An immunomagnetic-bead-based enzyme-linked immunosorbent assay for sensitive quantification of fumonisin B1

A sensitive enzyme-linked immunosorbent assay (ELISA) based on immunomagnetic beads (IMB-ELISA) was established using a magnetic-bead signal-enrichment system. The immunomagnetic beads were coated with polyclonal antibody directed against keyhole limpet hemocyanin (KLH), which were then coupled with a KLH–fumonisin B1 (FB1) conjugate. Anti-FB1 monoclonal antibody and sample extract were mixed and added to the immunomagnetic-bead solution. After the addition of horseradish peroxidase (HRP)-labeled goat anti-mouse antibody and the substrate solution, stop solution was added and the optical density of the reaction mixture was determined. To improve the performance of this method, the dilution of the immunomagnetic beads, the concentrations of the monoclonal antibody and HRP-labeled goat anti-mouse antibody, and the incubation time for the competition reaction were optimized. Based on the optimum conditions, the regression equation for this IMB-ELISA in quantifying FB1 was y = −0.3538x + 0.703 (R² = 0.9988). The detection limit and IC₅₀ were 0.24 ng/mL and 3.17 ng/mL, respectively. The working range was 0.54–26.3 ng/mL. The recovery rates were 80.4–114.7%, when the spiked concentrations ranged from 19.5 to 156.3 μg/kg. This IMB-ELISA is accurate and more sensitive and less time-consuming than the conventional ELISA.     

Determination of difenoconazole residue in tomato during home canning by UPLC-MS/MS

The effects of different steps in canned tomato paste production on difenoconazole levels were investigated. And residues were determined by using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) after each stage including washing, peeling, homogenization, simmering and sterilization. Results showed that washing and peeling process reduced the amount of residue by 99%, whereas homogenization, simmering, and sterilization process had little effects on the removal of difenoconazole residue. Difenoconazole mostly remained in tomato skin, therefore, washing and peeling significantly reduced difenoconazole, especially peeling resulted in nearly 94.6% difenoconazole removal from tomatoes, with the processing factor of peeling at < 0.05.     

GC/MS法测定工业污水中有机物

采用液-液萃取法对炼油废水中有机物样品进行处理，对分离条件做了探讨。用GC／MS法进行测定并定性分析。     

Contamination of UHT milk by aflatoxin M1 in Iran

In this study the levels of aflatoxin M₁ (AFM₁) in UHT milk samples were determined in May, August and November and February. Two hundred and ten UHT milk samples were obtained from supermarkets in Tehran, Iran. The occurrence and concentration range of AFM₁ in the samples were investigated by competitive enzyme-linked immunoabsorbent assay (ELISA) method. AFM₁ was found in 116 (55.2%) of 210 UHT milk samples examined. The levels of AFM₁ in 70 (33.3%) samples were higher than the maximum tolerance limit (0.05 μg/l) accepted by some European countries while none of the samples exceeded the prescribed limit of US regulations. The highest mean concentration of AFM₁ was recorded in February (0.087 μg/l). The lowest mean concentration of AFM₁ was recorded in August (0.021 μg/l). Statistical evaluation showed that there were significant difference (P < 0.01) between the mean concentrations of AFM₁ of UHT milk samples taken in February with May and August. AFM₁ contents of milk samples taken in February were not higher than UHT milk samples taken in November (P < 0.01). The AFM₁ incidence of exceeding legal limit in UHT milk samples (33.3%) was relatively much higher than some other countries. It was therefore concluded that, the levels of AFM₁ in UHT milk samples consumed in Iran were high and seemed to pose a threat to public health.     

Assessment of aflatoxin M1 contamination in the milk of four dairy species in Croatia

Aflatoxin M1 (AFM1) concentrations were measured in bulk cow milk samples from eastern Croatia, and in cow, goat, sheep and donkey bulk milk samples from other parts of Croatia during the period July–September 2013. AFM1 levels in milk were measured in the ranges (ng/L): cow 3.65–162.3 (eastern Croatia) and 2.69–44.9 (other regions of Croatia); goat 2.78–40.8; sheep 2.11–5.87; donkey 3.43–10.4. The concentration of AM1 exceeded the EU MRL in 6.7% of cow milk samples from eastern Croatia. The highest level measured was 162.3 ng/L. AFM1 levels exceeded the LOQ value (23.2 ng/L) in only 59 samples of cow milk and two samples of goat milk of the total 402 samples analysed. A significant difference was found between the mean AFM1 concentrations of cow milk from eastern and other regions of Croatia (P < 0.05). The elevated AFM1 levels in cow milk from eastern Croatia indicate the use of contaminated supplementary feedstuff in some farms during the study period.     

