Exogenous Contamination Research Articles

Pyrolysis comprehensive gas chromatography and mass spectrometry: A new tool to assess the purity of ancient collagen prior to radiocarbon dating

Exogenous carbonaceous contaminants coming from sediments significantly bias the radiocarbon date of collagen samples extracted from archaeological bone and teeth. In this study, a new approach combining pyrolysis, comprehensive gas chromatography and mass spectrometry (Py-GC × GC/MS) was proposed to ensure their removal during the demineralization and bone collagen extraction. This approach permitted to identify hydrocarbon contaminants for archaeological samples from the Neolithic period, in 30–40 μg of collagen. The use of 2D GC improved importantly the separation, selectivity and resolution compared to 1D GC thus permitting to detect organic contaminants within the complex chromatograms issued from collagen pyrolysis. Moreover, efficiency of the extraction steps in collagen sample preparation for radiocarbon dating (acid and alkali treatments, filtration steps) could be evaluated for four different protocols on the basis of organic contaminant removal. Radiocarbon dating of the extracted collagen of four of the tested protocols corroborated the results of the Py GC × GC/MS data. This approach opens new perspectives for the use of comprehensive gas chromatography in the domain of archaeological sciences.

HBCD and TBBPA in human scalp hair: Evidence of internal exposure

Human biomonitoring is a reliable method for evaluating human exposure to specific contaminants. Although blood is an ideal matrix for monitoring purposes, it is regarded as an invasive matrix. Therefore, current developments in the field of human biomonitoring are based on introducing new methods that use non-invasive matrices, such as hair. In this study, we examined the efficiencies of several extraction methods for the analysis of hexabromocyclododecane (HBCD) and tetrabromobisphenol-A (TBBPA) in human hair. The selected pretreatment method was validated through a general QA/QC process that included spiking experiments, and then, the method was used for the determination of HBCD and TBBPA concentrations in scalp hair samples collected from individuals in Korea (n = 24) and Iran (n = 15). The HBCD and TBBPA concentrations in the collected hair samples ranged from ND to 3.24 ng g−1 and ND to 16.04 ng g−1, respectively. Significantly higher concentrations of TBBPA were found in hair samples from Korea than those in hair samples from Iran (p < 0.05), which is expected to be the result of the large market and higher exposure of TBBPA in Korea. HBCD was not detected in hair samples from Iran. According to our knowledge this is the first study demonstrating the presence of TBBPA in human hair with nonspecific exposure. Lastly, we investigated the important factors that influence the interpretation of the contributions of endogenous and exogenous contaminations in hair. Based on the information, the HBCD and TBBPA in the collected hair samples were most likely from endogenous exposure. Therefore, our study showed that hair is potentially a suitable indicator for the monitoring of internal exposure to HBCD and TBBPA in different populations.

Polygonum multiflorum Thunb.: A Review on Chemical Analysis, Processing Mechanism, Quality Evaluation, and Hepatotoxicity.

Polygonum multiflorum Thunb. and its processed products have been used in China for centuries due to their multiple beneficial effects to human body. Currently, liver injuries caused by taking P. multiflorum have been reported worldwide, but the potential toxic components and possible mechanism that caused hepatotoxicity remain unclear. It is worth noting that the processing procedure could significantly decrease the toxicity of raw P. multiflorum and the processed products of P. multiflorum are considered to be relatively safe. However, the processing mechanism is still ambiguous, and there is the lack of a scientific approach to control the quality of P. multiflorum praeparata. This study is the first review that summarizes the recently advances (from 2007 to 2017) in the chemical analysis of P. multiflorum, and provides comprehensive information on the quantitative and qualitative analysis of P. multiflorum as well as its related species. In addition, the processing mechanism and quality evaluation of processed P. multiflorum are discussed. Moreover, the toxicity of P. multiflorum is analyzed from the perspectives of exploration of the proposed toxic ingredients, metabolite identification, metabolomics studies, and exogenous contaminant determination. Furthermore, trends and perspectives for future research of this medicine are discussed.

