固相微萃取-紫外可见光谱联用技术在叶绿素测定中的应用

Analysis of Chlorophyll in Plant Leaves Using Solid-phase Microextraction Coupled with Ultraviolet-visible Absorption Spectroscopy

通过固相微萃取与紫外可见光谱联用，以壳聚糖为固化溶剂，实现了对蔬菜叶片中叶绿素a和叶绿素b含量的快速测定．壳聚糖膜对叶绿素具有足够高的富集倍数，并且该膜均匀、透明、机械强度好．实验考察了萃取时间、离子强度、pH及能量供给方式对萃取效率的影响．在优化的实验条件下，叶绿素a和叶绿素b的重现性（RSD）分别为7．1％和8．4％，检出限（3σ）分别为0．155mg／L和0．099mg／L，回收率为92．3％～97．9％．同时，与传统叶绿素分析方法比较，结果令人满意．

A rapid and simple method using solid-phase microextraction coupled with ultraviolet-visible absorption spectroscopy for the analysis of chlorophyll a and chlorophyll b in plant leaves is presented. It was simply in-expensive and free solvent. Chitosan, a kind of natural polymers containing plenty of amido and hydroxyl,was used as solidified organic solvent to extract chlorophyll for the first time. After a chip of chitosan was immersed in an aqueous sample,chlorophyll a began to partition into the polymer. The system may reach a complete equilibrium in 80 min. Since the chitosan membrane is enough tough and uniformity that it may be detected by ultraviolet-visible absorption spectroscopy. Several factors affecting the extraction efficiency such as extract time, ion intensity and pH were investigated. Under optimum condition, the reproducibility of the method was 7.10% for chlorophyll a and 8.40% for chlorophyll b, respectively. The detection limit （3σ） was 0. 155 mg/L for chlorophyll a and 0. 099 mg/L for chlorophyll b, respectively. The recovery was within the range of 92. 3%-97.9%. Meanwhile, the performance of the method was compared with the traditional method and excellent agreements were observed between the methods.