On-line High-performance Liquid Chromatography Research Articles

A study on the impact of industrial-scale refining on olive oil and olive pomace oil contamination with mineral oils

Mineral oil hydrocarbons (MOH), including saturated (MOSH) and aromatic (MOAH) hydrocarbons, are contaminants of petrogenic origin. On-line high-performance liquid chromatography (HPLC) – gas chromatography (GC) – flame ionization detector (FID) was used for determining MOH in olive oils (OOs) and olive pomace oils (OPOs) at different stages of the refining process and in samples from the Italian market. Deodorization reduced contamination by about 30 %, resulting in a significant reduction of endogenous n-alkanes generally up to n-C31. Comprehensive GC coupled to quadrupole time-of-flight (QTOF) mass spectrometry (MS) allowed investigating the effect of bleaching on a sample of OPO naturally contaminated with alkylated PAHs, demonstrating the removal capacity of this refining step on potentially carcinogenic genotoxic compounds derived from MOH contamination. OOs from the market contained on average 33.1 mg/kg of MOSH n-C10–50 and 3.3 mg/kg of MOAH, while OPOs contained on average 160.7 and 36.1 mg/kg of MOSH and MOAH, respectively.

An efficient microchip electromembrane extraction online with high-performance liquid chromatography for the measurement of nicotine in high consumption vegetables.

Nicotine, a highly addictive substance, is naturally produced in the Solanaceae family of plants, particularly tobacco. The presence of nicotine in plant foods has adverse effects on the lungs, kidneys, heart, and reproductive system. A novel three-phase microchip flat electromembrane coupled with online high-performance liquid chromatography (HPLC) was developed to analyze nicotine in tomato, mushroom, eggplant, bell pepper, and red pepper. The microchip was connected to the HPLC in online mode. All effective variables were optimized to achieve the best extraction response. The use of electric potential and 2-nitrophenyl octyl ether -5% di(2-ethylhexyl) phosphate as a modified supported liquid membrane (SLM) increased the sensitivity and selectivity. The optimal extraction voltage, extraction time, and ion balance were 40 V, 10 min and 0, respectively. The dynamic linear range was 0.5-1000 ng g-1. The obtained recovery, relative standard deviation, and enrichment factor were 98%, 7%, and 35, respectively. The limits of detection 0.4 ng g-1 and the limits of quantification were obtained 1.3 ng g-1. The highest (105.0 ng g-1) and lowest (3.4 ng g-1) concentrations of nicotine were obtained for eggplant and tomato, respectively. Selective electromembrane extraction of nicotine from the donor phase to the acceptor phase was performed by optimizing the main variables influencing the method mechanism. The new channel design in this analytical system and online injection increased efficiency, stability, and repeatability. The results revealed that this method is capable for the efficient determination of trace amount of nicotine in edible vegetables.

Realization of digital twin for dynamic control towardsample variation of ion exchange chromatography in antibody separation.

Digital twin (DT) is a virtual and digital representation of physical objects or processes. In this paper, this concept is applied to dynamic control of the collection window in the ion exchange chromatography (IEC) towardsample variations. A possible structure of a feedforward model-based control DT system was proposed. Initially, a precise IEC mechanistic model was established through experiments, model fitting, and validation. The average root mean square error (RMSE) of fitting and validation was 8.1% and 7.4%, respectively. Then a model-based gradient optimization was performed, resulting in a 70.0% yield with a remarkable 11.2% increase. Subsequently, the DT was established by systematically integrating the model, chromatography system, online high-performance liquid chromatography, and a server computer. The DT was validated under varying load conditions. The results demonstrated that the DT could offer an accurate control with acidic variants proportion and yield difference of less than 2% compared to the offline analysis. The embedding mechanistic model also showed a positive predictive performance with an average RMSE of 11.7% during theDT test under >10% sample variation. Practical scenario tests indicated that tightening the control target could further enhance the DT robustness, achieving over 98% success rate with an average yield of 72.7%. The results demonstrated that the constructed DT could accurately mimic real-world situations and perform an automated and flexible pooling in IEC. Additionally, a detailed methodology for applying DT was summarized.