Determinants of Hair Manganese, Lead, Cadmium and Arsenic Levels in Environmentally Exposed Children.

Biomarkers of environmental metal exposure in children are important for elucidating exposure and health risk. While exposure biomarkers for As, Cd, and Pb are relatively well defined, there are not yet well-validated biomarkers of Mn exposure. Here, we measured hair Mn, Pb, Cd, and As levels in children from the Mid-Ohio Valley to determine within and between-subject predictors of hair metal levels. Occipital scalp hair was collected in 2009–2010 from 222 children aged 6–12 years (169 female, 53 male) participating in a study of chemical exposure and neurodevelopment in an industrial region of the Mid-Ohio Valley. Hair samples from females were divided into three two centimeter segments, while males provided a single segment. Hair was cleaned and processed in a trace metal clean laboratory, and analyzed for As, Cd, Mn, and Pb by magnetic sector inductively coupled plasma mass spectrometry. Hair Mn and Pb levels were comparable (median 0.11 and 0.15 µg/g, respectively) and were ~10-fold higher than hair Cd and As levels (0.007 and 0.018 µg/g, respectively). Hair metal levels were higher in males compared to females, and varied by ~100–1000-fold between all subjects, and substantially less (<40–70%) between segments within female subjects. Hair Mn, Pb, and Cd, but not As levels systematically increased by ~40–70% from the proximal to distal hair segments of females. There was a significant effect of season of hair sample collection on hair Mn, Pb, and Cd, but not As levels. Finally, hair metal levels reported here are ~2 to >10-fold lower than levels reported in other studies in children, most likely because of more rigorous hair cleaning methodology used in the present study, leading to lower levels of unresolved exogenous metal contamination of hair.

Proteomic characterization of human exhaled breath condensate

To improve biomedical knowledge and to support biomarker discovery studies, it is essential to establish comprehensive proteome maps for human tissues and biofluids, and to make them publicly accessible. In this study, we performed an in-depth proteomics characterization of exhaled breath condensate (EBC), a sample obtained non-invasively by condensation of exhaled air that contains submicron droplets of airway lining fluid. Two pooled samples of EBC, each obtained from 10 healthy donors, were processed using a straightforward protocol based on sample lyophilization, in-gel digestion and liquid chromatography tandem-mass spectrometry analysis. Two ‘technical’ control samples were processed in parallel to the pooled samples to correct for exogenous protein contamination. A total of 229 unique proteins were identified in EBC among which 153 proteins were detected in both EBC pooled samples. A detailed bioinformatics analysis of these 153 proteins showed that most of the proteins identified corresponded to proteins secreted in the respiratory tract (lung, bronchi). Eight proteins were salivary proteins. Our dataset is described and has been made accessible through the ProteomeXchange database (dataset identifier: PXD007591) and is expected to be useful for future MS-based biomarker studies using EBC as the diagnostic specimen.

Forensic analysis of diatom in the spleen and heart in Sprague-Dawley rats

Post-mortem diagnosis of drowning is a real challenge, especially in a decomposed body. The diatom test is considered a reliable scientific assessment in several countries including China. The lungs, liver, and kidneys are usually used in the diatom test, whereas the spleen and heart are rarely reported. In our study, we set up five water samples with different concentrations of diatoms. One-hundred and twenty adult SD rats were employed, assigned to the Drowning Group (DG), Post-mortem Submersion Group (PSG), Drowning Control Group (DG-Control), and Post-mortem Submersion Control Group (PSG-Control). Rats in DG and PSG were submerged in water samples, respectively. After the microwave digestion and vacuum filtration method for diatom enrichment, the diatom numbers were counted. The results showed no diatom was found in either the DG-Control or PSG-Control group. Although significant differences in the diatoms number were found between the DG and PSG groups, the heart and spleen revealed no significant differences. These two organs equally had high specificity and low sensitivity. Based on our data, we concluded that the heart and spleen can be used for the diagnosis of drowning, and detection of diatoms in systemic circulation organs may be more suitable for the diatom test, especially when exogenous contamination is avoided.

