1,721,003 research outputs found
Mineral oil hydrocarbons: development/optimization of analytical methods, investigation of migration from food packaging into semolina and egg pasta, and occurrence in human tissues.
Full text linkMineral oil is a complex mixture of compounds, primarily manufactured from crude petroleum through distillation processes and various refining steps, mainly consisting of MOSH (mineral oil saturated hydrocarbons), including n-alkanes, isoalkanes and cycloalkanes (naphtenes), and MOAH (mineral oil aromatic hydrocarbons), mostly alkylated. The MOSH fraction may include polyolefin oligomeric saturated hydrocarbons (POSH), oligomers of polyolefins, which can migrate from plastic bags, heat-sealable layers and other laminates as well as adhesives and plasticizers.
Mineral oils hydrocarbons present in printing inks and recycled paper are sufficiently volatile (< n-C24) to migrate from the packaging to the food through the gas phase. Exposure to mineral oil hydrocarbons via packaging and some foods may pose a human health hazard.
For mineral oil determination, sample extracts can be directly injected into the on-line liquid-gas chromatography (LC-GC), where a silica column retains fat and polar interferences, and fractionates MOSH and MOAH. As an alternative to the on-line method, MOSH and MOAH can be separated by off-line solid phase extraction (SPE) and then analyzed by GC with flame ionization detector (FID).
Mineral oil extraction can be more or less demanding, depending on the food composition and source of contamination. Overnight extraction with hexane generally allows for the total extraction of mineral oil migrated from the packaging into dry foods such as pasta, but does not allow for the extraction of pre-existing contamination, firmly embedded into the solid structures. A more laborious and solvent consuming procedure has been proposed for the extraction of total contamination from wet-foods and pasta samples.
This PhD work is divided into three main parts. The first one is dedicated to the investigation of the LC-GC system and extraction methods for mineral oil analysis. In particular, an application of a minor technical improvement on the LC-GC method proposed by Biedermann and co-workers is described. It allowed to largely improve the data throughput, to save time and solvent consumption and to increase sensitivity. In particular, a total time and solvent reduction of 34 % and 23 %, respectively, was obtained by speeding up the gas chromatographic run and reducing the liquid chromatographic reconditioning step. The band broadening occurring in the liquid chromatography column during stop flow in the multi-transfer mode was assessed by comparing the variances of the perylene peak width recorded in the stop-flow and normal modes. A band broadening directly proportional to the stop time of LC pumps was observed, however it did not affect the analysis reliability.
In addition, a direct analytical comparison between two popular multidimensional LC-GC systems, namely the Y-interface (retention gap approach) and the syringe-based (programmed temperature vaporizer -PTV- approach) interface is reported. The two LC-GC methods developed were subjected to validation, in terms of linearity over the calibration range, analyte discrimination, precision, accuracy, limits of detection and quantification. Both LC-GC interfaces provided a satisfactory and comparable performance for the determination of MOSH contamination in food products.
The present work also deals with the development/optimization of a comprehensive two-dimensional gas chromatographic method, with dual detection [FID and mass spectrometric (MS)], for the simultaneous identification and quantification of mineral-oil contaminants in a variety of food products. The quantitative results were compared with those obtained by performing a large volume injection, in a GC-FID system, after the same SPE process and by an on-line liquid-gas chromatography method, with very similar results observed. The presence of a series of unknown compounds, that appeared when using the off-line methods, was investigated using the mass spectrometric data, and were tentatively-identified as esterified fatty acids, most probably derived from vegetable oil based inks.
Concerning the extraction approaches, a pressurized liquid extraction (PLE) method has been optimized for rapid mineral oil determination in cardboard and paper samples. The proposed method involves extraction with hexane (2 cycles) at 60 °C for 5 min, and allows for the processing of up to 6 samples in parallel with minimal sample manipulation and solvent consumption. It gave good repeatability (coefficient of variation lower than 5 %) and practically quantitative extraction yield (less than 2 % of the total contamination found in a third separate cycle). The method was applied to different cardboards and paper materials intended for food contact.
Furthermore, two different PLE methods, one for rapid determination of superficial contamination mostly coming from the packaging, the other for efficient extraction of total contamination from different sources, have been developed and optimized. The two methods presented good performance characteristics in terms of repeatability (relative standard deviation lower than 5 %) and recoveries (higher then 96 %). To show their potentiality, the two methods have been applied in combination on semolina pasta and rice packed in direct contact with recycled cardboard.
