Key issues around the evaluation of risks to humans from mineral oils in food and feedstuffs are discussed. MOHs (MOAH and MOSH) occur in food due to intentional use, contamination from environmental ...sources and during transport/processing, or through migration from food contact materials. Problems in setting and enforcing human health guidelines for MOH include uncertainty around MOH toxicity and the specialist expertise needed for analysis of complex food matrices.
Currently, the method of choice for measuring mineral oils is LC-GC-FID, however some complex food matrices also require additional analytical techniques to differentiate between some naturally occurring hydrocarbons and those from other sources, including of petrogenic origin. This requires the skills of an experienced analyst.
Significant toxicological gaps for MOHs prevent robust human health risk assessment and the derivation of guidance values. As food-grade mineral oils are virtually MOAH-free, the key issue explored here is the relevance to humans of liver (micro)granulomas observed in F344 rats following oral intake.
Available data suggest that despite the ubiquitous nature of MOH in the human diet, the prevalence of liver lipogranulomas in the population is low. These are not associated with inflammation and based on current evidence are not considered of human health significance.
•MOHs are complex mixtures, historically characterised on physical properties, not chemical structures/molecular weight.•The method of choice for the routine quantification of mineral oils, LC-GC-FID, is sometimes not sufficient for the characterisation of complex food matrices.•Toxicological studies in F-344 and Sprague-Dawley rats show very different sensitivities to the adverse effects of MOSH.•Differences in sensitivities between rat strains are likely due to variation in absorption and accumulation of MOSH.•Characterisation of MOH used in early toxicity studies is often poor, impacting on their use for evaluating food safety.
► Basics on solvent evaporation for on-line transfer of HPLC fractions. ► HPLC preseparation for MOSH and MOAH. ► HPLC–GC interfaces: conditions for HPLC–GC transfer. ► GC for mineral oil analysis. ► ...Auxiliary tools for mineral oil analysis.
For the analysis of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH), on-line coupled high performance liquid chromatography–gas chromatography–flame ionization detection (HPLC–GC–FID) offers important advantages: it separates MOSH and MOAH in robust manner, enables direct injection of large aliquots of raw extracts (resulting in a low detection limit), avoids contamination of the sample during preparation and is fully automated. This review starts with an overview of the technology, particularly the fundamentals of introducing large volumes of solvent into GC, and their implementation into various transfer techniques. The main part deals with the concepts of MOSH and MOAH analysis, with a thorough discussion of the choices made. It is followed by a description of the method. Finally auxiliary tools are summarized to remove interfering components, enrich the sample in case of a high fat content and obtain additional information about the MOSH and MOAH composition.
Mineral oil aromatic hydrocarbon (MOAH) analysis in foods is a major analytical challenge. Quantification is associated with a high uncertainty. The sources of uncertainty are multiple, but the major ...one is related to data interpretation and integration, which is partially derived from insufficiently efficient sample preparation. Recently, an updated ISO method for the analysis of mineral oil in fats and oils and a standard operating procedure for infant formula analysis have been published. Both methods reported significantly different (up to 1.25) distributions of the internal standards used for quantification (i.e., tri-tert-butyl benzene (TBB) and 2-methyl naphthalene (2-MN)) over the different solvent phases used in the saponification step.
In this work, a microwave-assisted saponification and extraction method was optimized for MOAH analysis to solve the problem related to the MOAH internal standards partition. The paper examines the impact of the solvent mixture used, the concentration of KOH on the partition of TBB and 2-MN, and the effect of the matrix and the washing step to extract the unsaponifiable fraction containing the mineral oils.
The optimized procedure achieved a TBB/2-MN ratio of 1.05 ± 0.01 tested in five different fats and oils, namely, sunflower, rapeseed, coconut, palm, and extra virgin olive oils. The method can significantly contribute to reducing the uncertainty of the MOAH quantification when saponification is applied.
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•Systematic investigation of saponification parameters.•Reduction of the uncertainty of MOAH quantification when saponification is involved.•Optimization of a microwave-assisted saponification and extraction.•Improvement of the reliability of MOAH analysis.
•Upon dermal exposure, mineral oil and waxes are predominantly adsorbed to the stratum corneum.•Only a minor fraction of mineral oil and waxes reach the deeper layer of the skin.•There is no evidence ...that mineral oils or waxes as used in cosmetic applications are percutaneously absorbed.•The cosmetic use of mineral oils and waxes does not present a risk to consumers due to lack of systemic exposure.
Mineral oils and waxes used in cosmetic products, also referred to as “personal care products” outside the European Union, are mixtures of predominantly saturated hydrocarbons consisting of straight-chain, branched and ring structures with carbon chain lengths greater than C16. They are used in skin and lip care cosmetic products due to their excellent skin tolerance as well as their high protecting and cleansing performance and broad viscosity options.
