Dãnet A F, Badea M, Aboul-Enein H Y
University of Bucharest, Faculty of Chemistry, PO Box 164, Bucharest 15, Romania.
Luminescence. 2000 Sep-Oct;15(5):305-9. doi: 10.1002/1522-7243(200009/10)15:5<305::AID-BIO599>3.0.CO;2-X.
A simple, selective and rapid method for determination of ascorbic acid from fruit juices was developed by combining a flow injection analysis (FIA) system with a chemiluminometric detector and a reactor with L-ascorbate oxidase immobilized on controlled pore glass. It was found that some reducing agents (eg ascorbic acid and mercaptoacetic acid) give chemiluminescence with luminol in the presence of hexacyanoferrate (III) in an alkaline solution. We used this new type of chemiluminescent reaction for the enzymatic determination of ascorbic acid. The background substraction method was used in order to avoid interference during ascorbic acid determination. Accordingly, two chemiluminometric signals were registered for each determination, one signal corresponding to the sample that passed through the enzymatic reactor that decomposed the ascorbic acid completely, and the second signal corresponding to the sample that does not pass through the reactor. The difference between the two signals corresponds to ascorbic acid from the sample. The linear range of the method was 10-1000 micromol/L of ascorbic acid and the detection limit was 5 micromol/L The throughput was four samples/h and RSD 3.13% (n = 10). This method was applied for determination of ascorbic in fruit juices. The results were compared with those found by the reference method, based on titrimetric determination with 2,6-dichlorophenolindophenol, and the concordance was excellent.
通过将流动注射分析（FIA）系统与化学发光检测器以及固定有L - 抗坏血酸氧化酶的可控孔径玻璃反应器相结合，开发了一种简单、选择性好且快速的测定果汁中抗坏血酸的方法。研究发现，在碱性溶液中，一些还原剂（如抗坏血酸和巯基乙酸）在高铁氰酸盐（III）存在下与鲁米诺发生化学发光反应。我们利用这种新型化学发光反应来酶法测定抗坏血酸。为避免抗坏血酸测定过程中的干扰，采用了背景扣除法。因此，每次测定记录两个化学发光信号，一个信号对应通过完全分解抗坏血酸的酶反应器的样品，第二个信号对应未通过反应器的样品。两个信号的差值对应样品中的抗坏血酸。该方法的线性范围为抗坏血酸10 - 1000 μmol/L，检测限为5 μmol/L，通量为每小时四个样品，相对标准偏差为3.13%（n = 10）。该方法用于测定果汁中的抗坏血酸。将结果与基于用2,6 - 二氯酚靛酚滴定法的参考方法所得结果进行比较，一致性良好。
