b]fluoranthene (BbFA) and chrysene (CHR) were found in sea buckthorn (708 μg kg⁻¹) followed by rapeseed oil (99.8 μg kg⁻¹). Altogether 8 samples from 35 examined vegetable oils exceeded the maximum limit 2 μg kg⁻¹ for BaP and 10 samples exceeded 10 μg kg⁻¹ set for PAH4 which is fixed by Commission Regulation (EU) no 835/2011 for oils.     

Mycotoxin contamination in corn smut (Ustilago maydis) galls in the field and in the commercial food products

Corn infected with Ustilago maydis, causal agent of common smut disease, produces galls that are used as food in certain cultures, but may be contaminated with mycotoxins. The objective of this study was to determine mycotoxin levels in common smut galls (CSGs) collected from the field at corn ear reproductive stages R1 through R5 and in commercial CSGs products. The study was conducted in 2012 and 2013. A simple extraction method for five mycotoxins was devised and the results showed the presence of these compounds in CSGs in corn during ear development at various physiological stages. Fumonisin was the major mycotoxin in CSG samples in both 2012 (63%, ≤150.7 μg g⁻¹) and 2013 (46.9%, ≤20.9 μg g⁻¹); followed by aflatoxin (2012: 2%, ≤14.7 ng g⁻¹; 2013: 30.6%, ≤10.8 ng g⁻¹) and zearalenone (2012: ≤41.70 ng g⁻¹; 2013: ≤12.40 ng g⁻¹). Deoxynivalenol (DON) was only detected in 2012 (≤1.6 μg g⁻¹), and cyclopiazonic acid was only detected in 2013 (≤3.18 μg g⁻¹). Commercial canned and fresh CSG samples also contained detectable amounts of mycotoxins including aflatoxin, fumonisin, CPA, and DON. Aspergillus flavus was isolated from selected 2013 CSG field samples at R2 or older (0–1.6 × 10⁶ cfu/g), whereas Fusarium spp were isolated at R1 or older (0–7.5 × 10⁷ cfu/g). These results indicate that CSGs can be infected with mycotoxigenic fungi and contaminated with mycotoxins. The incidence of mycotoxins in commercially available CSG products was highly variable and warrants further study.     

Estimated daily intake of organochlorine pesticides from dairy products in Brazil

The estimated daily intake (EDI) of organochlorine (OC) pesticides (HCB, α-HCH, lindane, aldrin, p,p′-DDE, p,p′-DDD, and o,p′-DDT) through consumption of dairy products from Rio Grande do Sul State (Brazil) was investigated. Fluid milk and cheese had similar ΣOC levels (26.04 and 26.14 ng g⁻¹ fat, respectively), whereas milk powder had lower levels (2.23 ng g⁻¹ fat). OC levels in UHT milk exhibited a declining trend over time (ΣOC = 27.70 ng g⁻¹ fat in 2000 vs. 1.50 ng g⁻¹ fat in 2009/2010). The EDI of OC pesticides was remarkably higher for children (8.266 ng kg⁻¹ day⁻¹) than for adolescents, adults, and the elderly (ranging from 0.393 ng kg⁻¹ day⁻¹ to 0.614 ng kg⁻¹ day⁻¹). The average EDIs for OC pesticides were below the acceptable daily intakes (ADI), with the exception of aldrin, which greatly exceeded the ADI for children. In addition, some samples (8.8%) exceeded the maximum residue limit for the compounds evaluated.     

Determination of aflatoxins in walnut sujuk and Turkish delight by HPLC-FLD method

This study aims to assess the risk of aflatoxins (AFs) in traditional confectionery products (walnut sujuk and Turkish delight) of Turkey. A high performance liquid chromatography coupled with fluorescence detection (HPLC-FLD) method was used for the determination of AFs. Evaluation of the method showed good selectivity, linearity, recovery and precision. The limit of quantification (LOQ) ranged from 0.106 to 0.374 μg kg⁻¹. The expanded measurement uncertainty was less than 40% for all target analytes. The validated method was successfully applied to the determination of AFs in 112 traditional confectionery products containing nuts (hazelnuts and walnuts). AFs were detected in 43.8% of walnuts and 60.9% of hazelnuts used as ingredients in walnut sujuk and Turkish delight and at levels ranging from 0.58 to 15.2 μg kg⁻¹ and 0.43–63.4 μg kg⁻¹, respectively. This means that AFs levels in walnut sujuk and Turkish delight were up to levels of 6.1 and 9.5 μg kg⁻¹, respectively. Six walnut samples and twenty-one hazelnut samples were above the EU maximum limits (MLs) of 2 and 5 μg kg⁻¹ for aflatoxin B₁ (AFB₁), respectively.     

Multi-class determination of pesticides and mycotoxins in isoflavones supplements obtained from soy by liquid chromatography coupled to Orbitrap high resolution mass spectrometry

A methodology has been developed to identify and quantify 257 toxic substances (including pesticides and mycotoxins) in diverse isoflavones supplements obtained from soy. Two different extraction procedures were compared, QuEChERS and “dilute and shoot”. The best results were observed when the “dilute and shoot” methodology was applied using acetonitrile acidified with formic acid (1% v/v) as extraction solvent followed by a clean-up step with Florisil cartridges. Validation of the method was carried out evaluating trueness, repeatability and intermediate precision, obtaining recoveries between 70 and 120% with relative standard deviation (RSD) values lower than 20%. Limits of detection and quantification were below 5 and 10 μg kg⁻¹ respectively. The validated methodology was applied to the analysis of real samples, finding pesticides such as flutolanil (12.2 μg kg⁻¹) and etofenprox (48.2 μg kg⁻¹). Regarding mycotoxins, aflatoxin B1 (8.2–17.1 μg kg⁻¹) and aflatoxin G2 (6.4 μg kg⁻¹) were detected.