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.

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.

Analytical approaches to identify potential migrants in polyester-polyurethane can coatings.

The safety of a polyester-polyurethane can coating has been assessed using a suite of complementary analytical methods to identify and estimate the concentrations of potential chemical migrants. The polyester was based on phthalic acids and aliphatic diols. The polyisocyanate cross-linking agent was 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl cyclohexane homopolymer (IPDI) blocked with methylethylketone oxime (MEKO) to make a one-part formulation. The overall migrate, obtained using solvent extraction of cured films, comprised almost completely of 12 cyclic and one linear polyester oligomer up to molecular weight 800 and containing up to six monomer units. These 13 oligomers covered a total of 28 isomeric forms. Other minor components detected were plasticisers and surfactants as well as impurities present in the starting materials. There was no detectable residue of either the blocked isocyanate (<0.01 microg/dm(2)) used as the starting substance or the unblocked isocyanate (<0.02 microg/dm(2)). The level of extractable IPDI was used as an indicator of the completeness of cure in experimental coatings. These studies revealed that there was an influence of time, temperature and catalyst content. Polymerisation was also influenced by the additives used and by the ageing of the wet coating formulation over several months. These studies allow parameters to be specified to ensure that commercial production coatings receive a full cure giving low migration characteristics.

Determination of brominated flame retardants in food by LC-MS/MS: diastereoisomer-specific hexabromocyclododecane and tetrabromobisphenol A.

The levels of the brominated flame retardants (BFRs) hexabromocyclododecane (alpha, beta and gammaHBCD diastereoisomers) and tetrabromobisphenol A (TBBPA) have been determined in two studies using LC-MS/MS. The methodology developed was validated in-house and used to analyse UK 2004 Total Diet Study (TDS) samples and shellfish (oysters, mussels and scallops) collected from Scotland. HBCD was detected in most samples; in both studies the alphaHBCD diastereoisomer was generally the most abundant as opposed to the gamma diastereoisomer that tends to dominate in environmental samples and manufactured products. It is reported that selective metabolism or biotransformation of the beta and gamma diastereoisomers may be taking place. TBBPA was not detected in any samples above the limit of detection, which was as low as 0.05 microg kg(-1). This may be because TBBPA, unlike HBCD, is chemically bound to the polymer matrix during manufacture and not readily leached. The UK Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) concluded that the concentrations of HBCD and TBBPA detected in the TDS study did not raise toxicological concerns and, as levels in the shellfish samples were in a similar concentration range, it was concluded that exposure to the BFRs measured is not significant when compared to exposure from the rest of the diet.