CATECHOLAMINES AND RELATED COMPOUNDS SEPARATION ON A MIXED MODE COLUMN SEPARATION DE CATECHOLAMINES ET MOLECULES APPARENTEES SUR UNE COLONNE EN MODE MIXTE

The present paper presents the evaluation of a mixed mode column (reversed phase and cation exchange) performance for the separation of 12 catecholamines, indolamines and their precursors and metabolites. The influence of different parameters, like organic modifier nature and percentage, salts nature and percentage, on the compounds separation was investigated. Good separation of the 12 selected compounds was obtained in the isocratic mode using a mobile phase composed of 90 % methanol and 10% ammonium acetate 20 mM, however the analysis time was excessively long (80 minutes). Thus an elution gradient was optimized and it reduced the analysis time to less than half (35 minutes)

OPTIMIZATION OF A HPLC ANALYSIS METHOD FOR TAURINE AND CAFFEINE IN ENERGY DRINKS

This paper presents the optimization of a rapid, inexpensive, reliable and selective isocratic high performance liquid chromatographic (HPLC) method for the simultaneous determination of caffeine and taurine in energy drinks with two common detectors in series: evaporating light scattering detector (ELSD) and an ultraviolet (UV) detector. Satisfactory analysis results were obtained on an Astec apHera NH2 column using methanol/water (30:70 v/v) as mobile phase. The optimized method was used for the analysis of commercial energy drinks containing large amounts of carbohydrates (100 g·L-1) and considerably lower amounts of taurine and caffeine (4 and 0.6 g·L-1, respectively). The advantages of this method consist of its lack of preliminary samples treatment and also the fact that basic LC instrumentation was employed