An analytical framework combining online high-performance liquid chromatography methodologies and biological properties of different extracts of Leonurus cardiaca.

Little or no information is available concerning online high-performance liquid chromatography (HPLC) antioxidants and the antibiofilm effect of Leonurus cardiaca. Five distinct extractions of methanolic, ethyl acetate, dichloromethane, hexane, and water were obtained from L. cardiaca. In the online-HPLC-antioxidant analysis of all examined samples, rosmarinic acid emerged as the primary antioxidant, registering concentrations ranging from 6 to 15ppm at wavelengths of 517 and 734nm. Notably, the water extract exhibited robust antioxidant activity In vitro. Regarding acetylcholinesterase and butrylcholinesterase inhibition, the n-hexane extract exhibited superior inhibition with values of 3.08 and 5.83 galanthamine equivalent, respectively. Except for the water extract, all tested extracts (at a concentration of 20μg/mL) exhibited substantial inhibitory activity against biofilm formation, in many cases superior to 80%, and reached even 94.52% againstEscherichia coli. Although less vigorous, the extracts also acted against the mature biofilm (inhibition up 76.50% againstStaphylococcus aureus). They could work against the metabolism inside an immature and mature biofilm, with inhibition percentages up to 93.18% (vs.Pseudomonas aeruginosa) and 76.50% (vs.Acinetobacter baumannii), respectively. Considering its significant antioxidants, enzyme inhibition, and antimicrobial activity, L. cardiaca emerges as a promising candidate for therapeutic potential.

Endogenous n-Alkanes in Vegetable Oils: Validation of a Rapid Offline SPE-GC-FID Method, Comparison with Online LC-GC-FID and Potential for Olive Oil Quality Control.

The potential of endogenous n-alkane profiling for the assessment of extra virgin olive oils (EVOO) adulteration (blends with cheaper vegetable oils) has been studied by relatively few authors. Analytical methods used for this purpose often involve tedious and solvent-intensive sample preparation prior to analytical determination, making them unattractive. A rapid and solvent-sparing offline solid phase extraction (SPE) gas chromatography (GC) flame ionization detection (FID) method for the determination of endogenous n-alkanes in vegetable oils was, therefore, optimized and validated. The optimized method demonstrated good performance characteristics in terms of linearity (R2 > 0.999), recovery (on average 94%), and repeatability (residual standard deviation, RSD < 11.9%). The results were comparable to those obtained with online high-performance liquid chromatography (HPLC)-GC- FID ( RSD < 5.1%). As an example of an application to prove the potentiality of endogenous n-alkanes in revealing frauds, the data set obtained from 16 EVOO, 9 avocado oils (AVO), and 13 sunflower oils (SFO), purchased from the market, was subjected to statistical analysis and principal component analysis. Two powerful indices, namely (n-C29 + n-C31)/(n-C25 + n-C26) and n-C29/n-C25, were found to reveal the addition of 2% SFO in EVOO and 5% AVO in EVOO, respectively. Further studies are needed to confirm the validity of these promising indices.

Target Discovery of Flavonoids from Elymus nutans Griseb Using Medium- and High-Pressure Liquid Chromatography Combined with Online High-Performance Liquid Chromatography–1,1-diphenyl-2-picrylhydrazyl Detection

Forage-based nutrients constitute the main forage value of forage grass. Elymus nutans Griseb possesses a wide ecological adaptability, enhanced crude protein content, good palatability, and excellent genes. Herein, employing medium- (MPLC) and high-pressure liquid chromatography (HPLC), along with online HPLC-DPPH (OHD)-based identification, two primary radical scavenging compounds were extracted and identified from the methanolic extract of Elymus nutans Griseb. With a starting material of 300 g of Elymus nutans Griseb, 5.95 g of the target DPPH suppressors fraction (Fr6) was separated following one cycle of MCI GEL® CHP20P medium pressure liquid chromatography. A Kromasil 100-5-Phenyl column was subsequently employed for further purification of the fraction, which yielded 432.16 mg of Fr62 (7.26% recovery) and 489.01 mg of Fr63 (8.22% recovery). The target compounds were then assessed based on their structure and purity, and two compounds (salcolin A and tricin) were extracted with &gt; 95% purity. This newly designed procedure was highly effective for the targeted flavonoids, and high-purity radical scavenger extraction from forage extracts. This methodology can potentially provide a scientific basis for their quality evaluation.

