Evaporative light scattering detection (ELSD) for the analysis of natural products

Many important herbal drugs (e.g. ginkgo, black cohosh, soy) contain bioactive compounds possessing no chromophore, thus detection techniques other UV are needed for their identification and standardization. Evaporative light scattering is one of the possible alternatives, but despite the fact that this technique has been developed more than 30 years ago, it is still considered to be an exotic detection alternative, with few applications at hand. Over the last decade ELSD has steadily evolved, so that from today's point of view it can be considered a reliable, economic and versatile mode of detection. In this article the basic principles of ELSD are described and advantages / disadvantages compared to other LC detectors (IR, MS) are discussed. An overview of recent applications in natural products analysis (mainly carbohydrates, lipids, saponins, terpenes) is given. The wide range of possible analytes and matrices should indicate the impact of ELSD in this field so far, and arouse further interest in a novel, yet old detection method.