Assessment of Capacity to Capture DNA Aerosols by Clean Filters for Molecular Biology Experiments.

Experimental contamination by exogenous DNA is a major issue in molecular biological studies for data quality and its management. We herein assessed DNA aerosols for the risk of contamination and tested the capacity of clean air filters to trap and remove DNA aerosols. DNA aerosols were generated by atomizing a DNA solution and introduced into a laminar flow clean air unit. Capture and detection performed upstream and downstream of the clean air unit showed that a significant fraction (>99.96%) of introduced molecules was trapped and removed by the filter. Although DNA aerosols appear to be an avoidable source of exogenous contamination, a clearer understanding and careful experimental procedures are needed in order to perform contamination-free, high-quality molecular biology experiments.

Characterization of Proteomes Extracted through Collagen-based Stable Isotope and Radiocarbon Dating Methods.

Isotope analyses on "collagen" extracted from ancient bone have been routinely used for dietary and chronological inferences worldwide for decades. These methods involve the decalcification of biomineralized tissues with acid, often followed by processes to remove exogenous contaminants, and then gelatinization of what is often described as the "collagen" fraction. However, little is known about the relative content of collagen to the many other noncollagenous proteins (NCPs) potentially present. Some of these NCPs have great longevity in ancient bone, and some, for example, fetuin-A, are useful for obtaining better taxonomic information than collagen. This study uses Orbitrap Elite LC-MS/MS to characterize the proteomes of the acid-soluble and base-soluble fractions, which are usually discarded, and the gelatinized "collagen" fraction obtained from both stable isotope and radiocarbon methods applied to several ancient bovine bones. The results showed that all fractions tested contain numerous NCPs, but the base-soluble fraction for both methods contains the greatest number of NCPs with the highest relative abundances. This study confirms that not only do the waste fractions obtained from the "collagen" extraction procedure of stable isotope or radiocarbon dating methods yield a plentiful resource of NCPs that is currently being overlooked but that they also provide proteomes as complex as those obtained from standard proteomics methods.

Characterization of bacterial diversity in contaminated groundwater using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Groundwater is a major source for drinking water in the United States, and therefore, its quality and quantity is of extreme importance. One major concern that has emerged is the possible contamination of groundwater due to the unconventional oil and gas extraction activities. As such, the impacts of exogenous contaminants on microbial ecology is an area to be explored to understand what are the chemical and physical conditions that allow the proliferation of pathogenic bacteria and to find alternatives for water treatment by identifying organic-degrading bacteria. In this work, we assess the interplay between groundwater quality and the microbiome in contaminated groundwaters rich in hydrocarbon gases, volatile organic and inorganic compounds, and various metals. Opportunistic pathogenic bacteria, such as Aeromonas hydrophila, Bacillus cereus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia, were identified, increasing the risk for consumption of and exposure to these contaminated groundwaters. Additionally, antimicrobial tests revealed that many of the identified bacteria were resistant to different antibiotics. The MALDI-TOF MS results were successfully confirmed with 16S rRNA gene sequencing, proving the accuracy of this high-throughput method. Collectively, these data provide a seminal understanding of the microbial populations in contaminated groundwater overlying anthropogenic activities like unconventional oil and gas development.

A Comprehensive Quality Evaluation System for Complex Herbal Medicine Using PacBio Sequencing, PCR-Denaturing Gradient Gel Electrophoresis, and Several Chemical Approaches.

