Labeling caffeine content

Example The B E = const, linked scan [93] has been employed to quantify the caffeine content of coffee, black tea, and caffeinated cola softdrinks. [99] Caffeine, M" = 194, was determined by spiking the sample with a known concentration of [D3]caffeine, = 197, as internal standard. Both molecular ions dissociate to form a fragment ion at m/z 109 which was selected as m2. Then, the precursor ion scan showed either molecular ion, mi and [D3]mi, as precursor of the ion at m/z 109. The ratio of peak intensities was taken as a measure for the relative concentration of analyte and labeled standard (Fig. 4.29). 

Chou K-H, and BeU LN, Caffeine content of prepackaged national-brand and private-label carbonated beverages, J. Food Sci. 2007 72 C337-C342. 

In the production of food, caffeine and quinine maybe used directly or as components of flavourings. Their amount was limited in the past, but according to new legislation (see Section 10.3.3.1.8) only beverages that contain caffeine concentration higher than 150 mg/1 must be labelled as having High caffeine content . The maximum content of quinine in bitter drinks is not limited either. Sucrose octaacetate has been approved by the FDA as a food additive in the US, but not in the EU, where it may be added to foods only in the specified quantities. 

Ephedra was also sold in combination with many other herbs in obscure combinations. Labels frequently listed 10 or 15 different herbs, but, analysis usually disclosed only the ephedra alkaloids and caffeine as present in sufficient quantities to be physiologically active. After several well-publicized accidental deaths, products clearly intended for abuse, such as herbal ecstasy, and other look-alike drugs (products usually containing ephedrine or phenylpropanolamine designed to look like illicit methamphetamine, but in concentrations higher than recommended by industry or the FDA) were withdrawn from the market. Labels on these products were frequently misleading. For example, one might suppose that a product called Ephedrine 60 contained 60 mg of ephedrine when, in fact, the actual ephedrine content was 25 mg. 

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