Gertz C, Hild J
Z Lebensm Unters Forsch. 1980 Feb;170(2):103-9. doi: 10.1007/BF01093686.
In the Federal Republik of Germany formic acid, benzoic acid, propionic acid, sorbic acid and the esters of p-hydroxybenzoic acid were permitted as food-additives. They can be extracted together from acidified materials by means of perforation with ether. During distillation the preservatives are fixed by sodium hydroxide. The alkaline extract can then be used directly for various photometric (Part I) and chromatographic (Part II) determinations. All preservatives except propionic acid can be identified and determined by simple and specific color reaction. From the alkaline extract, benzoic acid, sorbic acid and the esters of p-hydroxybenzoic acid can be separated as the free acid by thin-layer chromatography on silica gel. Determination of the remission at 232 nm and 260 nm and of the reduction in fluorescence are employed for the photometric in situ evaluation of the thin-layer chromatograms.
在德意志联邦共和国，甲酸、苯甲酸、丙酸、山梨酸以及对羟基苯甲酸酯被允许用作食品添加剂。它们可以通过用乙醚穿孔从酸化物料中一起萃取出来。在蒸馏过程中，防腐剂用氢氧化钠固定。然后碱性提取物可直接用于各种光度法（第一部分）和色谱法（第二部分）测定。除丙酸外，所有防腐剂都可以通过简单且特定的显色反应进行鉴定和测定。从碱性提取物中，苯甲酸、山梨酸以及对羟基苯甲酸酯可以通过硅胶薄层色谱法分离为游离酸。通过测定在232nm和260nm处的吸光度以及荧光的降低来对薄层色谱图进行光度法原位评估。
