Flake formation and composition in soda-lime-silica and borosilicate glasses.

Glass is a food contact material that has been used for a long time in food packaging because it is chemically durable and stable. However, when used for a long time in an aqueous solution or under certain conditions in which alteration may occur, solid flakes may be formed. The phenomenon could be observed when the process of boiling water in a glass kettle is repeated. Transparent and shiny needle-shaped glass fragments appear floating in the water, which may cause complaints from consumers. The purpose of this study is to investigate the conditions leading to the formation of flakes and to identify the components of the suspended flakes in glass container. In this study we investigated the formation of flakes at different temperatures (70-100 °C), initial pH values (3-11) and varying the solution composition (with Na+, K+, Ca2+, Mg2+ concentrations from 0.2 to 40 mg/L). Two types of glass materials, soda-lime-silica glass and borosilicate glass (heat-resistance glass) were examined. Results show that flakes were observed under the following conditions: 24 h at more than 90 °C, pH 8, and 20 mg/L Ca2+ for soda-lime-silica glass and more than 100 °C, pH 11 for borosilicate glass. The component of flakes was identified as a mixture of hydrates of magnesium, calcium, and aluminum silicate analyzed by X-ray fluorescence spectroscopy, inductively coupled plasma-optical emission spectroscopy, and X-ray diffraction.

Analysis of N-nitrosamines and N-nitrosatable substances from baby bottle rubber teats by liquid chromatography tandem mass spectrometry.

A simple and sensitive method based on liquid chromatography-atmospheric pressure chemical ionisation-tandem mass spectrometry (LC-APCI-MS/MS) was developed and validated to determine the levels of 13N-nitrosamines and N-nitrosatable substances migrated from rubber teats into artificial saliva. The migration test from rubber teats was conducted at 40 °C and for 24 h in artificial saliva, and the migrated artificial saliva solution was analysed by liquid chromatography tandem mass spectrometry (LC-MS/MS) without further extracting steps. The sensitivity of N-nitrosamines was examined by applying atmospheric chemical ionisation and electrospray ionisation to optimise the mass spectrometric conditions, and the atmospheric chemical ionisation (APCI) mode exhibited 1.6-19 times higher sensitivity. Method validation showed acceptable linearity, precision, and accuracy, and the detection and quantification limits were 0.07-0.35 and 0.24-1.1 µg kg-1, respectively. The developed liquid chromatography-atmospheric chemical ionisation-tandem mass spectrometry method was applied to 39 domestic and imported rubber teats. From 39 samples, N-nitrosamines [N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMOR), and N-nitroso n-methyl N-phenylamine (NMPhA)] were detected in 30 samples, with N-nitrosatable substances in 17 samples give rise to NDMA, NMOR, and N-nitrosodiethylamine. However, the levels were below the specific migration limit of Korean Standards and Specifications for Food Containers, Utensils, and Packages and EC Directive 93/11/EEC.

LC-MS/MS analysis of BADGE, NOGEs, and their derivatives migrated from food and beverage metal cans.

A simple and novel method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated to determine the levels of 10 compounds (bisphenol A diglycidyl ether (BADGE), novolac-glycidyl ethers (NOGEs), and their related compounds) migrated from food and beverage cans into food simulants. Method validation showed acceptable linearity, precision, and accuracy. The detection limits ranged from 0.28 to 14.8 µg L-1, and the quantification limits ranged from 0.94 to 49.3 µg L-1. Water, 4% acetic acid, 50% ethanol, and n-heptane were employed as food simulants for the migration tests, and the developed LC-MS/MS method was applied to 104 epoxy-coated beverage and food metal cans. Only BADGE∙2H2O and BADGE were detected; the levels were below the specific migration limit. Based on the obtained migration results, the estimated daily intakes (EDIs) of BADGE∙2H2O and BADGE were calculated. Exposure assessments were conducted to compare the EDI with the tolerable daily intake (TDI), with a relatively low percentage of the TDI being reported. NOGE and its related compounds were not detected in the monitored cans. Long-term storage tests were also conducted at 60°C over 30 days. Only BADGE∙2H2O was detected in all food simulants, except for n-heptane, and the maximum amount detected was 114.6 µg L-1 in 50% ethanol.

HS-GC/MS method development and exposure assessment of volatile organic compounds from food packaging into food simulants.

A simultaneous headspace-gas chromatography/mass spectrometry (HS-GC/MS) method was developed and validated to determine the migration of 12 volatile organic compounds (methanol, acetone, methylethylketone, ethylacetate, isopropylalcohol, benzene, toluene, ethylbenzene, xylene, cumene, propylbenzene, and styrene) from food contact materials into food simulants (water, 4% acetic acid, 50% ethanol, and n-heptane). The limits of detection and quantification were 0.007-0.201 mg L-1 and 0.023-0.668 mg L-1, respectively. The method was applied to 205 samples of paper/paperboard, polyethylene, polypropylene, polystyrene, and polyethylene terephthalate. The estimated daily intake (EDI) was calculated using the migration results. Exposure assessments were carried out to compare the EDI to the tolerable daily intake (TDI); the results indicated that the EDI of styrene represented only a small percentage (8.0%) of the TDI. This analytical method will be a useful tool to examine levels of various volatile compounds migrating from food packaging to food simulants using HS-GC/MS method.