A study on the impact of harvesting operations on the mineral oil contamination of olive oils

During the 2020–21 olive oil campaign, the contribution of harvesting operations to mineral oil saturated (MOSH) and aromatic hydrocarbon (MOAH) contamination was studied. Oils extracted from hand-picked olives (15 different olive groves) generally had background MOSH (<2.7 mg/kg), and no quantifiable MOAH. In 40% of the cases, an important contamination increase was observed after harvesting operations. Except for one sample (325.8 and 111.0 mg/kg of MOSH and MOAH, respectively), other samples reached 4.3–33.7 mg/kg of MOSH and 1.1–11.3 mg/kg of MOAH. Accidental leaks of lubricants and/or contact with lubricated mechanical parts, were identified as important sources of contamination. Chromatographic traces obtained by on-line high-performance liquid chromatography (HPLC)-gas chromatography (GC)-flame ionization detection (FID) allowed for source identification. A comprehensive two-dimensional gas chromatographic platform (GC × GC) with parallel FID/MS detection was implemented for confirmation and to attempt the characterization of the contaminations. Good harvesting practices are suggested to minimize contamination risks.

Mineral oil contamination in basil pesto from the Italian market: Ingredient contribution and market survey

Mineral oil hydrocarbons (MOH) are complex mixtures of saturated hydrocarbons (MOSH) which bioaccumulate in human tissues, and aromatic hydrocarbons (MOAH) which include genotoxic and carcinogenic substances. This work aimed to investigate these emerging food contaminants in basil pesto from the Italian market, and ingredient contribution to the final product contamination. Twelve market samples and 4 additional samples (and related ingredients) produced in a pilot plant, were analyzed by on-line high-performance liquid chromatography (HPLC)- gas chromatography (GC), preceded by matrix-tailored sample preparation. Method performance was good with recoveries from 94% to 109%, residual standard deviations (RSD) less than 10%, and a limit of quantitation (LOQ) of 0.5 mg/kg (for total MOAH). Vegetable oils, followed by cashews, which showed a similar contamination profile to foods transported in jute bags, were the major contributors to contamination, while cheese and basil contribution was negligible. Sunflower oil alone accounted for more than 80–85% of the total contamination. Samples from the Italian market had an average of 5.6 and 0.6 mg/kg of MOSH and MOAH, respectively, and a contamination profile that confirmed that the main contributors to total contamination were sunflower oil and cashews. Mitigation actions should be directed toward careful control of these two ingredients.

Assignation of inorganic mercury and methylmercury mass fractions in a soil matrix certified reference material by two analytical methodologies based on species-specific isotope dilution mass spectrometry and chromatographic separation.

Assignment of inorganic mercury and methyl mercury mass fractions at an ultratrace level in soil certified reference material EnvCRM 03 with a complex matrix composition was undertaken. Inorganic mercury and methyl mercury contents by species-specific isotope dilution inductively coupled plasma mass spectrometry with on-line high-performance liquid chromatography or with classical off-line chromatography were established. Different extraction protocols: sequential extraction ((1) H2 SO4 /KBr/CuSO4 ; (2) dichloromethane; (3) Na2 S2 O3 ) or one-step extraction (diluted HCl) in solid-liquid systems were verified. Sequential extraction allowed quantification and separation of inorganic mercury and methyl mercury on HPLC column in one chromatographic run and were found to be (316 ± 10) μg/kg (U = 3.2%, k = 2) and (0.53 ± 0.02) μg/kg (U = 3.8%, k = 2), respectively. Extraction by diluted HCl and application of classical off-line chromatography led to the separation of methyl mercury from predominant inorganic mercury form and was found to be (0.54 ± 0.03) μg/kg (U = 5.4%, k = 2). To the best-obtained literature knowledge, there was no available soil material aimed for speciation analysis of inorganic mercury and methyl mercury so far. Both developed analytical methodologies were found to be equally sensitive and could be successfully applied for mercury species determination in samples with the complex matrix.

