顶空固相微萃取-气相色谱法测定山楂果胶酯化度

Determination of the esterification degree of hawthorn pectin by headspace solid-phase microexrtaction and gas chromatography

利用顶空固相微萃取与气相色谱联用（HS-SPME-GC）的方法测定山楂果胶的酯化度（包括甲酯化和乙酯化）,对影响检测结果的萃取头种类、萃取温度、平衡时间、萃取时间、盐离子浓度、解吸温度、解吸时间进行了优化。结果表明,HS-SPME-GC测定山楂果胶酯化度较优条件为：5 m L山楂果胶溶液中加48.8%硫酸钠,在40℃下平衡20 min,用75μm CAR-PDMS萃取头在40℃下萃取30 min,然后在280℃的GC进样口解析60 s。该方法线性良好r≥0.9983,检出限10~15 mg/L,加标回收率为95.6%~116.2%。该方法快速、简便、准确。

Headspace solid- phase microextraction and gas chromatography（ HS- SPME- GC） were used for the qualitative determination of the esterification degree（ methyl esterification and ethyl esterification） of haw pectin samples.HS- SPME experimental conditions,such as the type of fibers,extraction temperature,balance time,extraction time,salt concentrations,desorption temperature,desorption time were optimized.The best HS- SPMEGC performance was achieved under the following conditions： 5 m L pectin solution in headspace glass vial with addition of 48.8% Na2SO4,20 min balance time and 30 min extraction time at 40 ℃ using 75 μm CAR-PDMS fiber and 60 s desorption time in the GC inlet at 280 ℃.The correlation coefficient r was greater than 0.9983,the detection limits of the method were 10~15 mg / L,the recovery rates were 95.6% ~116.2%.The proposed method is simple,fast and accurate with high reproducibility.