The second part of this PhD thesis concerns the mineral oil migration into dry semolina and egg pasta packed in recycled and virgin paperboard and in plastic film at room temperature. In particular, migration kinetics has been monitored for up to 2 years, focusing on the influence of time, storage conditions, food packaging material and food characteristics. Mineral oil migration from packaging to food is a rapid phenomenon and reaches considerable levels already after 1 month from packaging time, in particular if recycled paperboard was used. A significant contribution to food contamination coming from packaging can be due to adhesives applied to close the boxes. Not only the packaging, but also the external environment contributed to the total food contamination. Food characteristics seem to influence mineral oil migration from packaging: the egg pasta reached higher levels of contamination than the semolina pasta, due to its higher fat content.
Migration tests were performed also under accelerated conditions (40 and 60 °C for paperboard and plastic film, respectively, up to 30 days) in order to find a correlation with the migration during the shelf-life of the product. The migration kinetic is accelerated with respect to that at room temperature, in particular for the heavier hydrocarbons, but the trend is very similar: the migration of volatile hydrocarbons up to C20 was very fast and complete in a short time.
Finally, the third part of this work is dedicated to the investigation of mineral oil content in human tissues (fat tissue, mesenteric lymph nodes, spleen, liver, lungs, kidneys, heart and brain) focusing on its concentrations and molecular mass distribution. After the development of an appropriate extraction method, mineral oil contents found in human tissues have been correlated with some information on each individual’s physical features and clinical history in order to identify the possible sources of contamination. For a quarter of the subjects (n = 37), a total amount of MOSH above 5g/body was calculated. The composition found in tissues seems determined not so much by the mineral oils the individuals are exposed to, but more so by the selectivity of the uptake, evaporation and metabolic elimination.Per “olio minerale” si intende una complessa miscela di composti ottenuti principalmente dalla distillazione e raffinazione del petrolio, che comprendono idrocarburi saturi (MOSH, mineral oil saturated hydrocarbons) inclusi n-alcani, isoalcani e ciclo alcani (nafteni), e idrocarburi aromatici (MOAH, mineral oil aromatic hydrocarbons) che sono per la maggior parte alchilati. La frazione MOSH può includere anche oligomeri di poliolefine (POSH, polyolefin oligomeric saturated hydrocarbons), che possono migrare da materiali plastici, resine termosaldabili, adesivi e plasticizzanti.
Gli oli minerali presenti negli inchiostri della stampa e nel cartone riciclato sono sufficientemente volatili (< n-C24) da migrare dall’imballaggio all’alimento. L’esposizione agli idrocarburi di origine minerale dovuta agli imballaggi e al cibo rappresenta un pericolo per la salute umana.
Per l’analisi dell’olio minerale, l’estratto ottenuto dal campione in questione può essere direttamente iniettato in un sistema accoppiato LC-GC (liquid-gas chromatography), costituito da una colonna di silice che trattiene il grasso e gli interferenti polari e permette la separazione dei MOSH dai MOAH. In alternativa al metodo on-line, MOSH e MOAH possono essere separati off-line con un’estrazione in fase solida (SPE) e analizzati poi con GC e rivelatore a ionizzazione di fiamma (FID, flame ionization detector).
L’estrazione dell’olio minerale può essere un processo più o meno complicato a seconda della composizione della matrice e della fonte di contaminazione. Generalmente, un’estrazione con esano per una notte permette il recupero totale dell’olio minerale migrato dall’imballaggio in alimenti secchi come la pasta, ma non permette un’estrazione quantitativa di una contaminazione pre-esistente, intrappolata nella matrice. Una procedura più laboriosa è stata proposta per l’estrazione della contaminazione totale di olio minerale da campioni “umidi”.
Questa tesi di dottorato è divisa in tre parti. La prima parte è dedicata ad aspetti analitici e all’estrazione dell’olio minerale. In particolare, viene descritto un miglioramento tecnico, apportato al metodo già proposto da Biedermann e collaboratori, che permette di aumentare la sensibilità, di ridurre il tempo di analisi del 34 % e il consumo di solventi del 23 %, velocizzando la corsa cromatografica e riducendo la fase di ricondizionamento della colonna LC. E’ stato valutato anche l’allargamento della banda nella colonna LC durante l’arresto del flusso (stop-flow) eseguito per trasferire più frazioni al sistema GC con un’unica iniezione. Tale valutazione è stata fatta confrontando la varianza della larghezza del picco del perilene registrato utilizzando lo stop-flow e la modalità normale. L’allargamento di banda è risultato direttamente proporzionale al tempo in cui la pompa LC viene lasciata in stop, e tuttavia tale allargamento non sembra influenzare l’affidabilità dell’analisi.
