Simple concept of DLLME in universal DV-SIA system ? comparison of LLE and DLLME procedures for thiocyanate determination

HANA SKLENÁROVÁ; CAROLINA ACEBAL; JANA SKRLÍKOVÁ; VASIL ANDRUCH; IOSEPH BALOGH; PETR CHOCHOLOU; PETR SOLICH

Isla de Creta

Conferencia; 7th International Conference Instrumental Methods of Analysis-Modern Trends and Applications-IMA 2011; 2011

A micro-extraction based on a creation of dispersion (the dispersive liquid-liquid micro-extraction, DLLME) [1], which was introduced in 2006, was tested in the sequential injection system with two selection valves (DV-SIA system). The extraction process was based on the formation of a mixture of water-organic solvent (with higher density than water) and dispersion agent, which is miscible with water and is relatively polar. After a quick injection of this mixture into an aqueous solution of the substance a dispersion in the aqueous extraction phase (to create micro-drops) was obtained. This procedure created a large surface area - the inter-phase, leading to a great acceleration of the substance transfer from the aqueous into the organic phase (extraction). In batch conditions extraction step and separation of water and organic phases should be followed by off-line centrifugation. In the flow system the organic phase containing an analyte, which was at the bottom, was directly sampled for on-line detection. Testing DLLME procedure automation was carried out for thiocyanate extracted as a colored complex with astrafloxine created under acidic conditions (pH 3). The same determination was chosen for LLE automation in the DV-SIA system and thus both extraction processed were compared with respect of system design and its versatility, optimized conditions, calibration range, pre-concentration possibilities and sample throughput. This work has been supported by the Scientific Grant Agency of the Ministry of Education of the Slovak Republic and the Slovak Academy of Sciences VEGA (Grant No. 1/0226/11). C. Acebal has acknowledged financial support of her scholarship in research fellowship program between Ministries of Education of Argentina and the Czech Republic. References [1] M. Rezaee, Y. Assadi, M.-R. M. Hosseini, E. Aghaee, F. Ahmadi and S. Berijani, J. Chromatogr. A 1116 (2006) 1-9.