Antioxidant activity evaluation of trace sample by the spot measurement of singlet oxygen luminescence lifetime

为了评价微量天然物质的抗氧化活性，建立了一种用0.4mm光纤探针测量单线态氧近红外发光寿命的方法。单线态氧发光的时间演变成功地从测量小于0.1毫升的解决方案，也水凝胶样品的斑点方法。测定了痕量样品（如0.05 mg类胡萝卜素异构体）以及水凝胶样品中猝灭剂的猝灭速率常数。研究了辣椒碱等香料亲脂性成分在环糊精水溶液中的单线态氧猝灭活性与化学结构的关系。然而，在现场测量中，光损伤往往发生在测试材料和/或光敏剂的积累时间（10分钟）。积累时间短（< 1 min），有望将点扫描法应用于抗氧化剂的测定。

In order to evaluate antioxidant activities of trace amount of natural materials, a method of measuring lifetimes of singlet oxygen near-infrared luminescence using a fiber-spot probe (0.4 mm) was developed. Time-evolutions of singlet oxygen luminescence were successfully obtained from measurements of less than 0.1 mL of solutions and also hydrogel samples by the spot method. The quenching rate constants for trace amount of samples such as 0.05 mg of carotenoid isomers, and also that of the quencher in hydro-gel samples were determined. The relationship between singlet oxygen quenching activity and chemical structure for the lipophilic constituents of spices such as capsaicin were investigated in the cyclodextrin aqueous solution. However, in the spot measurements, the photo-damages often occurred in test materials and/or photosensitizers in the accumulation time (10 min). The shorter accumulation time (< 1 min) is hopeful for applying the spot-scan method to the antioxidant assay.