A flow method based on solvent extraction coupled on-line to a reversed micellar mediated chemiluminescence detection for selective determination of gold(III) and gallium(III) in water and industrial samples

Flow-Injection Chemiluminescence Method for Sensitive Determination of Ascorbic Acid in Fruit Juices and Pharmaceutical Samples Using a Luminol-Cetyltrimethylammonium Chloride Reversed Micelle System

“…1). [20][21][22] The flow system was comprised of an FI analyzer (Model K-1000, Hitachi, Tokyo, Japan) equipped with a 16-port rotary programmed automatic injection valve, a computer-controlled pump unit (Model CCPD, Tosoh, Tokyo, Japan), an isocratic pump (Nihon DIONEX, Osaka, Japan), and a photometer (Model LF-800, Niti-on, Funahashi, Japan) with a spiral flow cell (70 mm 3 ). An extraction coil (0.5 mm i.d., 4.0 m length) and a phase separator with a Teflon membrane (thickness of 60 μm, pore size of 0.22 μm, and a 40-mm 2 surface area: 2 mm width × 20 mm length), available as additions with Hitachi Model K-1000 FI analyzer, were used for the extraction and phase separation purposes.…”

“…At the phase separator, the Teflon membrane was permeable to the organic phase alone and 95% of toluene separated from water was sent onward to a 70-μL spiral flow cell of the detector. 20 The reversed micellar luminol reagent, after being sucked with a peristaltic pump into a loop of 100 μL, was inserted into the carrier stream of toluene using an automated rotary injection valve. The carrier stream was driven at a flow rate of 1.5 mL min -1 .…”

“…In the aforementioned process (2) of the on-line extraction, the correlation between the ion-pair extractability and the HCl concentration in the aqueous Au(III) solution is immensely important. 20 Figure 2 reveals the changes in the CL intensities obtained for Au(III) as a function of the HCl concentration in the 3.0 × 10 -7 M Au(III) aqueous solution containing 5.0 × 10 -5 M RB. With an increasing amount of HCl in the aqueous solution of Au(III), the CL intensity became enhanced initially and reached a maximum at near 2.0 M HCl, which was thus considered to be the optimum concentration of the acid.…”

“…Beyond this maximum limit, the CL intensity decreased, suggesting the suppression of the ion-pair formation of [AuCl4]with RBH + . 20 This trend for the dependence of CL intensity on the HCl concentration is similar to that reported previously for an on-line extraction-CL procedure where the RMM-CL reaction of RB with Ce(IV) was employed, 20 implying that the RMM-CL detection based on the luminol-Au(III) reaction, used instead of the RB-Ce(IV) reaction, is similarly available for the combination of CL detection with the extraction system of Au(III) with RB. The RB concentration was also optimized in a similar manner and it was found to be 5.0 × 10 -5 M. RMM-CL reaction of luminol.…”

“…18 With a view to enhancing the selectivity of CL methods used for practicable FIA, hybrid FI methods based on coupling of CL detection with liquid-liquid extraction have been further developed using reverse micelles as microreactors in the CL systems. [18][19][20][21][22] The center of the reversed micellar core (i.e. water pool) is filled with water molecules; while the hydrophobic chains of surfactant molecules extend into the bulk organic solvent, their polar groups are concentrated in the water pool, 23 where CL oxidation occurs.…”