Inoltre, è stato fatto un confronto tra due sistemi LC-GC con diversi tipi di interfaccia: uno strumento con la Y-interface basata sulla tecnica del retention gap e l’altro con un vaporizzatore a temperatura programmata (PTV, programmed temperature vaporizer). I due diversi metodi sviluppati sono stati sottoposti a validazione in termini di linearità, discriminazione, precisione, accuratezza, limiti di quantificazione e di rilevabilità. Entrambe le interfacce hanno dato risultati soddisfacenti e confrontabili tra loro durante la determinazione di MOSH in prodotti alimentari.
In questo lavoro è riportato anche lo sviluppo/ottimizzazione di una tecnica comprehensive GCxGC con doppio rivelatore (FID e spettrometria di massa) per una simultanea identificazione e quantificazione di olio minerale in prodotti alimentari. I risultati quantitativi sono stati confrontati con quelli ottenuti con analisi in GC-FID, previa separazione di MOSH e MOAH con SPE, e con il metodo on-line LC-GC, ottenendo valori del tutto simili. Con l’utilizzo del metodo off-line SPE-GC-FID si è riscontrata la presenza di composti sconosciuti nel tracciato gas cromatografico, che sono stati poi identificati come esteri degli acidi grassi, molto probabilmente derivanti dall’utilizzo di inchiostri a base di oli vegetali.
Per quanto riguarda le tecniche di estrazione, è stato ottimizzato un metodo PLE (pressurized liquid extraction) per la determinazione dell’olio minerale in campioni di carta e cartone. Il metodo proposto prevede un’estrazione con esano (2 cicli) a 60 °C per 5 minuti e permette di processare sei campioni contemporaneamente con una minima manipolazione del campione e un basso consumo di solvente. Tale metodo presenta una buona ripetibilità (coefficiente di variazione inferiore al 5 %) e un’estrazione praticamente quantitativa (meno del 2 % della contaminazione totale è stata ritrovata in un terzo ciclo separato). Il metodo è stato, quindi, applicato a differenti tipi di cartone e carta utilizzati per il contatto con alimenti.
In aggiunta a ciò, sono stati sviluppati anche due differenti metodi PLE per alimenti secchi con basso contenuto di grasso: uno per la determinazione di olio minerale superficiale, per la maggior parte proveniente da migrazione da imballaggio, e l’altro per l’estrazione della contaminazione totale proveniente da differenti fonti. I due metodi presentano una buona ripetibilità (deviazione standard inferiore al 5 %) e ottimi recuperi (oltre il 96 %). Per sottolineare la potenzialità di questi metodi, essi sono stati applicati in combinazione su campioni di riso e di pasta di semola tenuti a contatto diretto con cartone riciclato.
La seconda parte di questa tesi riguarda la migrazione di olio minerale in pasta secca (di semola e all’uovo) confezionata in imballaggi di cartone riciclato, in fibra vergine e in pacchi di film plastico, tenuti a temperatura ambiente. In particolare, le cinetiche di migrazione sono state monitorate nell’arco di due anni, focalizzando l’attenzione sull’influenza del tempo, delle condizioni di stoccaggio, sul materiale dell’imballaggio e sulle caratteristiche dell’alimento. La migrazione dell’olio minerale dall’imballaggi all’alimento è un processo rapido che può raggiungere considerevoli livelli di contaminazione già dopo un mese dal momento del confezionamento, soprattutto se viene utilizzato il cartone riciclato. La presenza di colla utilizzata per la chiusura delle confezioni sembra contribuire in modo significativo alla contaminazione totale dell’alimento confezionato. Non solo l’imballaggio, ma anche l’ambiente di stoccaggio circostante al campione incide sulla contaminazione totale dell’alimento. La quantità di grasso dell’alimento, inoltre, influenza la migrazione dell’olio minerale dall’imballaggio.