Molecular Characterization of Hydrotreated Atmospheric Residue Derived from Arabian Heavy Crude by GC FI/FD TOF MS and APPI FT-ICR MS

High resolution mass spectrometry in combination with distillation and SARA fractionation provides us an opportunity for in-depth understanding about the hydrotreating process at the molecular level. In this study, the atmospheric residue derived from Arabian heavy crude and its hydrotreated products were initially subjected to distillation and SARA fractionation. The saturates were characterized by GC FI/FD TOF MS. The aromatics and resins were characterized by APPI FT-ICR MS. Compositional changes of different compounds (paraffins, naphthenes, aromatic hydrocarbons, and heteroatomic compounds) contained in different distillates (vacuum gas oil, vacuum residue) were obtained. More detailed knowledge about the hydrotreating process was achieved.     

Incidence of aflatoxin M1 in human breast milk in Tehran, Iran

This study examined the exposure of infants to aflatoxin M1 (AFM1) and of lactating mothers to aflatoxin B1 (AFB1), using AFM1 in breast milk as a biomarker for exposure to AFB1. An enzyme-linked immunosorbent assay (ELISA) was modified for the analysis of AFM1 in breast milk samples from 160 women in Tehran, Iran. AFM1 was detected in 157 samples by average concentration of 8.2 ± 5.1 ng/kg (range 0.3–26.7 ng/kg).The concentration of AFM1 in one sample was higher than the maximum tolerance limit accepted by European Union and USA (25 ng/kg), but in 55 samples was higher than the maximum concentration recommended by Australia and Switzerland (10 ng/kg).Logistic regression Analysis failed to show significant correlation between AFM1 and gestational age, education, postnatal age, gender, nationality, clinical condition, the number of family member, the number of children, type and amount of dairy consumption, vegetable, fruits, oil and meat. But it was significant relation to the cereal consumption, also to the height at birth.     

GC/MS分析油酸乙二醇单酯的组成

用硅胶玻璃色谱柱吸附样品,采用溶剂梯度洗脱的方法从油酸乙二醇酯添加剂中分离出油酸乙二醇单酯,再用ＧＣ／ＭＳ详细地分析了油酸乙二醇单酯的组成和结构,并通过油酸乙二醇单酯的结构推断出油酸原料中所含酸的种类,从ＧＣ／ＭＳ分析领域给出了分析油酸乙二醇单酯的较好方法     

Levels of aflatoxin M1 in different types of milk collected in Serbia: Assessment of human and animal exposure

The level of aflatoxin M1 (AFM1) in 50 milk samples collected from February to June 2013 from Serbian market or domestically produced was determined using simple non-specific sample preparation method based on solid phase extraction (Oasis HLB, Waters) and ultra-high performance liquid chromatography with heated electrospray ionization triple quadrupole mass spectrometry (UHPLC/HESI-MS/MS). The range of detection was between < LOD and 1.44 μg/kg with mean value of 0.30 μg/kg. Thirty-eight samples (76%) exceed the maximum level of 0.05 μg/kg sets by EU. The highest level of 1.44 μg/kg was found in raw sample of domestically produced milk while the lowest one in organic produced milk. The evaluation of the exposure degree of AFM1 through the milk consumption by the average Serbian citizen was estimated at levels of 1.420, 0.769 and 0.503 ng/kg bw/day during February, April and May, respectively. Estimation of the corresponding concentration of AFB1 in feedstuffs was evaluated as 18.75 μg/kg. The calculated hazard index of 7.1, 3.8 and 2.5 for February, April and May, respectively, was higher than 1 indicated serious risk of AFM1 to Serbian consumers. This work presents the first insight in the occurrence of AFM1 in milk collected in Serbia as well as mycotoxin intake through milk consumption by Serbian adult population.     

