Stellenbosch University , Department of Chemistry and Polymer Science, Private Bag X1, Matieland, Stellenbosch, Western Cape 7602, South Africa.
Anal Chem. 2013 Oct 1;85(19):9107-15. doi: 10.1021/ac401896r. Epub 2013 Sep 13.
Despite the significant importance of tannins in viticulture and enology, relatively little is known about the detailed chemical composition of these molecules. This is due to challenges associated with the accurate analytical determination of the highly structurally diverse proanthocyanidins which comprise tannins. In this contribution, we address this limitation by demonstrating how online comprehensive two-dimensional liquid chromatography (LC × LC) coupled to high resolution mass spectrometry (HR-MS) can be exploited as a powerful analytical approach for the detailed characterization of grape seed tannins. Hydrophilic interaction chromatography (HILIC) and reversed-phase liquid chromatography (RP-LC) were employed in the two dimensions to provide complementary information in terms of separation according to hydrophilicity and hydrophobicity, respectively. Online coupling of HILIC × RP-LC with fluorescence detection and electrospray ionization MS delivered high resolution analysis in a practical analysis time, while allowing selective detection and facilitating compound identification. Time-of-flight (TOF) MS provided high acquisition rates and sensitivity coupled to accurate mass information, which allowed detection of procyanidins up to a degree of polymerization (DP) of 16 and a degree of galloylation up to 8 in a red grape seed extract. This analytical methodology promises to shed new light on these important grape constituents and potentially on their evolution during wine production.
尽管单宁在葡萄栽培学和酿酒学中具有重要意义，但人们对这些分子的详细化学组成知之甚少。这是由于在准确分析包含单宁的高度结构多样的原花青素方面存在挑战。在本研究中，我们通过演示如何利用在线全面二维液相色谱（LC×LC）与高分辨率质谱（HR-MS）联用作为一种强大的分析方法来详细表征葡萄籽单宁，解决了这一限制。亲水相互作用色谱（HILIC）和反相液相色谱（RP-LC）分别在两个维度上用于根据亲水性和疏水性提供互补的分离信息。在线将 HILIC×RP-LC 与荧光检测和电喷雾电离 MS 耦合，可在实际分析时间内实现高分辨率分析，同时允许选择性检测并促进化合物鉴定。飞行时间（TOF）MS 提供了高采集率和灵敏度，并结合了准确的质量信息，可在红酒籽提取物中检测到聚合度高达 16 的原花青素和聚合度高达 8 的没食子酰化程度。这种分析方法有望为这些重要的葡萄成分及其在葡萄酒生产过程中的演变提供新的见解。
