Automated on-line dispersive liquid-liquid microextraction based on a sequential injection system

• Autores: Andruch, Vasil; Acebal, Carolina Cecilia; Škrlíková, Jana; Sklenářová, Hana; Solich, Petr; Balogh, Ioseph S.; Billes, Ferenc; Kocúrová, Lívia
• Año de publicación: 2012
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: SEQUENTIAL INJECTION-DISPERSIVE LIQUID-LIQUID MICROEXTRACTION (SI-DLLME); THIOCYANATE; UV-VIS SPECTROPHOTOMETRY
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

A novel approach for sequential injection-dispersive liquid-liquid microextraction (SI-DLLME) has been suggested. The method is based on the aspiration and mixing of a sample and all required aqueous reagents in the holding coil of an SIA system, delivering it into a conical tube and adding in a mixture of extraction solvent, auxiliary solvent and disperser solvent at high flow rate, resulting in the formation of a cloudy state and the extraction of an analyte. The mixture of extraction and auxiliary solvent is immiscible with water and has a density significantly higher than that of water; consequently, the resulting fine droplets in the mixture, which contain the extracted analyte, are self-sedimented in a short time at the bottom of conical tube. Thus, no centrifugation and no use of a microcolumn are required for separation of the extraction phase. Afterwards, the extracted analyte is aspirated and transferred to a micro-volume Z-flow cell, and the absorbance is measured.The performance of the suggested approach is demonstrated by the SI-DLLME of thiocyanate ions in the form of ion associate with dimethylindocarbocyanine reagent, followed by spectrophotometric detection. A mixture of amyl acetate (as extraction solvent), tetrachloromethane (as auxiliary solvent) and acetonitrile (as disperser solvent) was selected for the DLLME procedure. The appropriate experimental conditions for conventional DLLME and automated SI-DLLME were investigated. The analytical performance of both these procedures was compared. The absorbance of the colored extracts at wavelength 555nm obeys Beer's law in the range of 3.13-28.2 for conventional DLLME and 0.29-5.81mgL-1 of SCN for SI-DLLME, and the limit of detection, calculated from a blank test based on 3s, is 0.110 for conventional DLLME and 0.017mgL-1 for SI-DLLME.
Fil: Andruch, Vasil. Pavol Jozef Šafárik University; Eslovaquia
Fil: Acebal, Carolina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina
Fil: Škrlíková, Jana. Pavol Jozef Šafárik University; Eslovaquia
Fil: Sklenářová, Hana. Charles University; República Checa
Fil: Solich, Petr. Charles University; República Checa
Fil: Balogh, Ioseph S.. College of Nyíregyháza; Hungría
Fil: Billes, Ferenc. Budapest University of Technology and Economics; Hungría
Fil: Kocúrová, Lívia. Pavol Jozef Šafárik University; Eslovaquia