Online HPLC–HRMS Platform: The Next-Generation Process Analytical Technology Tool for Real-Time Monitoring of Antibody Quality Attributes in Biopharmaceutical Processes

Online monitoring of critical quality attributes (CQAs) directly within the bioreactor can provide the basis for advanced processing of therapeutics production, including automated real-time monitoring, feedback control process intensification, smart manufacturing, and real-time release testing. This paper presents recent developments in online high performance liquid chromatography–high-resolution mass spectrometry (HPLC–HRMS) platforms as a promising process analytical technology (PAT) tool for real-time monitoring of antibody quality attributes (QAs) in biopharmaceutical processes. This technology can be used to monitor multiple CQAs and process parameters during cell culture production, enabling real-time decisions.

Brass wires with different surface wettability used for in-tube solid-phase microextraction

Metal wires have been widely used as substrates for solid-phase microextraction (SPME) fibers instead of commonly fragile silica fibers, but complicated coating modification of their surface is required. Herein, a series of brass wires were soaked in an acidic iron trichloride solution with ultrasonication, which etched the brass surface through a redox reaction. The surface wettability of the pristine brass wire was transformed from hydrophobic to hydrophilic owing to the formation of micro/nanoscale hierarchical structures. After modification with n-octadecanethiol (ODT) and 2-naphthalenethiol (NT), respectively, both wires exhibited superhydrophobicity. Characterization of the resulting wires was conducted using SEM and EDS, and the surface wettability was measured by a contact angle goniometer using identical brass meshes. To build an in-tube SPME–high-performance liquid chromatography (HPLC) online system, the extraction tube was connected with HPLC equipment by replacing the sample loop of a six-port valve. Four types of wires, including the pristine hydrophobic brass wire, the hydrophilic wire after chemical etching, and both superhydrophobic wires, were comparatively applied to the extraction of six estrogens. The optimized extraction conditions were a sample volume of 60 mL, an injection rate of 2 mL/min, and a desorption time of 2 min at a flow rate of 1 mL/min. The results showed that the highest estrogen extraction efficiency was obtained using the superhydrophobic wire modified by NT, with the enrichment factors in the range of 36–350. Furthermore, the superhydrophobic NT wire exhibited a higher extraction efficiency than the ODT wire with identical superhydrophobicity. This demonstrated that the higher extraction efficiency was mainly dependent on π–π interactions between the sorbent containing naphthalene rings and the target compounds containing benzene rings, rather than surface wettability.

Electrooxidation of Formamidine Disulfide Simultaneously Investigated by On-Line High Performance Liquid Chromatography and Cyclic Voltammetry.

The electro‐oxidation of formamidine disulfide, an important sulfur‐containing compound, was simultaneously investigated with on‐line high‐performance liquid chromatography and cyclic voltammetry. Using a home‐made microporous sampler located at the electrode interface, the solution on the electrode surface was in situ sampled and analyzed. The electrochemical scanning was synchronously performed, which allowed the electro‐oxidation products to be detected at a given potential. The main products on the surface of platinum electrode were found to be thiourea, formamidine sulfinic acid, cyanamide, and elemental sulfur. Forced convection arising from the sampling played an important role in the electrochemical oxidation. The extraction of electrode surface solution promoted the renewal of reactant and its intermediates, which induced the change of cyclic voltammetry curve. The forced convection also contributed to the redox peak current of the species on the cyclic voltammetry curves through the change of concentration of reactant and its intermediates. This technique can help to explore the reaction mechanism of complex electrochemical reactions.