Recently, concerns have been raised regarding potential adverse health effects of mineral oils and waxes from dermal application of cosmetics. In order to be able to assess the risk for the consumer the dermal penetration potential of these ingredients has to be evaluated. The scope and objective of this review are to identify and summarize publicly available literature on the dermal penetration of mineral oils and waxes as used in cosmetic products.
For this purpose, a comprehensive literature search was conducted. A total of 13 in vivo (human, animal) and in vitro studies investigating the dermal penetration of mineral oils and waxes has been identified and analysed. The majority of the substances were dermally adsorbed to the stratum corneum and only a minor fraction reached deeper skin layers. Overall, there is no evidence from the various studies that mineral oils and waxes are percutaneously absorbed and become systemically available. Thus, given the absence of dermal uptake, mineral oils and waxes as used in cosmetic products do not present a risk to the health of the consumer.
► Background information on migration from recycled paperboard. ► Interpretation of chromatograms with various types of mineral oil. ► Integration of MOSH and MOAH in complex chromatograms. ► ...Estimation of measurement uncertainty and limit of quantitation for examples.
Mineral oil hydrocarbons are complex as well as varying mixtures and produce correspondingly complex chromatograms (on-line HPLC–GC-FID as described in Part 1): mostly humps of unresolved components are obtained, sometimes with sharp peaks on top. Chromatograms may also contain peaks of hydrocarbons from other sources which need to be subtracted from the mineral oil components. The review focuses on the interpretation and integration of chromatograms related to food contamination by mineral oil from paperboard boxes (off-set printing inks and recycled fibers), if possible distinguishing between various sources of mineral oil. Typical chromatograms are shown for relevant components and interferences as well as food samples encountered on the market. Details are pointed out which may provide relevant information. Integration is shown for examples of paperboard packaging materials as well as various foods. Finally the uncertainty of the analysis and limit of quantitation are discussed for specific examples. They primarily result from the interpretation of the chromatogram, manually placing the baseline and cuts for taking off extraneous components. Without previous enrichment, the limit of quantitation is between around 0.1mg/kg for foods with a low fat content and 2.5mg/kg for fats and oils. The measurement uncertainty can be kept clearly below 20% for most samples.
•MOSH and MOAH determination in cereal-based products.•Microwave assisted saponification and extraction followed by on-line LC–GC.•Method performance and recovery tests on different ...matrices.•Comparison with other extraction methods.•Applications to dry pasta, bread, biscuits and cakes.
A high throughput, high-sensitivity procedure, involving simultaneous microwave-assisted extraction (MAS) and unsaponifiable extraction, followed by on-line liquid chromatography (LC)–gas chromatography (GC), has been optimised for rapid and efficient extraction and analytical determination of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) in cereal-based products of different composition. MAS has the advantage of eliminating fat before LC–GC analysis, allowing an increase in the amount of sample extract injected, and hence in sensitivity. The proposed method gave practically quantitative recoveries and good repeatability. Among the different cereal-based products analysed (dry semolina and egg pasta, bread, biscuits, and cakes), egg pasta packed in direct contact with recycled paperboard had on average the highest total MOSH level (15.9mgkg−1), followed by cakes (10.4mgkg−1) and bread (7.5mgkg−1). About 50% of the pasta and bread samples and 20% of the biscuits and cake samples had detectable MOAH amounts. The highest concentrations were found in an egg pasta in direct contact with recycled paperboard (3.6mgkg−1) and in a milk bread (3.6mgkg−1).
Mineral oils and waxes are mixtures of predominantly saturated hydrocarbons consisting of straight‐chain, branched and ring structures with carbon chain lengths greater than C14. They have been used ...for many decades in skin and lip care cosmetic products due to their excellent skin tolerance as well as their high protecting and cleansing performance and broad viscosity options. In contrast to vegetable oils, mineral oils are non‐allergenic since they are highly stable and not susceptible to oxidation or rancidity. They have a long history of safe use which is confirmed by clinical and epidemiological data. In Europe, mineral oils are only permitted in cosmetics if compliant with purity specifications on polycyclic aromatic hydrocarbons and safety requirements laid down in the European pharmacopoeia and the EU cosmetics regulation EC/1223/2009. The high quality of these mineral oils is assured by robust quality assurance and a refining/purification process designed to exclude substances with carcinogenic potential and to minimize the presence of mineral oil aromatic hydrocarbons. Given their highly lipophilic properties, mineral oils do not penetrate human skin and, thus, are not systemically bioavailable in the body. Moreover, no significant changes in the skin and no effects on any internal organ system have been reported and attributed to the topical application of refined mineral oils. Regarding potential oral exposure from cosmetic lip care products, Cosmetics Europe, the European trade association for the cosmetics and personal care industry, has advised cosmetic manufacturers to only use mineral oil fractions for which recognized food acceptable daily intake (ADI) values apply. The estimated dose of mineral oils ingested via lip care products contributes to <10% of the ADI value and should therefore be considered of no toxicological concern.
