Additive migration from plastics into foods : a guide for analytical chemists

Preface....................................................................................................................1 1 Additive Migration from Plastics into Packaged Commodities.........................5 1.1 Introduction...........................................................................................5 1.2 Principles of Extractability Testing..........................................................5 1.3 Extractability Testing in the European Union.........................................7 1.4 Extractability Testing in the UK..............................................................8 1.5 Extractability Testing in the USA............................................................8 2 Types of Polymers Used in Commodity Packaging.........................................13 2.1 Polyolefins and Copolymers..................................................................13 2.1.1 Polyethylene.............................................................................13 2.1.2 Polyethylene Naphthalate........................................................15 2.1.3 Polyethylene co-methacrylic Acid.............................................15 2.1.4 Polypropylene..........................................................................15 2.2 Polymethyl Pentene...............................................................................16 2.3 Ethylene-vinyl Acetate Copolymers......................................................16 2.4 Ionomers..............................................................................................16 2.5 Vinyl Plastics and Vinyl Copolymers....................................................17 2.5.1 Polyvinyl Acetate.....................................................................18 2.6 Polystyrene and its Copolymers............................................................18 2.7 Polyacrylonitrile...................................................................................19 2.8 Acrylic-based Multi Polymer Compounds............................................19 3 Non-Polymeric Components of Plastics..........................................................27 3.1 Polymerisation Residues.......................................................................29 3.2 Residual and Unreacted Starting Materials...........................................29 3.3 Polymerisation Medium........................................................................30 3.4 Catalyst Decomposition Agents............................................................31 3.5 Other Impurities Introduced During Polymerisation.............................31 3.5.1 Chemicals Added During Polymerisation.................................31 3.6 Processing Aids.....................................................................................31 3.6.1 Antiblock Agents.....................................................................32 3.6.2 Antioxidants............................................................................32 3.6.3 Antisplit Agents.......................................................................32 3.6.4 Antistatic Agents......................................................................32 3.6.5 Heat Stabilisers........................................................................33 3.6.6 Lubricants................................................................................33 3.6.7 Melt Strength Improvers..........................................................34 3.6.8 Mould Release Agents..............................................................34 3.6.9 Plasticisers................................................................................34 3.6.10 Slip Additives...........................................................................35 3.6.11 Other Stabilisers.......................................................................35 3.7 End-Use Additives................................................................................35 3.7.1 Antiblock Additives.................................................................36 3.7.2 Antifungal agents.....................................................................36 3.7.3 Antioxidants............................................................................36 3.7.4 Antistatic Agents......................................................................36 3.7.5 Bactericidal Agents...................................................................36 3.7.6 Brighteners and Whiteners.......................................................36 3.7.7 Colorants.................................................................................37 3.7.8 Expanding Agents (Blowing Agents, Foaming Agents).............37 3.7.9 Impact Improvers.....................................................................38 3.7.10 Lubricants................................................................................38 6.2 Phthalates and Adipates in Aqueous and Fatty Extractants..................94 7 Determination of Organotin Thermal Stabilisers in Extractants...................105 7.1 Organotin Compounds in Fatty Extractants.......................................105 8 Determination of Organic Sulfur Compounds in Extractants.......................109 9 Determination of Polydimethyl Siloxanes in Extractants..............................119 9.1 Wine and Olive Oil.............................................................................119 9.1.1 PDMS in Olive Oil and Wine.................................................120 10 Determination of Lubricants in Extraction Liquids......................................125 11 Determination of Monomers and Oligomers in Extractants.........................129 11.1 Determination of Acrylonitrile in Aqueous and Fatty (Liquid Paraffin) Extractants..............................................................129 11.1.1 Determination of Acrylonitrile in Aqueous-ethanol Extractants.............................................................................129 11.1.2 Determination of Acrylonitrile Monomer in Acidic and Alkaline Extractants........................................................130 11.1.3 Determination of Acrylonitrile in 6% Hydrochloric Acid