Recommendations References analytical methods for food additives

E122: Azorubine 19 Table 2.1 Summary of methods for azorubine in foods a Method Matrix Sample Column Mobile phase Detection Reference preparationextraction IP-RP-HPLC Lemonade, Ion pairs with cetylpyridinium Spherisorb C8 Gradient elution 1.5 mLmin Diode-array 2 cake crumb, chloride from aqueous solutions with phosphate buffer containing at 520 nm skimmed milk into n-butanol cetylpyridinium chloride, acetonitrile and methanol RP-HPLC Bitters Diluted with water and filtered Nova-Pak C18 Gradient elution 2 mLmin 520 nm 3 using methanol and 0.1 M sodium phosphate buffer at pH 7 HPLC Beverages, Diluted with water and filtered Nova-Pak C18 Gradient elution 1.5 mLmin 520 nm 4 gelatine, with methanol–phosphate buffer at syrups pH 7 1:4 containing 5 mM tetrabutyl ammonium bromide HPLC Yogurt Shaken with 5 NH 3 . Acetone MicroPak Gradient elution using TBA in 254 nm 6 added and shaken. Centrifuged MCH-10 methanol diluted with methanol– supernatant concentrated to phosphate buffer at pH 7±0.05 remove acetone. Adjust to pH 4. Shake with polyamide. Centrifuge. The polyamide washed 3× with water and then shaken with MeOH–aqNH 3 19:1 HPLC Confect- Sweets stirred in methanol. Spherisorb Water–acetonitrile 7:3 520 nm 7 ionery Methanol extract diluted 1:10 ODS-2 with containing 5 mM octylamine in water and filtered 0.45 µm LiChrospher orthophosphoric acid at pH 6.4 before injection RP-18 guard 1 mLmin column 20 Analytical methods for food additives Table 2.1 cont’d b Method Matrix Sample preparation Method conditions Detection Reference Capillary zone Non-alcoholic Samples used as is or diluted A background solution 216 nm 5 electrophoresis beverages and with water consisting of 15 mM borate CZE fruit flavoured buffer at pH 10.5, hydrodynamic syrups injection and a 20 kV separation voltage Spectro- Beverages, Samples diluted in 5 mL acetate Analysed by spectrophotometry 427 nm 8 photometric gelatine, syrups buffer and diluted to 25 mL with using a Beckman DU-70 instrument water Solid-phase Colourings Sample solution mixed with 1 M The mixture was shaken for 15 min Absorbance 9 spectro- caramel, HCl, ethanol sufficient for a 10 then the gel beads were filtered off, measured at photometry confectionery conc., water and Sephadex DEAE packed into a 1 mm cell and 525 nm and A-25 gel absorbance measured 800 nm Rapid clean-up Various foods Liquid samples as is. Solid Colour separated on reverse phase TLC or 10 method for samples dissolved in water and C18 Sep-Pak cartridge and eluted spectrophotometric spectro- filtered through sintered glass with aqueous isopropanol solutions photometric and filter TLC methods Spectro- Soft drinks Ion-pair formation with octadecyl- Extraction of the ion-pair into 550 nm 11 photometric trimethylammonium bromide at n -butanol pH 5.6