Survey of mineral oil hydrocarbons in Chinese commercial complementary foods for infants and young children

ABSTRACT Recently, mineral oil hydrocarbons (MOH) in various foods have raised significant concern, especially for infants and young children due to their potential adverse health effects. Two fractions can be distinguished by certain analytical techniques, mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). The toxicological profile of MOSH and MOAH differs greatly. The toxicity of MOSH is linked with long-term accumulation of some hydrocarbons. MOAH with three to seven, non- or simple-alkylated, aromatic rings may be mutagenic and carcinogenic. However, data on the occurrence of mineral oils in commercial complementary foods for infants and young children are lacking in China. In the present study, 100 commercial food samples were collected, including 26 pureed or paste canned foods, 21 high-protein ground cereal foods (rice flour), 25 raw cereal foods (noodles), and 28 cereal-based molar sticks and biscuits. The content of MOSH and MOAH in those samples was determined by optimised sample preparation methods combined with on-line high-performance liquid chromatography coupled with gas chromatography and flame ionisation detector (HPLC-GC-FID), with a limit of quantification of 0.5 mg/kg. The results indicated that there were no MOAH detected in any of the foods, but MOSH and polyolefin oligomeric saturated hydrocarbons (POSH) existed in most of the food samples, at <0.5–23.68 mg/kg. Moreover, the data and chromatograms of the MOSH and POSH also indicated that these contaminants were closely correlated to their ingredients and manufacturers. The current study provides basic data to understand MOH exposure and consequent health impact.

Research Progress of Analysis of Mineral Oil Hydrocarbons using On-line High Performance Liquid Chromatography Coupled with Gas Chromatography

Abstract In the past decades, the application of on-line high performance liquid chromatography coupled with gas chromatography (HPLC-GC) has been rapidly developed for the quantitative analysis of mineral oil hydrocarbons (MOH). MOH are derived from petroleum and synthetic fuels, and cover a large range of boiling points, mainly consisting of mineral oil saturated hydrocarbons (MOSH) and aromatic hydrocarbons (MOAH). MOH can migrate into food and environment through a variety of pathways, consequently impose an adverse impact on human health. However, the analysis of MOH is challenging due to the limited selectivity and sensitivity of hydrogen flame ionization detector (FID). On-line HPLC-GC combines the high separation efficiency of HPLC with the equal-carbon-response detection of GC-FID, which solves the problems associated with selectivity and sensitivity of MOH analysis. The innovation of the retention gap, Y-piece interface, and solvent vapor exit (SVE) with which the HPLC-GC is equipped enables large-volume injection into GC-FID. By allowing the elution fractions from HPLC to be completely transferred into the GC, the analytical sensitivity of the MOH is enhanced by more than two orders of magnitude, and the contaminants introduced are minimized during the analytical procedure, ensuring the reproducibility and accuracy of the MOH analysis. In this paper, the research history of the interfaces used in on-line HPLC-GC and the matching conditions between HPLC and GC were described in detail, and the sample preparation methods for the removal of interferences and the enrichment of MOH based on HPLC-GC were reviewed. In addition, the limitations of HPLC-GC were summarized, and the future applications of this technology and the trends in the development of MOH analysis were prospected.

Targeted isolation of 1,1-diphenyl-2-picrylhydrazyl inhibitors from Saxifraga atrata using medium- and high- pressure liquid chromatography combined with online high performance liquid chromatography–1,1-diphenyl-2- picrylhydrazyl detection

