Influence of the surfactant bromide of cetyltrimetyl ammonium in the determination of chlorogenic acid in instant coffee and mate tea samples.
In this study, two quantitative differential-pulse polarography (DPP) and square-wave voltammetry (SWV) methods were developed to determine total chlorogenic acid (CGA). Studies on this compound involve its reduction at a hanging mercury drop electrode in micellar media-a simple, fast, reliable, and sensitive method. The use of surfactant cationic cetyltrimethylammonium bromide (CTAB) was pivotal to the development of these methods, allowing for satisfactory changes in CGA reduction. The supporting electrolyte which provided the best-defined CGA determination was 0.04-mol L(-1) phosphate buffer at pH 6.0 in the presence of CTAB. Based on this use and under optimized conditions, the two new DPP and SWV methods for CGA analysis had detection limits of 2.36 x 10(-7) and 1.34 x 10(-9)mol L(-1), respectively, for a pure standard. Analysis of the standard in the presence of treated instant coffee and mate tea samples allowed for good average recovery rates, ranging from 97.06% to 105.90%.
de Araújo
Tatiane Alfonso
TA
Departamento de Química, CCET, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS 79070-900, Brazil.
Cardoso
Juliano Carvalho
JC
Barbosa
Antonio Marcos Jacques
AM
Ferreira
Valdir Souza
VS
D001965:Bromides / Q000737:chemistry*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry*; D002726:Chlorogenic Acid / Q000032:analysis* / Q000737:chemistry; D003069:Coffee / Q000737:chemistry*; D055664:Electrochemical Techniques; D004573:Electrolytes; D006863:Hydrogen-Ion Concentration; D013501:Surface-Active Agents / Q000737:chemistry*; D013662:Tea / Q000737:chemistry*
D001965:Bromides; D002593:Cetrimonium Compounds; D003069:Coffee; D004573:Electrolytes; D013501:Surface-Active Agents; D013662:Tea; D002726:Chlorogenic Acid; D000077286:Cetrimonium