Herbal medicine is a major component of complementary and alternative medicine, contributing significantly to the health of many people and communities. Quality control of herbal medicine is crucial to ensure that it is safe and sound for use. Here, we investigated a comprehensive quality evaluation system for a classic herbal medicine, Danggui Buxue Formula, by applying genetic-based and analytical chemistry approaches to authenticate and evaluate the quality of its samples. For authenticity, we successfully applied two novel technologies, third-generation sequencing and PCR-DGGE (denaturing gradient gel electrophoresis), to analyze the ingredient composition of the tested samples. For quality evaluation, we used high performance liquid chromatography assays to determine the content of chemical markers to help estimate the dosage relationship between its two raw materials, plant roots of Huangqi and Danggui. A series of surveys were then conducted against several exogenous contaminations, aiming to further access the efficacy and safety of the samples. In conclusion, the quality evaluation system demonstrated here can potentially address the authenticity, quality, and safety of herbal medicines, thus providing novel insight for enhancing their overall quality control.Highlight: We established a comprehensive quality evaluation system for herbal medicine, by combining two genetic-based approaches third-generation sequencing and DGGE (denaturing gradient gel electrophoresis) with analytical chemistry approaches to achieve the authentication and quality connotation of the samples.

Effects of selected industrial pollutants on urban WWTPs activated sludge population, and possible mitigation strategies

This study concerns the effects on microbial populations and treatment plant performance on the presence of Chromium and surfactants in incoming wastewater. The study considers two actual treatment plants in a northern Italian City, one treating mostly urban sewage, the second a mixture of urban and industrial wastewater. A comparative assessment of the two plants was performed in laboratory conditions, in order to understand the effects of these exogenous contaminants on the biological processes, and possibly define management and operational criteria for process recovery in the case of renewed actual contamination. Pilot processes of the two plants were run at first, considering the actual design and normal influent conditions of the facilities, then, under stress conditions, by adding the external contaminants at known concentrations to the feed, performing process functionality observations and toxicity tests, and determining the qualitative and quantitative characteristics of the activated sludge biomass. Considerations on processes performance and biocenosis modifications due to pollutants contents are drawn. A discussion on possible effects mitigation strategies is included.

A case of early Wisconsinan “over-chill”: New radiocarbon evidence for early extirpation of western camel (Camelops hesternus) in eastern Beringia

There are comparatively few fossils that document the presence of the Pleistocene western camel (Camelops hesternus) in the unglaciated regions of Alaska and Yukon, northwestern North America (eastern Beringia). It has been previously reported on the basis of stratigraphic and radiocarbon data that this species was present within this region from the Sangamonian interglaciation (Marine Isotope Stage (MIS) 5) through the Last Glacial Maximum (LGM, MIS 2). However, the continued presence of western camel through the LGM is at odds with its ecological preferences as inferred from more southerly parts of the continent. Here we report 43 new radiocarbon dates on 34 western camel fossils from Alaska and Yukon, including specimens that have been dated previously. To minimize exogenous carbon contamination, we utilized either ultrafiltered collagen or single amino acid (hydroxyproline) methodologies in conducting the analyses. All samples, including previously reported specimens with finite ages, yielded ages that were either non-finite or close to the effective limit of radiocarbon dating. These results indicate that dates implying local presence of western camels in Alaska and Yukon during full-glacial conditions of MIS 2 are erroneous by as much as several tens of millennia, probably because of carbon contamination from glue or varnish used in fossil preparation and conservation. The revised radiocarbon chronology, together with other evidence, indicates that western camels were only able to occupy eastern Beringia only during Pleistocene interglaciations such as MIS 5, when forests and shrublands became the dominant regional biomes. The subsequent transition to cold, arid full-glacial conditions during the early Wisconsinan glaciation (MIS 4) around 75 000 years ago created unfavorable environmental conditions, eliminated browse, and led to their local extirpation in eastern Beringia. After their complete population loss in the Arctic and Subarctic, the range of western camels was restricted to the temperate mid-continent, where they eventually went extinct ∼13 000 years ago.

