On-line steam distillation/purge and trap analysis of halogenated, nonpolar, volatile contaminants in foods.

An on-line, steam distillation/purge and trap gas chromatographic procedure is described for determination of halogenated analytes in foods and beverages. Recoveries were generally >80% (versus aqueous standards) from vegetable oil, flour, root beer, cream (10% butter fat), and milk spiked at 1-3 micrograms/kg for each of the 32 analytes studied. Analytes ranged in volatility from vinyl chloride to 1,2,3,4-tetrachlorobenzene. Repeatabilities from aqueous standards were <10% for most analytes. For a 1 g food sample, method detection limits ranged from 0.02 to 0.2 micrograms/kg for the 32 analytes. Reduced recoveries for less volatile analytes, however, occurred when steam-distillable, nonpolar food components were carried to the sparger. This effect was observed for citrus beverages containing steam-volatile limonene, roasted and ground coffees, and some salad dressings. The method was applied to a variety of foods.

The occurrence of phthalate ester and di-2-ethylhexyl adipate plasticizers in Canadian packaging and food sampled in 1985-1989: a survey.

Selected foods (260 samples) packaged in materials with the potential to contribute plasticizers to the food, and available food composites (98 samples) obtained from the Canadian Health Protection Branch Total Diet Program, were analysed for phthalate plasticizers and di-2-ethylhexyl adipate (DEHA). The available contacting packaging was also analysed for plasticizers. The results show DEHA in food-contacting film and as a migrant in store-wrapped meat, poultry, fish, cheese and ready-to-eat foods at levels as high as 310 micrograms/g (cheese). DEHA levels in unheated film-wrapped ready-to-eat foods were increased by heating. The di-2-ethylhexyl, dibutyl, butylbenzyl and diethyl phthalate esters (DEHP, DBP, BBP and DEP, respectively) were also found in both the packaging and the contacted foods. Low levels of DEHP (0.065 micrograms/g, average in beverages and 0.29 micrograms/g, average in foods) associated with the use of DEHP-plasticized cap or lid seals, were found in a variety of glass-packaged foods; DBP, BBP and DEHP were found, as previously described, in butter and margarine as migrants from the aluminium foil-paper laminates; and DEP in pies at 1.8 micrograms/g (average) as a migrant from the pie carton windows. In most cases, plasticizers detected in the food were also found in the associated packaging. When possible, 'core' or non-contacting food portions were analysed to verify the migration phenomena.

Survey of arsenic in total diet food composites and estimation of the dietary intake of arsenic by Canadian adults and children.

During a comprehensive total diet study extending from 1985 to 1988, foods were collected in 6 Canadian cities (in one of them, a pilot study was conducted twice). For each of the 7 collections, foods were processed into 112 composites (105 in the initial pilot trial). Total arsenic was determined in all samples. The mean, median, and range of arsenic concentrations in all samples were 73.2, 5.1, and < 0.1-4830 ng/g, respectively. Food groups containing the highest mean arsenic levels were fish (1662 ng/g), meat and poultry (24.3 ng/g), bakery goods and cereals (24.5 ng/g), and fats and oils (19.0 ng/g). The estimated daily dietary ingestion of total arsenic by the average Canadian was 38.1 micrograms and varied from 14.9 micrograms for the 1- to 4-year-old group to 59.2 micrograms for 20- to 39-year-old males.

Studies into the transfer and migration of phthalate esters from aluminium foil-paper laminates to butter and margarine.

Retail samples of Canadian butter and margarine wrapped in aluminium foil-paper laminate were found to contain dibutyl, butyl benzyl and/or di-2-ethylhexyl phthalate (DBP, BBP, DEHP) as packaging migrants at levels up to 10.6, 47.8 and 11.9 micrograms/g, respectively. These phthalates were determined by capillary gas chromatography with flame ionization detection (GC-FID) after clean-up of the separated oil by sweep co-distillation. The phthalate esters found in the contacted butter or margarine were also found in the contacting wrappers. They were determined in wrapper extracts by liquid chromatography with diode array detection or by GC-FID. Analysis of unused wrappers showed 76-88% of the total DBP and DEHP to be present on the foil (outer) surface as a component of the protective coating (washcoat). The remainder of the DBP and DEHP was found on the food-contacting paper surface, presumably by transfer from the outer to inner surface during storage in tightly wound rolls, although transfer of phthalate esters, if present in the paper-foil adhesive, cannot be ruled out. Food-contacting surface concentrations of DBP and DEHP were found to be 2.4 to 4.7 and 2.8 to 3.6 micrograms/cm2, respectively. Samples of each packaging component: paper, foil, adhesive, washcoat and inks were analysed for phthalate esters and only the washcoat was found to contain phthalate esters.

Total arsenic in foods after sequential wet digestion, dry ashing, coprecipitation with ammonium pyrrolidine dithiocarbamate, and graphite-furnace atomic absorption spectrometry.

A graphite-furnace atomic absorption (GFAAS) method is described for determining total arsenic (organic and inorganic compounds) in foods. Samples ranging from 1 to 40 g (depending on moisture content) were digested with HNO3 and dry-ashed at 500 degrees C overnight after addition of MgO. After dissolution in HCl, the arsenic was reduced with iodide and ascorbic acid and precipitated with ammonium pyrrolidine dithiocarbamate (APDC) in the presence of nickel carrier. Precipitates were collected on 0.3 micron cellulose acetate filters and dissolved in 10% HNO3 containing modifier. Ba(NO3)2 was added to remove a sulfate interference resulting from decomposition of APDC. Arsenic was determined using GFAAS. Accuracy of the method was good for 7 U.S. National Bureau of Standards (NBS) Standard Reference Materials and 3 National Research Council of Canada (NRCC) round-robin samples. Recovery of arsenic(V) from foods averaged 99.2% for peak heights and 97.1% for peak areas, with relative standard deviations (RSD) of 2.2% for peak heights and 3.3% for peak areas for all NBS and NRCC materials. Detection limit of the method was ca 10 ng arsenic.

Dietary intakes of lead, cadmium, arsenic and fluoride by Canadian adults: a 24-hour duplicate diet study.

Twenty-four hour duplicate diets, including drinking water and snacks, were collected from 24 adults living in five Canadian cities. Each diet was separated by the participants into 10 food categories, and each of the samples was analyzed in duplicate for lead, cadmium, arsenic and fluoride. Minimum detection limits for the respective elements in foods were about 0.1, 0.01, 0.3 and 5 ng/g. Mean dietary intakes were 53.8 micrograms/day or 0.80 micrograms/kg/day for lead, 13.8 micrograms/day or 0.21 micrograms/kg/day for cadmium, and 16.7 micrograms/day or 0.26 micrograms/kg/day for arsenic. The median intakes were 42.7 micrograms/day or 0.57 mu/kg/day for lead, 11.9 micrograms/day or 0.17 micrograms/kg/day for cadmium, and 9.79 micrograms/day or 0.139 micrograms/kg/day for arsenic. Half of the participants lived in communities with 1 microgram/g fluoride in the drinking water, and half lived in cities with less than 0.2 microgram/g fluoride in the water. The dietary intake of fluoride for the former was 2802 micrograms/day or 39.7 micrograms/kg/day; while that of the latter was 563 micrograms/day or 8.5 micrograms/kg/day. The respective median intakes of fluoride were 2090 micrograms/day or 30.3 micrograms/kg/day, and 414 micrograms/day or 7.0 micrograms/kg/day. Contribution of individual foods and food categories to the dietary intakes is discussed.