Traditional Tibetan medicine (TTM) is a valuable source of novel therapeutic lead molecules inspired by natural products (NPs). The health benefits of Saxifraga atrata are well documented in TTM, but reports on its chemical composition are limited, most likely due to the complicated purification process. Herein, target separation and identification of 4 main radical scavenging compounds from the methanolic extract of S. atrata was were performed using medium- and high-pressure liquid chromatography coupled with online HPLC-DPPH detection. The sample was pretreated using medium pressure liquid chromatography with MCI GELⓇ CHP20P styrene-divinylbenzene beads as a stationary phase, yielding 1.4 g of the target DPPH inhibitors (Fr4, 11.9% recovery). The compounds were further purified and isolated using HPLC on RP-C18 (ReproSil-Pur C18 AQ) followed by HILIC (Click XIon) column separation, resulting in 2.8 mg of fraction Fr4-1-1, 6.8 mg of fraction Fr4-2, 244.9 mg of the Fr4-3-1 sample, and 38.3 mg of Fr4-4-1. The structure and purity of the target compounds were determined, and four compounds (ethyl gallate, 11-O-galloylbergenin, rutin and isoquercitrin) were isolated with >95% purity. The developed methodology is efficient for targeted isolation of high-purity radical scavengers from NP extracts and could be used for rapid identification and isolation of DPPH inhibitors from various NPs.

Migration of Polypropylene Oligomers into Ready-to-Eat Vegetable Soups.

Polyolefin oligomeric hydrocarbons (POH) are non-intentionally added substances (NIAS) which mainly reside in the polymer (PE, PP) as a consequence of the polymerization process, and that under favorable conditions (high fat content, high temperature, and long contact time) may migrate at high amount from the packaging into the food. The food industry offers a wide range of ready-to-eat products, among these, vegetable soups designed to be stored at refrigeration temperature (for times around 6 weeks), and in most cases to be heated for a few minutes in a microwave oven (into the original container, mostly of PP) before consumption. The present work aimed to study for the first-time migration of POH during the shelf life of these products, including storage at refrigeration temperature and after microwave heating. On-line high-performance liquid chromatography (HPLC)-gas chromatography (GC), followed by flame ionization detection (FID), was applied for POH analysis in a number of ready-to-eat products purchased from the Italian market. Microwave heating determined a variable POH increase ranging from 0.1 to 6.2 mg/kg. Parameters possibly affecting migration such as fat content and heating time were also studied.

Associations of dietary intakes and serum levels of folate and vitamin B-12 with methylation of inorganic arsenic in Uruguayan children: Comparison of findings and implications for future research

BackgroundIn the human body, inorganic arsenic (iAs) is methylated via the one-carbon cycle to form monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). Lower proportions of iAs and MMA, and higher proportions of DMA in urine indicate efficient methylation; formation of DMA is thought to detoxify iAs and MMA. Studies on folate, vitamin B-12 and iAs methylation yield mixed findings, depending on whether folate and vitamin B-12 were assessed from diet, supplements, or using a blood biomarker. ObjectiveFirst, to compare the associations of serum concentrations and estimated intake of folate and vitamin B-12 with indicators of iAs methylation. Second, to highlight the implications of these different B-vitamin assessment techniques on the emerging evidence of the impact of dietary modifications on iAs methylation. MethodsThe study was conducted among ~7-year-old children from Montevideo, Uruguay. Serum folate and vitamin B-12 levels were measured on the Horiba ABX Pentra 400 analyzer; urinary arsenic was measured using High-Performance Liquid Chromatography on-line with Inductively Coupled Plasma Mass Spectrometry. Dietary intakes were assessed using the average of two 24-h dietary recalls. Linear regressions assessed the associations of serum levels, and dietary intakes of folate (n = 237) and vitamin B-12 (n = 217) with indicators of iAs methylation. Models were adjusted for age, sex, body mass index, total urinary arsenic, and rice intake. ResultsSerum folate and vitamin B-12 levels were above the adequacy threshold for 99% of the participants. No associations were observed between serum folate, serum vitamin B-12, or vitamin B-12 intake and iAs methylation. Folate intake was inversely associated with urinary %MMA [β (95% confidence interval): −1.04 (−1.89, −0.18)]. ConclusionAdditional studies on the role of B-vitamins in iAs methylation are needed to develop a deeper understanding of the implications of assessing folate and vitamin B-12 intake compared to the use of biomarkers. Where possible, both methods should be employed because they reflect different exposure windows and inherent measurement error, and if used individually, will likely continue to contribute to lack of consensus.

