Determination of cadmium and lead at sub-ppt level in soft drinks: An efficient combination between dispersive liquid-liquid microextraction and graphite furnace atomic absorption spectrometry

• Published in: Food chemistry Vol. 221; pp. 907 - 912
• Main Authors: Mandlate, Jaime S., Soares, Bruno M., Seeger, Tassia S., Vecchia, Paula Dalla, Mello, Paola A., Flores, Erico M.M., Duarte, Fabio A.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15-04-2017
• Subjects: Cadmium - analysis; Cadmium - isolation & purification; Cadmium determination; Carbonated Beverages - analysis; Dispersive liquid-liquid microextraction; Food Contamination - analysis; Graphite; Graphite furnace atomic absorption spectrometry; Lead determination; Limit of Detection; Liquid Phase Microextraction - methods; Soft drinks; Spectrophotometry, Atomic - methods; Dispersive liquid-liquid microextraction; Graphite furnace atomic absorption spectrometry; Cadmium determination; Lead determination; Soft drinks
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2016.11.075

•Determination of low levels of Cd and Pb by GF AAS in soft drinks.•Simple extraction and pre-concentration steps of Cd and Pb employing DLLME.•Fast extraction and high efficiency with good enrichment factors.•Feasible and simple method for Cd and Pb determination in soft drinks.•Extremely low limits of detection and good accuracy were achieved.
A DLLME method for extraction and preconcentration of Cd and Pb from soft drinks and further determination by GF AAS was developed. Important parameters of DLLME such as the type and volume of dispersive and extraction solvents, concentration of DDTC (complexing agent) and pH were evaluated. Better results were obtained using 500μL of acetone for Cd and 700μL of acetonitrile for Pb as dispersive solvents, 60μL of CCl4 as extraction solvent for both analytes and 500μL of 1.5% DDTC solution. Accuracy was evaluated by recovery assays and ranged from 91 to 113% for Cd and from 95 to 108% for Pb, with RSD below 10 and 7%, respectively. The LODs were 0.006 and 0.072ngL−1 for Cd and Pb, respectively. The optimized method was applied for the determination of Cd and Pb in soft drinks with different brands and flavours.