Exposure to phthalic acid, phthalate diesters and phthalate monoesters from foodstuffs: UK total diet study results.

Phthalates are ubiquitous in the environment and thus exposure to these compounds can occur in various forms. Foods are one source of such exposure. There are only a limited number of studies that describe the levels of phthalates (diesters, monoesters and phthalic acid) in foods and assess the exposure from this source. In this study the levels of selected phthalate diesters, phthalate monoesters and phthalic acid in total diet study (TDS) samples are determined and the resulting exposure estimated. The methodology for the determination of phthalic acid and nine phthalate monoesters (mono-isopropyl phthalate, mono-n-butyl phthalate, mono-isobutyl phthalate, mono-benzyl phthalate, mono-cyclohexyl phthalate, mono-n-pentyl phthalate, mono-(2-ethylhexyl) phthalate, mono-n-octyl phthalate and mono-isononyl phthalate) in foods is described. In this method phthalate monoesters and phthalic acid are extracted from the foodstuffs with a mixture of acidified acetonitrile and dichloromethane. The method uses isotope-labelled phthalic acid and phthalate monoester internal standards and is appropriate for quantitative determination in the concentration range of 5-100 µg kg⁻¹. The method was validated in-house and its broad applicability demonstrated by the analysis of high-fat, high-carbohydrate and high-protein foodstuffs as well as combinations of all three major food constituents. The methodology used for 15 major phthalate diesters has been reported elsewhere. Phthalic acid was the most prevalent phthalate, being detected in 17 food groups. The highest concentration measured was di-(2-ethylhexyl) phthalate in fish (789 µg kg⁻¹). Low levels of mono-n-butyl phthalate and mono-(2-ethylhexyl) phthalate were detected in several of the TDS animal-based food groups and the highest concentrations measured corresponded with the most abundant diesters (di-n-butyl phthalate and di-(2-ethylhexyl) phthalate). The UK Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) considered the levels found and concluded that they did not indicate a risk to human health from dietary exposure alone.

Environmental fate of processed natural rubber latex.

In this study, processed natural rubber latex was degraded in outdoor aquatic microcosms, under a number of treatment scenarios for 200 days. The analytical strategy adopted aimed to characterise a range of volatile, semi-volatile and non-volatile substances. Zinc, was shown to migrate from the latex into solution and increase in concentration over time. Dissolved compounds for which predicted formulas were generated largely consisted of oxygen containing compounds, and are potential oxidised polyisoprene oligomers of various chain lengths. A classification of samples based on principal component analysis showed a clear separation of the degraded latex samples from the representative controls. This technique identified an increase in the complexity of the substances produced and showed that these substances undergo further degradation and transformation processes. A number of volatile substances were also identified indicating the atmosphere to be a potential receiving environmental compartment for polymer degradates. Overall, the results show that complex mixtures of substances are produced when polymer-based materials degrade under environmental conditions.

Determination of phthalate diesters in foods.

Methodology for the determination of 15 phthalate diesters (dimethyl phthalate, diethyl phthalate, diisopropyl phthalate, diallyl phthalate, diisobutyl phthalate, di-n-butyl phthalate, di-n-pentyl phthalate, di-n-hexyl phthalate, benzyl butyl phthalate, dicyclohexyl phthalate, di-(2-ethylhexyl) phthalate, di-n-octyl phthalate, diisononyl phthalate, diisodecyl phthalate, and di-n-decyl phthalate) is described. The method was validated in-house and its broad applicability demonstrated by the analysis of high-fat, high-carbohydrate and high-protein foodstuffs as well as combinations of all three major food constituents. Following on from the analysis of the 20 UK Total Diet Study samples, 261 foodstuffs were purchased and tested for their phthalate levels. Phthalate diesters were confirmed to be present in 77 samples. Di-(2-ethylhexyl) phthalate was the most frequently detected (66 samples), although the highest levels found were for the isomeric mixture diisononyl phthalate. Additional studies confirmed that, for some foodstuffs, packaging materials did contribute to the phthalate diester concentration in the foodstuff and one example is presented.

Effects of environmental conditions on latex degradation in aquatic systems.

Following use polymer materials may be released to the natural environment distributed to various environmental compartments and may undergo a variety of mechanical and chemical weathering processes. This study characterised the degradation of a latex polymer of different thicknesses under a range of environmental conditions in outdoor microcosms. Samples were immersed in either demineralised water, artificial freshwater and marine water media and exposed for a period of 200-250 days with exposure starting at different times of the year. Effects of pH, agitation and the exclusion of light on degradation were also studied. At the end of the exposure period, recovery of polymer material ≥ 1.6 µm ranged from a low of 22.04% (± 16.35, for the freshwater treatment at pH5.5) to a high of 97.73% (± 0.38, for the exclusion of light treatment). The disappearance of the bulk material corresponded to an increase in nanoparticles and dissolved organic material in the test media. Modelled degradation kinetics were characterised by multi-phasic degradation patterns and the results indicated degradation rate is affected by light intensity and polymer thickness. Mass balance analysis indicates that losses of volatile materials to the air compartment may also be occurring.

