【摘要】 对测定果蔬及饮料中的Vc含量的碱处理背景校正UV法进行实验研究。Vc在碱性条件下不稳定,加NaOH溶液使pH达12～13,10min其破坏率达95％以上。利用碱处理前后在243nm处吸光度的变化消除背景干扰,比色液的Vc含最在0.3～50μg/ml范围内服从Beer—Lambert定律。经过对UV法准确度、精确度、回收率以及几十种物质对测定干扰试验表明,这一方法快速、准确、可靠,适用于除了含有高浓度咖啡因、糖精、焦糖和单宁酸以外的果蔬及饮料的Vc测定。更多还原

【Abstract】 Direct ultrovoilet spectrophotometry through alkline treatment was developed as an analytical method. The optical maximum absorption of Vc was243nm when pH is about 2, More than 95% of Vc was destroyed after 10min under pH 12～13. Absolute detection limit was 0.3～25μg/ml. The method is suitable to content within 3.75～625mg/100g of fresh fruits and vegetables and 15～1250μg/ml of drinks. Many compounds including natural substance and additives which may interfere with analysis results were studied.更多还原