海带中叶绿素的提取及间接测定方法研究

采用超声波提取法对海带中叶绿素进行提取，原子吸收光谱法对提取出的叶绿素中的镁离子进行测定，从而间接得出海带中叶绿素的含量。结果表明，超声波提取叶绿素的最佳工艺条件：以无水乙醇与丙酮体积比1:1 的混合液为提取剂，按料液比2:15(g/mL)，在室温下超声波选择200W 的功率提取2 次，每次20min。反萃取的最佳测定工艺条件：用浓度为0.9mol/L 的盐酸15mL 进行反萃取15min。原子吸收法测定检出限为0.008μg/mL，海带中叶绿素的含量5.486mg/g，相对标准偏差0.675%，回收率97.7%。此方法表明：原子吸收光谱法受干扰程度小，且精密度、灵敏度和准确度较高。

Extraction and Indirect Measurement of Chlorophyll in Kelp

Five technological conditions for the ultrasonic-assisted extraction of chlorophyll from kelp were investigated, and the back extraction of the extract with chlorohydric acid for the displacement of magnesium ions by hydrogen ions was optimized using single factor and orthogonal array design methods. Displaced magnesium ions were assayed by atomic absorption spectrometric (AAS) method. Therefore, the content of chlorophyll in kelp could be calculated from obtained magnesium concentration data. Based on these studies, an indirect method for quantifying chlorophyll in kelp has been set up. The optimal conditions for extracting chlorophyll based on the use of an absolute ethanol/acetone mixture as the extraction solvent were found to be: solid/ liquid ratio (g/mL) 2:15 and ultrasonic power 200 W for twice extraction for 20 min each time. Chlorohydric acid concentration of 0.9 mol/L, chlorohydric acid amount of 15 mL and back extraction duration of 15 min were found optimal for the displacement of magnesium ions. The limit of detection of AAS method was 0.008 μg/mL. The average content of chlorophyll in kelp (n = 5) was 5.486 mg/g, with a relative standard deviation of 0.675% and the average spike recovery for chlorophyll was 97.7%. The developed method for chlorophyll determination has the advantages of little disturbance and high precision, sensitivity and accuracy.