测定营养物的化学成份,目前广泛采用近代化学分析法,但对样品的纯度要求较高,须经较复杂的分离手段。例如测定抗坏血酸的含量,用高效液相法(HPLC)、离子交换层析法、安培滴定法等都要求样品高纯,难以用于测定生物样品中的抗坏血酸含量。如用微量荧光比色法,无法区别开抗坏血酸和其氧化降解产物脱氢抗坏血酸。 Determination of the chemical composition of nutrients, the current extensive use of modern chemical analysis, but the purity of the sample requires a higher, subject to more complex separation methods. For example, the content of ascorbic acid is determined, and the sample is required to be highly pure by high-performance liquid chromatography (HPLC), ion exchange chromatography, amperometric titration, etc., and thus it is difficult to measure the ascorbic acid content in the biological sample. Such as the use of trace fluorescent colorimetric method, can not distinguish between ascorbic acid and its oxidative degradation products dehydroascorbic acid.