A survey of aflatoxin M1 of raw cow milk in China during the four seasons from 2013 to 2015

In the present study, a total of 1550 raw cow milk samples were collected from Southern, Northern, Northeast, and Western regions of China during the four seasons from 2013 to 2015. Samples were analyzed for aflatoxin M1 (AFM1) using high performance liquid chromatography (HPLC). In 2013, AFM1 was detected in 21% of 366 raw cow milk samples with levels ranging between 0.01 and 0.24 μg/L. In 11.7% of samples, AFM1 levels were >0.05 μg/L, which is the legal limit in the European Union. The mean and median of positive samples were 0.069 ± 0.052 μg/L and 0.056 μg/L, respectively. In 2014, AFM1 was detected in 28.5% of 624 raw cow milk samples, with levels ranging from 0.01 to 0.25 μg/L. Of these samples, 7.7% had AFM1 levels exceeding 0.05 μg/L, with a mean of 0.042 ± 0.039 μg/L and median of 0.028 μg/L. AFMI was detected in 14.1% of 560 raw cow milk samples in 2015, with levels ranging from 0.01 to 0.144 μg/L. In 1.8% of these samples, AFM1 levels were above 0.05 μg/L, with a mean of 0.026 ± 0.024 μg/L and median of 0.017 μg/L. Our results demonstrate that AFM1 levels of the samples did not exceed the legal limit of 0.5 μg/L in China, the United States, and Codex Alimentarius Commission. Geographically, AFM1 contamination was more predominant in raw cow milk samples from Southern China than in those from other regions, with a higher number of samples containing AFM1 levels above 0.05 μg/L in 2013, 2014, and 2015. AFM1 levels were higher in autumn than in the other seasons during the entire study period. According to our survey, AFM1 contamination has been well-controlled in China during recent years; however, some samples still exceeded the European Union (EU) legal limit. Better prevention and management of aflatoxins in both feed and milk should be considered especially in Southern regions of China and in autumn.     

Monitoring the presence of residues of tetracyclines in baby food samples by HPLC-MS/MS

Tetracyclin is a group of antimicrobial permitted in animal food production, but their concentrations in food of animal origin should not exceed 100 μg kg⁻¹ (in meat and milk). Although the detection of these substances above these limits involves fines and jail for the producer, residues of tetracyclines are still being detected in food a potential risk to consumer health, especially babies.In the past, baby foods were carefully prepared at homes. However, modern lifestyles have led to the commercialization of ready-made baby food. Generally, these products are made with vegetable and meat from different animals, such as pork, chicken or beef. The presence of tetracyclines in meat at concentrations above 100 μg kg⁻¹ is forbidden in Europe by the Regulation 37/2010. Consequently this concentration is also applicable to the portion of meat present in baby food. Even if the presence of tetracyclines is controlled regularly in meat, they should also be monitored in baby food as babies are vulnerable to such as drugs.A rapid analytical method based on high-performance liquid chromatography coupled to a tandem mass spectrometer (HPLC-MS/MS) for quantification of four tetracyclines (tetracycline, chlortetracycline, doxycycline and oxytetracycline) in baby food is presented. The tetracyclines are extracted with EDTA-McIlvaine buffer, acidified at pH 4.0, followed by liquid–liquid extraction with ethyl acetate. The final extract is analysed within 19 min on a Sunfire HPLC column from Waters. Validation was performed according to the Commission Decision 2002/657/EC. The mean accuracy was 103 μg kg⁻¹, and the mean precision, was less than 23% for all the tetracyclines. The method was tested on 31 prepared baby food samples containing vegetable and beef. The presence of oxytetracycline was detected in one of the samples at a concentration of 5 μg kg⁻¹.     

