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试样经透析预处理。于pH 4用乙醚提取分离干扰物——山梨酸。利用紫外吸收光谱法可以简易的测定糖精含量,也可以同时测定山梨酸。把0.02N NaOH 30ml加入盛有切细或磨碎的试样20 g的玻璃纸筒中,随加随混和。然后挂于盛有300 ml 0.02 N NaOH的300 ml广口瓶中透析20～24小时。取50 ml透析液,加1NHCl 1 ml和醋酸缓冲溶液10ml,调至pH 4,用乙醚40 ml提取4次,此液留作山梨酸分析用。水层中加HCl(1→2)10 ml,用氯化钠18 g进行饱和后,用乙醚30 ml提取二次。用氯化钠饱和的1%HCl溶液20 ml洗乙醚层,再用2%NaHCO_3溶液10 ml提取二次,此液作塘精测定。用50 ml蒸馏水洗涤最初的乙醚层,用1%
Sample pretreatment by dialysis. Sorbitol was separated by extraction with ether at pH 4. The use of UV absorption spectrometry can easily determine the content of saccharin, sorbic acid can also be determined at the same time. Add 30 ml of 0.02 N NaOH to a 20 g glass-lined cell containing finely-divided or ground samples and mix with it. Then hung on a 300 ml jar containing 300 ml of 0.02 N NaOH and dialyzed for 20-24 hours. Take 50 ml of dialysis solution, add 1N HCl and 10 ml acetic acid buffer solution, adjust to pH 4, and extract with 40 ml of ether for 4 times. The solution is reserved for sorbic acid analysis. Water layer add HCl (1 → 2) 10 ml, saturated with sodium chloride 18 g, extracted with diethyl ether 30 ml twice. 20 ml of 1% HCl solution saturated with sodium chloride was used to wash the ether layer, and then extracted twice with 10 ml of 2% NaHCO 3 solution. The liquid was determined as pond extract. The original ether layer was washed with 50 ml of distilled water, washed with 1%