Appendix 1: method procedure summaries analysis of

E355–7, E359: Adipic acid and its salts 179 Table 14.1 Summary of methods for adipic acid in foods a Method Matrix Sample preparation Method conditions Detection Reference GC Crackling An alkaline solution of sample was The adipic acid in the concentrate FID 1 candy and extracted with ethyl ether. H 2 SO 4 was was methylated using the soft drinks added to water layer pH2. The diazomethane method acidified layer was saturated with NaCl and then extracted with ether. After drying the ether layer was concentrated Capillary zone Wine 7.5 mM 4-aminobenzoic acid, Indirect UV absorbance 4 electrophoresis 10.5 mM trihydroxymethyl- and direct conductivity CZE aminomethane, 0.1 mM tetra- simultaneously decyltrimethylammonium bromide pH 7.0 with LiOH GC Food Olive oil simulant diluted with Di2-ethylhexyladipate DEHA FID at 370 ºC 5 simulants n- heptane. Other simulants not diluted Retention time 8.6 min. Column: BPX5 0.25 µm film. Temperature programmed 100–360 ºC. Carrier gas: helium. Cold on column injector GC–MS Food Adipic acid esters migrated into GC–MS 6 wrapping n -heptane 180 Analytical methods for food additives Table 14.1 cont’d Method Matrix Sample preparation Method conditions Detection Reference GC–MS Packaging 1 g of packaging material was Soxhlet Di2-ethylhexyladipate DEHA FID at 370 ºC 7 materials extracted with chloroform–methanol Column: HP-5MS 0.25 µm film. 2:1, 50 mL for 6 h. Extracts Temperature programmed transferred to 50 mL vol flask and 70–280 ºC. Carrier gas: helium. made up to volume with chloroform– Split injector 1:25, 2 µL injection methanol. 1 mL transferred to vials for GC–MS analysis GC Starch Total adipate: sample saponified with Column: CP-sil 5CB 50 m × FID at 300 ºC 8 alkali and extracted with ethyl acetate, 0.32 mm, 0.12 µm film. evaporated and silylated. Free adipate: Temperature programmed aqueous extraction, then extracted 4 × 130–290 ºC. Carrier gas: helium. with ethyl acetate, evaporated and 0.3 µL injection. silylated b Method Matrix Sample preparationextraction Column Mobile phase Detection Reference HPLC Urine Extracted with diethyl ether and TSK-Gel, Acetonitrile–water Fluorescence 3 converted into fluorescent derivatives octadecyl-silane 85:15, vv, 1.5 at em 412 nm, with 9-anthryldiazomethane RP-type mLmin, 20 µL ex 365 nm injection Ion-exclusion Ice lollies TSK-Gel, SCX 2 mM H 3 PO 4 – 210 nm 2 chromatography H + form at 40 ºC 1.5 acetonitrile at 1 mLmin