Two year survey on the occurrence and seasonal variation of aflatoxin M1 in milk and milk products in Serbia

The incidence of contamination of aflatoxin M1 (AFM1) in milk and milk products samples collected in Serbia was investigated by using the competitive enzyme linked immunosorbent assay (ELISA) technique. A total of 1438 samples composed of 678 raw milk, 438 heat treated milk and 322 milk product samples that were analyzed during the period of 2013–2014, including all seasons. The AFM1 levels exceeded the European Union maximum residue permitted amount (EU MRL) in 56.3% raw milk, 32.6% heat treated milk and 37.8% of milk product samples. Milk powders had the highest mean AFM1 concentration (0.847 μg/kg) of all types of milk products examined. Mean concentration of AFM1 in raw milk samples during the period of winter in Serbia was 0.358 μg/kg and did not significantly differ from the mean concentrations of 0.375 μg/kg during the spring. However, the AFM1 raw milk concentration in the summer (0.039 μg/kg) and autumn season (0.103 μg/kg) was significantly lower. Seasonal variation of AFM1 concentrations in heat treated milk samples followed the trend observed in raw milk. Mean raw milk AFM1 concentration has dropped down by 10 fold from 0.314 μg/kg in 2013 to 0.035 μg/kg in 2014. The fraction of raw milk samples exceeding the EU MRL has decreased from 62.3% to 11.5% by the end of 2014.     

Analytical Profile of Organo-nitrogen Compounds in Gulf Coast Refined Fuels by GC/MS

This study examines the composition of two samples of crude fuels originating from the Gulf Coastal areas of the United States. Both nitrogen-containing basic compounds as well as non-basic hydrocarbon compounds were evaluated for presence and relative amount in these two samples. The extractions of the basic nitrogenous compounds were achieved with weak acid extractions. The basic nitrogenous compounds, due to emulsification, formed two distinct fractions. The nitrogenous based-compounds were comprised of pyridines, quinolines, tetrahydroquinolines, indoles, and carbazoles to varying amounts. The hydrocarbon content in each of the two fuels analyzed was found to contain mostly naphthols.     

Analytical Profile of Organo-nitrogen Compounds in Gulf Coast Refined Fuels by GC/MS

Abstract

This study examines the composition of two samples of crude fuels originating from the Gulf Coastal areas of the United States. Both nitrogen-containing basic compounds as well as non-basic hydrocarbon compounds were evaluated for presence and relative amount in these two samples. The extractions of the basic nitrogenous compounds were achieved with weak acid extractions. The basic nitrogenous compounds, due to emulsification, formed two distinct fractions. The nitrogenous based-compounds were comprised of pyridines, quinolines, tetrahydroquinolines, indoles, and carbazoles to varying amounts. The hydrocarbon content in each of the two fuels analyzed was found to contain mostly naphthols.     

Evaluation of fumonisin exposure by determination of fumonisin B1 in human hair and in Brazilian corn products

The aim of this study was to evaluate the dietary exposure to fumonisin B₁ (FB₁) through determination of residual FB₁ in hair and corn products consumed by 56 volunteers from Pirassununga and Erval Velho, Brazil. Data from FB₁ analyses in corn products and a Food Frequency Questionnaire (FFQ) were used for estimating the mean probable daily intake (PDI_M) for FB₁. FB₁ was detected in 4 human hair samples (7.2%), at a mean level of 21.3 ± 12.1 ng g⁻¹. The mean FB₁ level found in corn products was 360.4 ± 555.1 μg kg⁻¹. The PDI_M value of FB₁ in volunteers was 159 ± 47 ng kg⁻¹ body weight day⁻¹ which represents 7.9% of the provisional maximum tolerable daily intake (PMTDI) recommended for fumonisins. The FB₁ levels found in human hair samples from each volunteer were associated with their individual PDI of FB₁, indicating that exposure to FB₁ in the sample studied do not represent a health concern. This is the first report on the incidence of FB₁ in individual human hair in Brazil.     

Characterization of n-alkanes and n-alkylbenzenes from different sediments by Py-GC/MS

Sediments from a selection of source were systematically pyrolysed in two kinds of experiments (single stage and multi-stage) using analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) in order to investigate the n-alkanes and n-alkylbenzenes obtained in pyrolysate volatiles. Our results show that the n-alkanes can be detected by Py-GC/MS, this may be related to the high molecular cleavage of the diverse organic matter constituents under the thermal conditions. And n-alkylbenzenes were also detected, probably produced in connection with n-alkanes, or products of their subsequent evolution. In addition, both sets of experimental results suggested that organic matter adsorbed in modern sediments differs from that in source rocks where organic matter is bound in kerogen, thus the primary stage of products in modern sediments is earlier than that in source rocks.     

