herbal supplement hplc analysisEach day, I receive news about research studies on benefits of phenols and polyphenols, such as this one in which European scientists are to conduct experiments and clinical trials to work out the beneficial effects of polyphenols and peptides on cardiovascular disease risk or the one in researchers could not find any high-quality evidence that antioxidant supplements help to increase a woman’s chances of having a baby. (Links to stories.) But, the popularity of nutritional supplements continues unabated.

Here, I am pleased to present a gradient HPLC spectro-electro array platform that can simultaneously separate and quantify over 50 different phytochemicals commonly found in a large number of herbs, spices, and beverages! The system setup includes one of our biocomatible HPLC systems (Thermo Scientific Dionex UltiMate 3000 HPLC system) equipped with an autosampler (Thermo Scientific Dionex UltiMate 3000 Biocompatible Autosampler), our electrode array detector (Thermo Scientific Dionex CoulArray Coulometric Array Detector), and one of our high-performance reversed-phase HPLC columns (Thermo Scientific Acclaim 120 column).

A bit about our electrode array detector. It uses a series of flow-through electrochemical sensors to detect, identify and characterize analytes. Co-eluting compounds are readily resolved based on their ease of oxidation (or reduction). This ability of the detector to be used with gradient elution significantly increases the number of analytes that can be measured simultaneously, even in crude plant extracts. This approach extends the range of analytes typically measured by PDA alone, and has the sensitivity and selectivity to study metabolism of secondary analytes following consumption by humans.

The method is described in Application Note 1063, Targeted Analyses of Secondary Metabolites in Herbs, Spices, and Beverages Using a Novel Spectro-Electro Array Platform (downloadable PDF) in which the detector uses unique three-dimensional voltammetric resolution to enable compound separation superior to that of traditional spectrometric techniques. This method can also measure the antioxidant capacity of a sample, as well as the contribution of individual groups of antioxidants to that total capacity. The method was able to resolve over 50 analytes in 45 minutes, with low picogram sensitivity.

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Natural products included in the study: crude extracts of a variety of natural products, supplements (ginseng, black cohosh, St. John’s wort, and ginkgo), beverages (black tea, green tea, wine, beer, whisky, and bourbon), culinary herbs (oregano, rosemary, sage, and thyme), and spices (cloves and nutmeg).

Resources for HPLC Analysis of Natural Products

Here are some downloadable poster notes plus links to our blog that you might find useful in your work.

If you have questions on the platform, method, or detector presented in this blog post, do enter them in the Comments box below; our experts look forward to hearing from you.