A simple spectrophotometric method based on the reaction with bromocresol green (BCG) has been developed for determination of total alkaloids in medicinal plants. A yellow complex forms and is easily extractable by chloroform at pH 4.7. The absorbance of the complex obeys Beerûs law over the concentration range of 4-13 μg atropine per ml of chloroform. This procedure can be carried out in the presence of other compounds without interference.

Spectrophotometric determination of total alkaloids in some iranian medicinal plants

Determination of theobromine, theophylline and caffeine in cocoa samples by a high-performance liquid chromatographic method with on-line sample cleanup in a switching-column system

Artificial high-intensity sweeteners are used increasingly frequently for food production. The food industry tends to highlight beneficial aspects of their use (e.g., tooth friendliness, increasing the quality of life of those suffering from different forms of diabetes and the possibility of weight control without anyone sacrificing their favorite “unhealthy” drinks or snacks). However, some consumers are deeply concerned about the safety of artificial sweeteners and claim that the food industry is replacing natural beet sugar or cane sugar for purely economic reasons. Most of these food additives have a maximum usable dose or a maximum allowable concentration specified for a given type of food. In order to assure consumer safety, it is necessary to control the content of sweeteners in foodstuffs. Analytical methods (including high-performance liquid chromatography, ion chromatography, thin-layer chromatography, gas chromatography, capillary electrophoresis, flow-injection analysis, electroanalysis and spectroscopy) can determine sweeteners individually and simultaneously in mixtures. This review focuses on the application of some popular analytical procedures for determination of artificial sweeteners in food.

Analytical methodologies for determination of artificial sweeteners in foodstuffs

A disposable, low-cost colorimetric sensor array has been created by pin-printing onto a hydrophilic membrane 16 chemically responsive nanoporous pigments that are comprised of indicators immobilized in an organically modified silane (ormosil). The array has been used to detect and identify 14 different natural and artificial sweeteners at millimolar concentrations, as well as commonly used individual-serving sweetener packets. The array has shown excellent reproducibility and long shelf life and has been optimized to work in the biological pH regime.

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Colorimetric detection and identification of natural and artificial sweeteners.

Separation and simultaneous determination of four artificial sweeteners in food and beverages by ion chromatography.

Simultaneous determination of artificial sweeteners, preservatives, caffeine, theobromine and theophylline in food and pharmaceutical preparations by ion chromatography.

Jing Wang

Papers

Simultaneous determination of artificial sweeteners, preservatives, caffeine, theobromine and theophylline in food and pharmaceutical preparations by ion chromatography.