Volatile fingerprints of seeds of four species indicate the involvement of alcoholic fermentation, lipid peroxidation, and Maillard reactions in seed deterioration during ageing and desiccation stress.

The volatile compounds released by orthodox (desiccation-tolerant) seeds during ageing can be analysed using gas chromatography-mass spectrometry (GC-MS). Comparison of three legume species (Pisum sativum, Lathyrus pratensis, and Cytisus scoparius) during artificial ageing at 60% relative humidity and 50 °C revealed variation in the seed volatile fingerprint between species, although in all species the overall volatile concentration increased with storage period, and changes could be detected prior to the onset of viability loss. The volatile compounds are proposed to derive from three main sources: alcoholic fermentation, lipid peroxidation, and Maillard reactions. Lipid peroxidation was confirmed in P. sativum seeds through analysis of malondialdehyde and 4-hydroxynonenal. Volatile production by ageing orthodox seeds was compared with that of recalcitrant (desiccation-sensitive) seeds of Quercus robur during desiccation. Many of the volatiles were common to both ageing orthodox seeds and desiccating recalcitrant seeds, with alcoholic fermentation forming the major source of volatiles. Finally, comparison was made between two methods of analysis; the first used a Tenax adsorbent to trap volatiles, whilst the second used solid phase microextraction to extract volatiles from the headspace of vials containing powdered seeds. Solid phase microextraction was found to be more sensitive, detecting a far greater number of compounds. Seed volatile analysis provides a non-invasive means of characterizing the processes involved in seed deterioration, and potentially identifying volatile marker compounds for the diagnosis of seed viability loss.

Identification of unknown migrants from food contact materials.

Materials that come into contact with foodstuffs can transfer components that may cause odour or taint problems or in the worse case cause the foodstuff to be unsafe to eat. The identities of some of these are easily predicted from the chemistry of known components but others are not. In this respect, it is important to be able to identify and quantify these chemicals. This chapter describes the need for methods of identification of unknown chemicals that may migrate. Mass spectrometric analytical methods are described, including headspace-gas chromatography with mass spectrometry (HS-GC-MS), liquid injection gas chromatography with MS, and liquid chromatography with time-of-flight MS (LC-TOF-MS).

Analysis of reaction products of food contaminants and ingredients: bisphenol A diglycidyl ether (BADGE) in canned foods.

Bisphenol A diglycidyl ether (BADGE) is an epoxide that is used as a starting substance in the manufacture of can coatings for food-contact applications. Following migration from the can coating into food, BADGE levels decay and new reaction products are formed by reaction with food ingredients. The significant decay of BADGE was demonstrated by liquid chromatographic (LC) analysis of foodstuffs, that is, tuna, apple puree, and beer, spiked with BADGE before processing and storage. Life-science inspired analytical approaches were successfully applied to study the reactions of BADGE with food ingredients, for example, amino acids and sugars. An improved mass balance of BADGE was achieved by selective detection of reaction products of BADGE with low molecular weight food components, using a successful combination of stable isotopes of BADGE and analysis by LC coupled to fluorescence detection (FLD) and high-resolution mass spectrometric (MS) detection. Furthermore, proteomics approaches showed that BADGE also reacts with peptides (from protein digests in model systems) and with proteins in foods. The predominant reaction center for amino acids, peptides, and proteins was cysteine.

A method of test for residual isophorone diisocyanate trimer in new polyester-polyurethane coatings on light metal packaging using liquid chromatography with tandem mass spectrometric detection.

A method of test for residual isophorone diisocyanate (IPDI) trimer in experimental formulation polyester-polyurethane (PEPU) thermoset coatings on metal food packaging is described. The method involves extraction of coated panels using acetonitrile containing dibutylamine for concurrent derivatisation, and then high performance liquid chromatography with electrospray ionisation tandem mass spectrometric detection (LC-MS/MS). Single laboratory validation was carried out using three different experimental PEPU-based coatings. The calibrations were linear, the analytical recovery was good, no interferences were seen, and substance identification criteria were met. The detection limit of the method is around 0.02 micro g/100 cm(2) of coating, which for a typical sized can and assuming complete migration of any residual IPDI trimer, corresponds to about 0.2 micro g/kg food or beverage. Separate studies indicated that, even if migration occurred at such low levels, the IPDI trimer would not be expected to persist in canned aqueous or fatty foodstuffs as it would hydrolyse to the corresponding aliphatic amine or react with food components to destroy the isocyanate moiety. The method of test developed here for residual IPDI trimer in thermoset polyester-polyurethane coatings should prove to be a valuable tool for investigating the cure kinetics of these novel coatings and help to guide the development of enhanced formulations.