Sono stati eseguiti anche test di migrazione accelerata a temperature di 40 °C per imballaggi di cartone e 60 °C per i pacchi in film plastico, della durata di 30 giorni, per cercare una correlazione con la migrazione durante la shelf-life del prodotto. Le cinetiche di migrazione sono ovviamente accelerate rispetto a quelle ottenute a temperatura ambiente, soprattutto per gli idrocarburi a più alto peso molecolare. In generale, però, l’andamento rimane simile, con una migrazione degli idrocarburi fino al n-C20 molto rapida e completa in poco tempo.
Infine, la terza parte di questa tesi è dedicata all’indagine del contenuto di olio minerale in tessuti umani (tessuto adiposo, linfonodi mesenterici, milza, fegato, polmoni, reni, cervello e cuore) focalizzando l’attenzione sulla sua concentrazione e distribuzione dei pesi molecolari. In seguito allo sviluppo di un appropriato metodo di estrazione, il contenuto di olio minerale ritrovato nei vari tessuti umani è stato correlato con informazioni personali e cliniche dell’individuo a cui appartenevano, allo scopo di identificare una possibile fonte di contaminazione. Per un quarto dei soggetti analizzati (n = 37), sono stati trovati livelli di MOSH maggiori a 5 g per persona. La composizione della contaminazione ritrovata nei tessuti umani sembra determinata non tanto dall’olio minerale a cui gli individui sono stati esposti, quanto dalla selettività dovuta a processi metabolici
A study on different storage conditions affecting mineral oils migration from packaging to semolina and egg pasta
No full textMost foodstuffs are provided with a packaging which carries
out several important functions. However, the transfer of
undesirable compounds can occur during the shelf-life of the
product. In particular, cardboard packaging represents an
important source of food contamination with mineral oil,
when recycled fibers or mineral oil based printing inks are
used. In this work MOSH (mineral oil saturated
hydrocarbons), MOAH (mineral oil aromatic hydrocarbons),
POSH (polyolefin oligomeric saturated hydrocarbons), and
DIPN (diisopropyl naphtalenes) migration from packaging to
dry foods has been monitored up to 1 year, focusing on the
influence of food packaging material, fat content of the food,
time and storage condition. Furthermore, contribution of hot
melt adhesives used to close boxes to the total
contamination was also evaluated. Semolina and egg pasta,
of the same small size, were packed in plastic film bags and
in recycled and virgin paperboard boxes and stored under
two different conditions at ambient temperature. Same
samples were stored on shelves to simulate the real
common storage conditions, while others were wrapped in
aluminum in order to force the migration only towards pasta,
excluding any external influence. The mineral oil migration
from a transport box consisting of corrugated board, through
the primary packaging, was also evaluated. Migration
behavior was studied measuring both the mineral oil amount
lost by the packaging (calculated as the difference between
pre- and post-contact contamination) and the mineral oil
amount migrated in pasta samples after the exposure
(subtracted from the pasta contamination at time zero).
Diffusion of migrated mineral oil inside the product was also
monitored by applying selective extraction methods (for
semolina pasta). A POSH contamination was evident in
pasta samples stored in plastic film. Very low contamination
levels (< 0.6 mg/kg of MOSH) were found in pasta sample
packaged in virgin paper. An important contribution due to
the use of hot melt adhesives was evidenced. Higher
contamination levels (about 5 and 12 mg/kg of MOSH for
semolina and egg pasta, respectively) were found in pasta
packaged in recycled paperboard for 1 year. Samples
reached a steady contamination level, already after the first
1–3 months of storage, corresponding to about 20 and 50%
of potential migration for semolina and egg pasta,
respectively. The contribution of the external ambient was
well evident in samples stored on the shelves (especially for
egg pasta), while a little contribution due to the corrugated
cardboard used as secondary packaging was observed
Coupled LC-GC determination of mineral oil saturated hydrocarbons in vegetable oils from the italian market
No full textFood Packaging Contaminants with a Special Focus on Hydrocarbon Contaminants and Nanoparticles
No full textFood can be contaminated with a wide class of chemicals, including both organic and inorganic compounds also in the form of nanoparticles. Food packaging contaminants can originate either from the food packaging itself or from adhesives and printing inks. Among potential migrants, mineral oil hydrocarbons have gained increasing interest in the past decade, along with resin oligomeric hydrocarbons mainly from hot melt adhesives, polyolefin oligomeric hydrocarbons from polyolefin plastic materials and sealing layer, and nanoform migrants. Because of their negative impact on human health, the release of chemicals from food packaging has raised health and regulatory concerns
Determination of hydrocarbon contamination in foods. A review.
