[Residues of ethylene chlorohydrin (ECH) in infusions of cocoa and in chocolate (author's transl)].

With a sensitive method residues of 0.2--0.6 ppm ECH are found in commercial and bendtop infusions of cocoa and 1.8--5.6 ppm ECH in chocolate. The balance is established with time between ECH and ethylene oxide (EO) in the boiling infusion and the distillate depending on time. It is found that the ECH concentration in the infusion is reduced in 15 min to 1/7 by evaporation alone. No reaction to EO or ethylene glycol or other metabolites is detectable. For the determination alkali is added to the sample, followed by distillation of any formed EO into dilute sulfuric acid, where ethylene glycol is oxidized to formaldehyd according to Malaprade. This is distilled off for further enrichment and determined according to Bremanis by photometry at 570 nm. The determination for limit was to 0.01 ppm, the standard deviation is s = 0.0034 ppm (N = 30), the yield 99.8%. The sensitivity may be increased tenfold by increasing sample size.