Kapillargaschromatographisches Pr�fverfahren auf Zus�tze von synthetischer DL-�pfels�ure zu Obsterzeugnissen

A method for the determination of D-malic acid in products of fruits is presented. After addition of undecanoic acid as internal standard the dehydrated sample is extractive methylated by conc. hydrochloric acid, methanol and anhydrous magnesium sulfate. The extract is subjected to gaschromatographic separation on a chiral phase. Quantification of D-malic acid is done by the method of standard addition. The relative standard deviation is in the range of 1,8–4,4%, the detection limit 2,1–2,7 mg/l, the limit of quantitation 3,6–4,1 mg/l. Measures of fruit juice, fruit wine, wine and vinegar are tabulated.