超高效液相色谱测定冷冻研磨甘薯植株中酚酸及其分布

Determination of Phenolic Acids and Their Distribution in Freeze Ground Aerial Parts of Different Sweetpotato Varieties by Ultra-High Performance Liquid Chromatography

建立超高效液相色谱法分析13种甘薯品种中不同植株酚酸的含量与分布。结果表明,在萃取溶剂中加入0.2%亚硫酸氢钠可以提高咖啡酸和咖啡酰奎宁酸类成分的回收率和稳定性。不同的样品预处理方法比较发现,冷冻研磨获得的酚酸含量最高,其次是冻干、烘干、晒干和直接匀浆。方法快速、稳定、灵敏度高,加标回收率为99.5%~103.1%,相对标准偏差为0.3%~1.2%;检出限为3.6~21.4 ng/mL,定量限为12.1~71.3 ng/mL。13种甘薯材料的叶片中总酚酸含量(以干基计)范围为18.0~44.8 g/kg,叶柄为0.7~11.9 g/kg,茎为0.3~9.7 g/kg,包括咖啡酸、3-咖啡酰奎宁酸、4-咖啡酰奎宁酸、5-咖啡酰奎宁酸、3,4-双咖啡酰奎宁酸、3,5-双咖啡酰奎宁酸、4,5-双咖啡酰奎宁酸和3,4,5-三咖啡酰奎宁酸。不同材料甘薯植株中酚酸含量存在明显差异,含量最丰富的酚酸是双咖啡酰奎宁酸,而不同部位中甘薯叶片含量最高。

In this study, an ultra-high performance liquid chromatography(UPLC) method was established to analyze the distribution of phenolic acids in aerial parts of 13 sweetpotato varieties. The results showed that addition of 0.2% sodium hydrogen sulfite to the extraction solvent could improve the recovery and stability of caffeic acid(CA) and caffeoylquinic acids(CQAs). Among the tested pretreatment methods, freeze grinding resulted in the highest content of phenolic acids, followed by freeze drying, oven drying, sun drying and homogenization. The UPLC method was fast, stable and highly sensitive with spiked recoveries of 99.5%-103.1%, and precision(expressed as relative standard deviation, RSD) of 0.3%-1.2%. The limit of detection(LOD) and the limit of quantification(LOQ) were 3.6-21.4 and 12.1-71.3 ng/mL, respectively. The contents of total CA and CQAs including CA, 3-CQA, 4-CQA, 5-CQA, 3,4-diCQA, 3,5-diCQA, 4,5-diCQA and 3,4,5-triCQA in the leaves, petioles and stems of sweatpotato ranged from 18.0-44.8, 0.7-11.9, and 0.3-9.7 g/kg dry sample, respectively. The contents of phenolic acids in different sweetpotato varieties were obviously different from each other, with dicaffeoylquinic acids(diCQAs) being the most abundant phenolic acid in all varieties. Moreover, diCQAs were the most abundant in the leaves among the three parts.