Caffeine in Your Drink: Natural or Synthetic?

Instrumental Analytical Chemistry, University of Duisburg-Essen, Essen, Germany.
Analytical Chemistry (Impact Factor: 5.64). 02/2012; 84(6):2805-10. DOI: 10.1021/ac203197d
Source: PubMed


Owing to possible adulteration and health concerns, it is important to discriminate between natural and synthetic food ingredients. A new method for compound-specific isotope analysis (CSIA) by coupling high-temperature reversed-phase liquid chromatography to isotope ratio mass spectrometry (HT-RPLC/IRMS) was developed for discrimination of natural and synthetic caffeine contained in all types of drinks. The analytical parameters such as stationary phase, column inner diameter, and column temperature were optimized for the separation of caffeine directly from drinks (without extraction). On the basis of the carbon isotope analysis of 42 natural caffeine samples including coffee beans, tea leaves, guaraná powder, and maté leaves, and 20 synthetic caffeine samples from different sources by high-temperature reversed-phase liquid chromatography coupled to isotope ratio mass spectrometry, it is concluded that there are two distinguishable groups of caffeine δ(13)C-values: one between -25 and -32‰ for natural caffeine, and the other between -33 and -38‰ for synthetic caffeine. Isotope analysis by HT-RPLC/IRMS has been applied to identify the caffeine source in 38 drinks. Four mislabeled products were detected due to added but nonlabeled synthetic caffeine with δ(13)C-values lower than -33‰. This work is the first application of HT-RPLC/IRMS to real-world food samples, which showed several advantages: simple sample preparation (only dilution), high throughput, long-term column stability, and high precision of δ(13)C-value. Thus, HT-RPLC/IRMS can be a very promising tool in stable isotope analysis of nonvolatile compounds.

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    • "In combination with similar fragmentation patterns (LC/MSn, n = 2-3), relative hydrophobicity and fragmentation analogy were also harnessed to distinguish between two isomeric classes of CGA (CGA lactones and cinnamoylshikimate) which are formed from CGA by loss of water at high processing temperatures [135]. Interestingly, a high temperature reverse phase liquid chromatography coupled with isotope ratio mass spectrometry (HT-RPLC/IRMS) was employed to distinguish between natural and synthetic caffeine in coffee drinks, without the painful need for extraction, by using δ13 C values (between 25 and 32‰ for natural caffeine, and between 33 and 38‰ for synthetic caffeine) as distinguishable groups [136]. This method will be a special aid in the fight against counterfeiting and adulteration of coffee products. "
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    ABSTRACT: Production of coffee beans is an important lifeline for the economy of several countries in Latin America, Africa, and Asia. The brew from this well sought for cash crop is readily consumed due to its good sensory qualities owing to the presence of many micronutrients. Some of these chemical compounds possess biological activities, including antiproliferative, antioxidant, and antimicrobial effects. Four representative groups of these micronutrients, namely, caffeine, chlorogenic acid, diterpenes, and trigonelline, play key roles in these bioactive effects of coffee. In order to guarantee the quality of coffee products and to protect consumer interest and safeguard their well-being, it is extremely important to employ sensitive and accurate analytical methods in the characterization and quantitative determination of these bioactive constituents. This review aims to present recent applications in this regard.
    Full-text · Article · Jan 2014
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    • "As an increased number of people choose natural products because they associated that with health, the origin of caffeine matters for the consumer. Such worry is reflected in the development of methods to discriminate natural and synthetic caffeine (Zhang et al. 2012). About 4 years ago, a company contacted me to explore the possibility of a coffee plantation aimed to remove caffeine from the leaves, as the market for natural caffeine was increasing while the market for decaf coffee was not maintaining the same pace to attend the demand. "
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    ABSTRACT: The popularity of coffee as a beverage has its origin in the stimulant effect of caffeine. However, a market for decaffeinated (decaf) coffee developed when a variety of health problems appeared to be related with caffeine consumption. The caffeine obtained from the decaffeination is mainly used by pharmaceutical, cola-type soft drinks and cosmetic industries and although decaf coffee amounts to about 10% of the global coffee market, the need for caffeine by these industries is much bigger than is produced. With the increasing consumer appeal for natural products, which is related to a healthier life style, natural caffeine is missing in the market and is being replaced by the synthetic molecule, as has been shown by modern detection techniques. Here, I briefly discuss that while much attention has been paid on decaf coffee, perhaps natural caffeine has become more important and the by-product may now be decaf coffee.
    Preview · Article · Jul 2012
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    ABSTRACT: The interest in compound-specific isotope analysis for product authenticity control and source differentiation in environmental sciences has grown rapidly during the last decade. However, the isotopic analysis of very polar analytes is a challenging task due to the lack of suitable chromatographic separation techniques which can be used coupled to isotope ratio mass spectrometry. In this work, we present the first method to measure carbon isotope compositions of the widely applied herbicide glyphosate and its metabolite aminomethylphosphonic acid (AMPA) by liquid chromatography coupled to isotope ratio mass spectrometry. We demonstrate that this analysis can be carried out either in cation exchange or in reversed-phase separation modes. The reversed-phase separation yields a better performance in terms of resolution compared with the cation exchange method. The measurement of commercial glyphosate herbicide samples show its principal applicability and reveals a wide range of δ(13)C values between -24 and -34 ‰ for different manufacturers. The absolute minimum amounts required to perform a precise and accurate determination of carbon isotope compositions of glyphosate and AMPA were in the sub-microgram range. The method proposed is sensitive enough to further perform the experiments that are necessary to better understand the carbon isotope fractionation associated to the natural degradation of glyphosate into AMPA. Furthermore, it can be used for contaminant source allocation and product authenticity as well.
    No preview · Article · Jan 2013 · Analytical and Bioanalytical Chemistry
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