Lu Shih-Chieh, Liao Wan-Rou, Chen Sung-Fang
Department of Chemistry, National Taiwan Normal University.
Anal Sci. 2018;34(4):439-444. doi: 10.2116/analsci.17P528.
Resveratrol is one of representative ingredient in red wine, but its quantification is a challenge because of a complex and abundant matrix. In this study, two sample pretreatments, direct dilution and QuEChERS extraction, coupling LCMS analysis were examined for resveratrol quantification. Similar recoveries of 106.4 to 93.7% were obtained for direct dilution and QuEChERS, respectively. With the aid of condition optimization, QuEChERS extraction could concentrate the resveratrol from red wines to improve the detection sensitivity with a LOD value of 2.5 ng/mL, which is four-times greater than the direct dilution approach. As a result, the QuEChERS method can provide a high linearity within the concentration range of 5 - 500 ng/mL, in which direct dilution produced the linear calibration curve within the concentrations of 25 - 500 ng/mL. A high consistency was obtained for both approaches in which intra-day precisions were within 0.5 to 7.2% (n = 3), and the inter-day precisions were within 7.8 to 16.0% (n = 9). Overall, the sample pretreatment of QuEChERS can effectively reduce the matrix effect, which leads LCMS to quantify the low resveratrol abundance of 8.0 ppb in each red wine sample, which is not achieved with the direct dilution approach.
白藜芦醇是红酒中的代表性成分之一，但由于其基质复杂且成分丰富，对其进行定量分析具有挑战性。在本研究中，考察了直接稀释和QuEChERS萃取这两种样品前处理方法与液相色谱-质谱联用（LCMS）分析相结合用于白藜芦醇定量分析的情况。直接稀释法和QuEChERS法分别获得了106.4%至93.7%的相似回收率。通过条件优化，QuEChERS萃取法可将红酒中的白藜芦醇浓缩，以提高检测灵敏度，其检测限为2.5 ng/mL，比直接稀释法高四倍。结果表明，QuEChERS法在5 - 500 ng/mL的浓度范围内具有良好的线性，而直接稀释法在25 - 500 ng/mL的浓度范围内得到线性校准曲线。两种方法的日内精密度在0.5%至7.2%（n = 3）之间，日间精密度在7.8%至16.0%（n = 9）之间，一致性较高。总体而言，QuEChERS样品前处理可有效降低基质效应，从而使LCMS能够对每个红酒样品中低至8.0 ppb的白藜芦醇含量进行定量，而直接稀释法无法做到这一点。