•Present 2D software fails in the MOSH and MOAH integration.•Prototype software was evaluated for both 1D and 2D integration of MOSH and MOAH.•Using the prototype software 1D and 2D results were ...comparable to the expected ones.•A novel LC-GC × GC-ToFMS/FID platform was used for MOSH and MOAH analysis.
The determination of the level of mineral oil contamination in foods is a well-known problem. This class of contaminants is generally divided into mineral oil saturated and aromatic hydrocarbons with different toxicological relevance and analytical challenges. Among the many challenges, data interpretation and integration represent an important source of uncertainty in the results provided by different laboratories leading to a variation evaluated on the order of 20%. The use of multidimensional comprehensive gas chromatography (GC × GC) has been proposed to support the data interpretation but the integration and the reliability of the results using this methodology has never been systematically evaluated. The aim of this work was to assess the integration and quantification performance of a two-dimensional (2D) software. The data were generated using a novel, completely automated platform, namely LC-GC × GC coupled to dual detectors, i.e., time-of-flight mass spectrometer (MS) and flame ionization detector (FID). From a systematic study of the failures of the two-dimensional quantification approach a novel solution was proposed for simplifying and automating the entire process. The novel algorithm was tested on ad hoc created samples (i.e. a paraffin mixture added of n-alkanes) and real-world samples proving the agreement of the results obtained by LC-GC × GC and the traditional mono-dimensional approach. Moreover, the benefits of using an entirely integrated platform were emphasized, particularly regarding the identity confirmation capability of the MS data, which can be easily translated into the 2D FID quantification feature.
► Rapid and sensitive off-line SPE-LVI-GC-FID method for MOSH and MOAH analysis. ► Large volume injection with PTV as an alternative to on-column injection. ► The validated method was proposed as an ...alternative to the on-line LC–GC method. ► The method was applied to different food extracts.
A rapid off-line solid phase extraction-large volume injection-gas chromatography-flame ionisation detection (SPE-LVI-GC-FID) method, based on the use of silver silica gel and low solvent consumption, was developed for mineral oil saturated hydrocarbon (MOSH) and mineral oil aromatic hydrocarbon (MOAH) determination in cardboard and dried foods packaged in cardboard. The SPE method was validated using LVI with a conventional on-column injector and the retention gap technique (which allowed to inject up to 50μL of the sample). Detector response was linear over all the concentration range tested (0.5–250μg/mL), recoveries were practically quantitative, repeatability was good (coefficients of variation lower than 7%) and limit of quantification adequate to quantify the envisioned limit of 0.15mg/kg proposed in Germany for MOAH analysis in food samples packaged in recycled cardboard. Rapid heating of the GC oven allowed to increase sample throughput (3–4 samples per hour) and to enhance sensitivity. The proposed method was used for MOSH and MOAH determination in selected food samples usually commercialised in cardboard packaging. The most contaminated was a tea sample (102.2 and 7.9mg/kg of MOSH and MOAH below n-C25, respectively), followed by a rice and a sugar powder sample, all packaged in recycled cardboard.
Oral exposure to mineral oil may result in a narrow fraction of mineral oil saturated hydrocarbon (MOSH) being retained in tissues. Excess of MOSH hepatic retention may lead to the formation of ...lipogranuloma caused by predominantly multiring cycloalkanes (naphthenics) in a critical range of C25–C35. Although hepatic lipogranuloma is of low pathological concern, MOSH tissue deposition could be minimized by using an oil of similar quality but devoid of naphthenic structures to decrease hepatic retention.
Synthetic Gas to liquid (GTL) oils offer an alternative to petroleum derived mineral oils, because they do not contain naphthenic structures. To demonstrate this point, SD rats were fed either GTL oil (99% iso-alkanes) or naphthenic mineral oil (84% cycloalkanes) at 200 mg/kg bw/day for 90 or 134 days with a recovery group. Liver, fat and mesenteric lymph nodes were analyzed for alkane sub-type levels using Online-HPLC-GC-FID and GCxGC-TOF-MS.
Results indicate that at equal external dose, GTL hydrocarbons result in lower tissue levels and more rapid excretion than MOSH. GTL retained hepatic fractions were also qualitatively different than MOSH constituents. Because chemical composition differences, GTL oil show low absorption and tissue retention potential and thus an advantageous alternative to conventional mineral oil.
•Mineral oil iso-alkane and naphthenics show higher hepatic retention and slower excretion than GTL iso-alkanes.•Structural differences of GTL oil iso-alkanes explain lower gut absorption and faster hepatic elimination.•It is shown that cycloalkanes/naphthenics alkane sub-class are most prone to hepatic retention, which are absent in GTL oils.•Retention of alkane sub-classes in SD rat tissues, including the liver, is qualitatively comparable to that seen in humans.•Both SD-rat and human tissues show the same pattern for n-alkane distribution where the F-344 notably shows a deviant pattern.•Low retention of GTL oil offers an alternative in food applications and vaccine adjuvants where MOSH residues are not desired.
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