Deep-Sea Hydrothermal Vent Viruses Compensate for Microbial Metabolism in Virus-Host Interactions.

ABSTRACTViruses are believed to be responsible for the mortality of host organisms. However, some recent investigations reveal that viruses may be essential for host survival. To date, it remains unclear whether viruses are beneficial or harmful to their hosts. To reveal the roles of viruses in the virus-host interactions, viromes and microbiomes of sediment samples from three deep-sea hydrothermal vents were explored in this study. To exclude the influence of exogenous DNAs on viromes, the virus particles were purified with nuclease (DNase I and RNase A) treatments and cesium chloride density gradient centrifugation. The metagenomic analysis of viromes without exogenous DNA contamination and microbiomes of vent samples indicated that viruses had compensation effects on the metabolisms of their host microorganisms. Viral genes not only participated in most of the microbial metabolic pathways but also formed branched pathways in microbial metabolisms, including pyrimidine metabolism; alanine, aspartate, and glutamate metabolism; nitrogen metabolism and assimilation pathways of the two-component system; selenocompound metabolism; aminoacyl-tRNA biosynthesis; and amino sugar and nucleotide sugar metabolism. As is well known, deep-sea hydrothermal vent ecosystems exist in relatively isolated environments which are barely influenced by other ecosystems. The metabolic compensation of hosts mediated by viruses might represent a very important aspect of virus-host interactions.

Mycobiota of Slovak wine grapes with emphasis on aspergillus and penicillium species in the south Slovak wine region

The Southern Slovak wine growing region is warmest part of Slovakia and is suitable for cultivating the grapes for production of wines at high quality. From the eight vineyards were collected 8 samples of wine grapes (white 7, blue 1) during harvesting 2011, 2012 and 2013. The aim of this work was to gain more knowledge about mycobiota on grapes originating from Slovakia, to identify Aspergillus and Penicillium species according to their morphopogy and evaluate the presence of secondary metabolites (also including intracellular and extracellular mycotoxins) produced in in vitro conditions by thin layer chromatography method from fresh grape berries. Fifty wine grapes per bunch (approximately 7 - 8 berries per plate) that showed no symptoms were randomly selected on Dichloran Rose Bengal Chloramphenicol agar medium. The plates were then incubated aerobically at 25 ±1 °C for 5 to 7 days in the dark. Of these samples were identified 17 genera. One hundred percent of samples were colonies by the genus Penicillium and 75% by the genus Aspergillus. During the survey, 135 isolates belonging to 9 Penicillium species (P. aurantiogriseum, P. canescens, P. citrinum, P. crustosum, P. decumbens, P. expansum, P. funiculosum, P. chrysogenum and P. purpurogenum) and 26 isolates belonging to 3 Aspergillus species (A. clavatus, A. flavus and A. section Nigri) were isolated and identified from exogenous contamination. The main occurring penicillium species of the samples were P. expansum (37.5% Fr), followed P. citrinum, P. chrysogenum and P. crustosum (25% Fr). The main occurring aspergillus species of the samples were A. section Nigri (62.5%). Eight potentially toxigenic species were tested for their toxigenic ability. It was confirmed the production of various mycotoxins such as aflatoxin B1, citrinin, patulin, cyclopiazonic acid, penitrem A and roquefortin C. Out of 34 strains, 56% produced at least one mycotoxin.