No full textHydrocarbon contaminants in foods can be grouped into two main classes, based on the main process involved in their formation. The first class of contaminants is represented by mineral oil hydrocarbons, which include both saturated and aromatic hydrocarbons (mainly alkylated), originating from petrogenic processes. The other class of compounds originates from incomplete pyrogenic processes and comprises parent polycyclic aromatic hydrocarbons with 2-6 rings. The contamination with these compounds can occur at any stage of food production, namely from field environmental contamination, farming practices, food transformation processes (industrial and domestic), and migration from packaging materials. Although these contaminants are very similar from a chemical point of view and as far as some analytical issues are concerned, sample preparation and the final analytical determination applied are very specific. In this review the two classes of contaminants will be discussed separately, considering not only the analytical approach but also their source of contamination, toxicity and legislation issues
Microwaved assisted extraction (MAE) and microwave assisted saponification (MAS) followed by on-line LC-GC for efficient and rapid mineral oil extraction and analysis in different food matrices (poster)
No full textMineral oil saturated hydrocarbon (MOSH) and mineral oil aromatic hydrocarbon (MOAH) determination in vegetable oils and fats
No full textMineral oils are complex mixtures of saturated (MOSH) and aromatic hydrocarbons (MOAH), mainly alkylated, giving gas chromatographic (GC) traces characterized by the presence of hundreds of unresolved peaks forming one or more "humps" with different molecular weight distribution, depending on the source of contamination. Various foods can be contaminated with mineral oils. Different sources of contamination have been recognized for vegetable oils: environmental contamination, use of lubricating in the extraction plant, storage and transport of he raw matter in jute bags, transport of the oil in ships previously used to transport mineral oils etc.
It is well known that vegetable oils can be contaminated with mineral oils, but almost all published data refers to the analysis of the saturated fraction (MOSH), without checking for the presence of the MOAH. Since MOSH and MOAH have different toxicological relevance, and particularly MOAH are suspected to contain carcinogenic compounds, it is important to quantify them separately.
Recently, both on-line liquid chromatography (LC)-GC flame ionization detection (FID) and off-line solid phase extraction (SPE)-GC-FID approaches have been proposed for MOSH and MOAH determination. A comparison between off-line and on-line approaches for the assessment of these contaminants in vegetable oil and fats is presented and discussed. Sample pre treatment and enrichment is important for accurate determination of the contamination and to reach the required sensitivity when analyzing vegetable oils and fats. The possibility to use alternative approaches such as automated solid phase extraction and micro scale saponification for sample enrichment and purification have been explored. Data on MOSH and MOAH content in a number of samples are reported and discussed. Unambiguous presence of mineral oils in contaminated samples has been confirmed through GC-MS analysis of hopanes (recognized markers for confirming the presence of mineral oil
Rapid off-line SPE-GC-FID determination of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) using different large volume injection techniques and comparison with the on-line LC-GC technique
No full textRapid SPE-GC-FID Determination of MOSH (Mineral Oil Saturated Hydrocarbons) and MOAH (Mineral Oil Aromatic Hydrocarbons) in Printing Inks, Recycled Cardboard and in Dried Food as a Consequence of Migration Under Accelerated Test Condition (oral presentation)
No full textpeer reviewe
Migration of selected hydrocarbon contaminants into dry pasta packaged in direct contact with recycled paperboard
No full textThis paper deals with the migration of selected hydrocarbon contaminants, namely mineral oil hydrocarbons (MOH), diisopropyl naphthalenes (DIPN) and polyalphaolefins (PAO) from adhesives into dry semolina and egg pasta packaged in direct contact with recycled paperboard. Migration was monitored during its shelf life (for up to two years) simulating storage in a supermarket (packs on shelves) and conditions preventing exchange with the surrounding environment (packs wrapped in aluminium foil). Migration from the secondary packaging (transport boxes of corrugated board) was also studied for semolina pasta. After 24 months of exposure, semolina pasta stored on shelves reached 3.2 and 0.6 mg kg(-1) of MOSH and MOAH, respectively, Migration from the adhesives used to close the boxes and from the transport boxes contributed about 30% and 25% of the total contamination, respectively. The highest contamination levels (14.5 and 2.0 mg kg(-1) of MOSH and MOAH, respectively, after 24 months) were found in egg pasta stored on shelves (no adhesives), and seemed due to the highest contribution from the external environment
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