One injection to profile the chemical composition and dual-antioxidation activities of Rosa chinensis Jacq.

An on-line high-performance liquid chromatography−diode-array-detector−electrospray ionization−ion-trap−time-of-flight−mass spectrometry−total antioxidant capacity detection (HPLC−DAD−ESI−IT−TOF−MS−TACD) system was applied for the identification and evaluation of antioxidants in Rosa chinensis Jacq., an edible flower in food industry and a widely used traditional Chinese medicine. With the help of this platform, the HPLC fingerprint, mass fragmentations, and sample activity profiles against 1,1-diphenylpicryl-2-hydrazyl radical (DPPH•) and ferric reducing antioxidant power (FRAP) were recorded after one injection. Using this technique, 80 compounds were separated and identified by their LC/MS behaviors with the assistance of standard compounds. In addition, 11 different Rosa chinensis Jacq. samples were profiled and then quantified for their DPPH• and FRAP activities. Interestingly, a total of 52 compounds showed antioxidative effects against DPPH• and 61 were active against FRAP. The results demonstrated that the on-line system is a powerful technique for antioxidant discovery in Rosa chinensis Jacq. and other food resources.

Rapid screening of mineral oil aromatic hydrocarbons (MOAH) in grains by fluorescence spectroscopy

On-line high-performance liquid chromatography coupled with gas chromatography with flame ionization detector (LC-GC) has become an important technique for the determination of mineral oil aromatic hydrocarbons (MOAH) in foods. However, the analysis is complicated and time-consuming. The present study aimed to develop a fluorescence spectrophotometry approach for the fast screening of MOAH in grains. A reference material, which is a mixture of diesel oils and lubricants, was selected for MOAH calibration. The excitation/emission wavelength of EX230 nm/EM330 nm was determined and the linear range was 0.125–2.5 mg/kg with an R2 of 0.999. The MOAH content determined by the fluorescence method showed good correlation with that determined by LC-GC (r = 0.946). This result suggested that the performance of these two methods was comparable, and thus fluorescence spectroscopy can be used for screening MOAH. A MOAH content of >0.1 mg/kg in grains could be rapidly determined by fluorescence spectroscopy.

Determinants of phthalate exposure and risk assessment in children from Poland

Phthalates are a group of widely used chemicals and humans are exposed to them in their daily life. Some phthalates may affect the hormonal balance in both children and adults. The aim of this study was to assess the phthalate exposure and its determinants among children at age of 7 years from the Polish Mother and Child Cohort Study (REPRO_PL). 250 urine samples collected in 2014–2015 were analysed for 21 metabolites of 11 parent phthalates using on-line high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). This represents the most extensive set of phthalate metabolites ever determined for Poland. Ten metabolites were quantifiable in 100% of the samples, another eight in >90%. The highest median concentrations were found for the primary monoester metabolites of di-iso-butyl (MiBP, 72.4 μg/l), di-n-butyl (MnBP, 56.3 μg/l) and diethyl (MEP, 42.0 μg/l) phthalate, followed by the sum of di-2-ethylhexyl (ΣDEHP, 89.3 μg/l) and di-iso-nonyl (ΣDiNP, 21.9 μg/l) phthalate metabolites. Metabolite concentrations were higher in children at 7 years than in the same children at age 2 or in their mothers during pregnancy. Generally, phthalate exposures in this study were much higher than exposures reported in other European populations. Multivariate regression models showed that body mass index, place of residence, breastfeeding duration, socio-economic status and parental education were associated with the metabolite levels in the 7-year old children. Daily intake and hazard index calculations revealed that a small percentage of children (around 3–10%) exceeded the tolerable daily intakes established by international institutions such as EFSA and U.S. EPA indicating that these children might be at risk of anti-androgenic effects from the individual and cumulative exposure to phthalates. Thus, further monitoring of this population, by educational programs and follow-up interventions, is required.