Isolation, identification, and hexon gene characterization of fowl adenoviruses from a contaminated live Newcastle disease virus vaccine

To investigate the possible causes of the massive spread of fowl adenovirus (FAdV) infection among chickens in recent years in China, 32 batches of live-virus vaccines were tested for contamination with FAdV by PCR. Among these, 1 live Newcastle disease virus (NDV) vaccine of the LaSota strain was demonstrated to be positive for contamination. The amplified hexon gene exhibited 99.8% identity with a recent Chinese field isolate (JSJ13) of FAdV-4. The positive LaSota vaccine was first neutralized with anti-NDV serum and then inoculated into specific pathogen-free embryos at embryonic day 5 through the yolk sac for isolation of the contaminated FAdV. The same hexon gene bands were amplified from extracted DNA of the liver tissues and chicken embryo allantoic fluid of the inoculated embryos, indicating the replication and isolation of the FAdV-4 virus strain that had contaminated the vaccine. This represents the first report of FAdV-4 contamination in a live vaccine for poultry in China. These findings suggest that contamination of live vaccine might represent one of the most important causes of massive outbreaks of FAdV infection among chickens and indicate that FAdV should therefore be included in the regular monitoring list for the detection of exogenous viral contamination of attenuated vaccines for poultry.

Industrial comminution of different Al scrap

The comminution of different industrial scale Al scrap, namely Al bus bar plates, turnings and chips, was investigated for its potential as processing route to fabricate powders for the powder metallurgy (PM) supply chain. The proposed processing route included a roughening stage to pre-process coarse Al scrap followed by a comminution stage to generate a wide distribution of pulverized granules and powders. The roughening process effectively refined the size and microstructure of the scrap particles but it also induced Fe contamination of the feedstocks. Quantification of the exogenous contamination accumulated during storage prior to comminution amounted to 20.79±0.06wt% for the pre-treated plates, 8.47±0.05wt% for the pre-treated turnings and 0.54±0.02wt% for the chips. The comminution process of each feedstock was characterized by their residence time which controlled the particle size distribution, morphology as well as the extent of Fe, Mn and Si contamination. Upon screening, the powder fraction smaller than 106μm of each pulverized feedstock was characterized and exhibited a passivation layer thickness and Al2O3 dispersoids content of ~9.8nm and 15.34±0.23wt% Al2O3 for the pre-treated plates, ~9.5nm and 10.07±0.18wt% Al2O3 for the pre-treated turnings and ~6.8nm and 2.13±0.11wt% Al2O3 for the chips, respectively. In addition, the presence of nanoscale grains was highlighted within all pulverized powders. Ultimately, the pulverized powders prepared from each scrap feedstock were found suitable for the PM supply chain provided process improvements were achieved.

Development of suitable method for large-scale urinary glucocorticoid analysis by liquid chromatography-mass spectrometry.

Levels of urinary glucocorticoids and their concentration ratios have been analyzed as potential markers for various pathological statuses. Large-scale studies may possibly accelerate the investigations; however, a suitable method needs to be established. Analytical conditions for measurement of urinary glucocorticoids with LCMS were examined. Electrospray ionization in the positive ion mode was applied for detection of cortisol (precursor>product ion: 363.3>121.0), cortisol-d4 (internal standard, IS, 367.4>121.1), and cortisone (361.2>163.2). To maximize ionization, acetic acid-ammonium acetate buffer (18mM) at pH 5.3 was employed as eluent A. A C18 column (100mm×2.1mm, 2.7μm) at 50°C was used for the 9.5min binary gradient separation starting with 60% eluent A with methanol being eluent B. Linear correlations were observed between the concentrations and the peak areas in the concentration range of 1-300ng/mL with correlation coefficients (r) of 0.998 and 0.997 for cortisol and cortisone, respectively, without IS adjustment, and 0.999 with IS adjustment for both cortisol and cortisone. Solid-phase extraction (SPE) using a 2mL centrifuge column was performed for the urine samples, with the original and final volumes being 100μL. The SPE of 12 urine specimens could be performed within 30min. The effect of the sample matrix on the quantification of endogenous compounds present in the urine extract was limited (coefficient of variation (CV) of IS-adjusted matrix factor: 4.4-8.1%; urine extracts of 8 individuals); however, substantial peak reduction of cortisol was observed at low concentrations. Exogenous contaminants originating from the SPE centrifuge column seemed to be a main cause for this phenomenon because the pure-water extract showed similar peak reduction. A recovery of ∼50% was obtained for both cortisol and cortisone. Adjustment with the IS improved the apparent recovery, with ∼100% being obtained for both cortisol and cortisone. The recovery rate decreased when the urine samples were concentrated in the SPE step; the reduction was greater for cortisol than for cortisone. The lower limit of quantification (LLOQ) was set at 2.5ng/mL when the injection volume was 10μL, based on the reproducibility of the standards which were measured (CV of 12 repetitions: 10.1% for 0.5ng/mL cortisol and 19.6% for 1ng/mL cortisone), the matrix effect (-55% at 2ng/mL concentrations of cortisol), and the recovery rate (∼50%). Furthermore an alternative approach for preparation of the cortisol standards was required for low concentration range (2.5-20ng/mL) because of the effect of the matrix. Degradation of original urine specimens at room temperature was minimal during the first 24h. The extracted urine samples degraded over time; however, their concentrations were corrected with the IS, allowing for analysis up to 5days after extraction. In conclusion, an analytical method for urinary glucocorticoids was established, which is fast, sensitive, and well suited for practical application to large-scale study.