Extractant......................................................................131 11.1.4 Determination of Acrylonitrile Monomer in 5% Sodium Carbonate Extractant................................................131 11.1.5 Determination of Acrylonitrile in Light Liquid- Paraffin Extractant.................................................................133 11.1.6 Separation of Acrylonitrile from Light Liquid-Paraffin and n-Heptane Extractants....................................................133 11.1.7 Determination of Acrylonitrile in Aqueous, Acidic and Alkaline Extractants........................................................135 11.1.8 Determination of an Acrylonitrile in Aqueous Ethanol Extractant.................................................................136 11.1.9 Calculation of the Acrylonitrile Contents of the Extractants.......................................................................136 11.2 Determination of Styrene Monomer and Aromatic Hydrocarbons in Aqueous and Fatty (Liquid Paraffin) Extractants............................138 11.2.1 Determination of Styrene Monomer and Other Volatiles in Polystyrene.........................................................................138 11.3 Determination of Acrylate Monomers and Oligomers in Aqueous and Fatty Extractants...........................................................141 12 Analysis of Polymer Extraction Liquids Containing More Than One Migrant.................................................................................................... 153 12.1 Preliminary Solvent Extraction of Gross Additives from Aqueous and Alcoholic Extractants....................................................154 12.1.1 Extraction Test (Assuming the Extraction Test is Carried Out on 700/800 ml Scale).........................................154 12.1.2 Ether Extraction.....................................................................155 12.2 Separation of Individual Additives from Solvent Extract of Extractant Liquid...............................................................................155 (a) Mixture of Santonox R, Ionol CP and DLTDP............................155 12.2.1 Indirect Setermination of Additives on the Thin-layer Plate......157 (b) Mixture of Butylated Hydroxy Toluene (BHT) Antioxidant and 2-Hydroxy-4-n-octoxybenzophenone Light Stabiliser in Extractants..............................................................................161 12.2.2 Scaling of Operations.............................................................162 12.3 Ether Extraction of Extraction Liquid..................................................163 13 Determination of Additives and their Breakdown Products in Extractants......171 13.1 Determination of Lauric Diethanolamide and its Degradation Products in Aqueous Fatty Extraction Liquids....................................172 13.1.1 Determination of Lauric Diethanolamide and DEA in the Distilled Water Extractant............................................175 13.1.2 Determination of Lauric Diethanolamide and DEA in the Aqueous 5% Sodium Carbonate Extractant.................176 13.1.3 Determination of Lauric Diethanolamide and DEA in the 50% w/v Aqueous Ethyl Alcohol Extractant................176 13.1.4 Determination of Lauric Diethanolamide and Hydrolysis Products in the 5% w/v Aqueous Citric Acid Extractant......................................................................180 13.1.5 Determination of Lauric Diethanolamide in the Liquid Paraffin Extractant.................................................................181 13.2 Polymeric Plasticisers..........................................................................195 13.3 Polybutylene Adipate, Poly(1,2-Propylene Adipate) and Polybutylene Succinate.......................................................................196 13.4 Organosulfur Vulcanising Agents.......................................................198 14 Additive Migration Theory...........................................................................201 14.1 Polyethylene Naphthalate ..................................................................218 14.2 The Total Migration Concept.............................................................248 15 Gas Barrier Properties of Food Packaging Plastic Films................................259 16 Legislative Aspects of the Use of Additives in Packaging Plastics..................273 16.1 Regulatory System in the European Union..........................................273 16.2 The Regulatory System Existing in the UK.........................................280 16.3 Regulatory System Existing in the USA...............................................280 FDA compliance for Ultraviolet Electron Beam (EB) Coatings and Adhesives.....................................................................................290 17 Direct Determination of Migrants from Polymers into Foodstuffs................297 17.1 Antioxidants.......................................................................................297 17.2 Plasticisers..........................................................................................301 17.2.1 Olive Oil................................................................................301 17.2.2 Vegetables..............................................................................301 17.2.3 Meat......................................................................................301 17.2.4 Miscellaneous Foods..............................................................302 17.2.5 Hydrocarbons........................................................................302 17.3 Organotin Compounds.......................................................................302 17.4 Polyvinylpyrrolidone..........................................................................303 17.5 Benzoic Acid.......................................................................................303 17.6 Alkyl Citrates.....................................................................................303 17.7 Metals................................................................................................303 Abbreviations and Acronyms..............................................................................309