Determination of nutritional and toxic elements in pasteurized bovine milk from Vale do Paraiba region (Brazil)

Throughout the year of 2004, 54 samples (1 L each) were collected from commercial sources in the Vale do Paraíba region (eastern portion of São Paulo State, Brazil). The concentrations of (Ca, Cr, Cu, Fe, Mg, Mn, Ni, Se, Zn, Cd and Pb) in these samples were analyzed by two atomic-absorption spectroscopy (AAS) methods. Ca, Cu, Fe, Mg and Zn were determined by flame atomic-absorption spectroscopy (FAAS) and (Cd, Cr, Mn, Ni, Pb and Se) were determined by electrothermal atomic-absorption spectroscopy (ETAAS). Tests to determine and quantify essential, nonessential and toxic elements present in bovine milk are rare in Brazil, especially so for Vale do Paraiba region. Tests were performed on standard NIST-certified milk-powder to validate the reliability of subsequently collected analytical data. Ca presented a lower recovery value (85.3%). The finding for Ca macro-nutrient was found to be below recommended international standards (1300 mg/L) for all samples possibly due to milk heterogeneity and losses in the pasteurization process. Significant results for Pb were found in all milk samples with average values at 0.230 mg/L from a minimum of 0.062 mg/L and maximum of 0.476 mg/L.     

芳烃生产新工艺中原料和产物的GC／MS分析

利用ＧＣ／ＭＳ联用法对芳烃生产新工艺中的原料和产物进行了分析，其中原料定出２６个组份，产物定出２４个组份，并用面积归一化法对原料和产物中的各个组份的含量进行了定量计算，为芳烃生产新工艺中的新型芳构化催化剂ＡＦ－５的推广运用提供了科学依据。     

Study on the fast pyrolysis of oil sludge by PY-GC/MS

Oil sludge is an organic solid waste produced in oilfield exploitation, transportation, and petroleum refineries. Pyrolysis is one of the most effective ways to reduce oil sludge and realize energy re-utilization. In the present work, the amounts and distributions of pyrolysis products at different reaction time and with different amounts of NiO catalyst were investigated with PY-GC/MS. The results suggest that the degree of the pyrolysis reaction increased and more macromolecules were degraded into smaller hydrocarbons as the reaction time prolonged. The addition of NiO catalyst effectively promoted the conversion of aromatic and paraffin products, and increased the production of small molecule olefins.     

Inhibition of aflatoxin B1, B2, G1 and G2 production by Aspergillus parasiticus in nuts using yellow and oriental mustard flours

Aflatoxins (AFs) are naturally occurring mycotoxin compounds produced by several species of Aspergillus, as Aspergillus flavus and Aspergillus parasiticus and are mutagenic, teratogenic, and carcinogenic compounds that have been implicated as causative agents in human hepatic and extra hepatic carcinogenesis. In this study, the reduction of the AFs present in dried fruits (peanut, cashew, walnut, almond, hazelnut and pistachio), produced by A. parasiticus CECT 2681, by isothiocyanates (ITCs) generated by the enzymatic hydrolysis of the glucosinolates (GLCs) present in oriental and yellow mustard flours was evaluated. The AFs reduction activity through ITCs application in dried fruits was carried out using a model and food system experiments. The quantification of the AFs in the food products analyzed was carried out employing the technique of the liquid chromatography (LC) coupled to the mass spectrometry detection in tandem (MS/MS). The ITCs produced through GLCs hydrolysis reduced the A. parasiticus growth in the food products tested and in particular in the model system experiments the AFs B₁, B₂, G₁ and G₂ reduction ranged meanly from 83.1 to 87.2% using the oriental mustard flour, whereas employing the yellow flour the mean reduction observed ranged from 27.0 to 32.5%. In the food system experiments carried out employing only the oriental mustard flour the mean AFs reduction observed ranged from 88 to 89%.