Abiotic environmental conditions for germination and development of gametophytes of Cyathea phalerata Mart. (Cyatheaceae)

ABSTRACT In order to successfully establish themselves in their natural environment, ferns need habitats with abiotic conditions that are suitable for spore germination and gametophyte development. The objective of this study was to assess the influence of abiotic factors on the initial development of Cyathea phalerata cultivated in vitro. Spore germination and gametophyte development were assessed under varying conditions of surface sterilization, pH, temperature and photoperiod. Exogenous contamination was eliminated by sterilizing spores with 2.5 % NaClO for 15 min and sowing them into a culture medium supplemented with nystatin. Spores germinated at all pHs tested. Gametophytic development was faster in acidic pHs. Cultures at 25 °C exhibited the highest percentages of germination and laminar gametophytes. The species produced its highest percentages of gametophytes in cultures with photoperiods between 6 and 18 h. The optimal abiotic conditions found here for in vitro development of C. phalerata are similar to those found in its natural habitat. The southern limit of this species to north of the 30th parallel in Rio Grande do Sul, Brazil, may be because further south spores do not encounter the ideal combined conditions of temperature, pH and photoperiod determined in the laboratory.

Manufacture of low-benzo(a)pyrene sesame seed (Sesamum indicum L.) oil using a self-designed apparatus.

The aim of this study was to lower benzo(a)pyrene (BaP) contents in sesame seed oil (SSO) during manufacture by using a self-designed apparatus, to determine its optimal conditions, and to analyze antioxidants in SSO which might be related to BaP content reduction. Washing and spin-drying steps reduce exogenous BaP contamination, and the reduced moisture in seeds lowered BaP content in final SSO. A ventilation system in the roasting step inhibits BaP formation and reabsorption, followed by a controlled compression step. The optimal condition, a single washing cycle with 2-min spin-drying, 1350-rpm ventilation, and a single compression cycle, reduced the BaP content in SSO to 2.93 μg/kg, where the raw seeds had been spiked with 10-μg/kg BaP. Total phenolic contents showed a reversal pattern to the distribution of BaP contents. Sesamol and sesamolin were quantified by a high performance liquid chromatography-ultraviolet detector, and it was suggested that sesamol which is a strong antioxidant might have prevented BaP formation during the roasting step. This study enabled the commercial production of low-BaP SSO, and the data could be used in further investigations of the BaP content reduction mechanism with quantitative chemical analysis of the SSO composition.

Simultaneous determination of endogenous hormones and exogenous contaminants in infant formula powdered milk by salting-out assisted liquid–liquid extraction combined with solid-phase extraction purification and UPLC-MS/MS

A robust and rapid UPLC-MS/MS method was developed for the simultaneous determination of endogenous hormones and exogenous contaminants in infant formula powdered milk.