Applicability of antimony film electrodes in anodic stripping voltammetry combined with sequential injection analysis

The possibilities to employ antimony-film plated glassy carbon electrode (SbFGCE) in anodic stripping voltammetry combined with sequential injection analysis(ASV-SIA) were examined and tested for the determination of Pb(II) and Cd(II) selected as the model ions. It has been found that SbF-GCE can be operated at the low :g l–1 concentration level via the in-situ preparation — deposition from a plating solution of 0.5 M HCl, mixed with 0.75 mg l–1 Sb(III), and at a potential of –1.5 V vs. Ag/AgCl. The same solution could then be used for pre-concentration and stripping, when the reproducibility of the respective signals was characterised 20 Guzsvány V. et al./Sci. Pap. Univ. Pardubice Ser. A 16 (2010) 19–31 by means of the RSD < 2.8 %, and the detection limit (3F) of about 1.2 μg l–1 Pb(II) and 1.4 μg l-–1 Cd(II). Furthermore, as found, the presence of weakly complexing halide salts, KCl or KBr, could further improve the overall signal-tonoise ratio, whereas the addition of KSCN into the solution(s) offered the possibility to detect some additional ions; namely, of highly electronegative metal elements such as Zn(II), Mn(II), and Cr(III)

Influence of structural dimensions of micro-pillar array in reaction field on sensitivity of enzyme-linked immunosorbent assay (ELISA)

For high sensitivity and rapid reaction of enzyme-linked immunosorbent assay (ELISA), the film-stack reaction field with micro-pillars array was designed and developed. The film-stack reaction field was fabricated by a nanoimprint process and an automatic punch-press process. The films with different gaps between micro-pillars (5, 10 and 50 μm) were prepared. These reaction fields were evaluated by IgA ELISA using 96-well microtitre plates and the computational simulation analysis of the fluid flow and the particle trajectory. Compared with ELISA using only the microtitre plate, higher detection sensitivity and shorter incubation time were achieved using the film-stack reaction field due to the increased surface area and the circulating flow through the space between films in a well by the rotation of the film-stack reaction field. Furthermore, in the ELISA results obtained using the film-stack reaction fields, the fluorescence intensities in 10-μm and 50-μm pillar gaps were the minimum and maximum values, respectively. This trend was due to the flow rate between micro-pillars, and the number and the diffusion distance of supplied biomolecules to the inertial space in the film-stack reaction field. In simulation results, the trend of the number of adsorbed biomolecule particles with different gaps between micro-pillars was in agreement with the trend in the ELISA results. Hence, these simulation analyses were validated in the quantitative evaluation of this reaction field and could be applied in the design of this reaction field as an effective design tool

Rapid ELISA Using a Film-Stack Reaction Field with Micropillar Arrays

A film-stack reaction field with a micropillar array using a motor stirrer was developed for the high sensitivity and rapid enzyme-linked immunosorbent assay (ELISA) reaction. The effects of the incubation time of a protein (30 s, 5 min, and 10 min) on the fluorescence intensity in ELISAs were investigated using a reaction field with different micropillar array dimensions (5-µm, 10-µm and 50-µm gaps between the micropillars). The difference in fluorescence intensity between the well with the reaction field of 50-µm gap for the incubation time of 30 s and the well without the reaction field with for incubation time of 10 min was 6%. The trend of the fluorescence intensity in the gap between the micro pillars in the film-stack reaction field was different between the short incubation time and the long incubation time. The theoretical analysis of the physical parameters related with the biomolecule transport indicated that the reaction efficiency defined in this study was the dominant factor determining the fluorescence intensity for the short incubation time, whereas the volumetric rate of the circulating flow through the space between films and the specific surface area were the dominant factors for the long incubation time

Development of a Novel Two Dimensional Surface Plasmon Resonance Sensor Using Multiplied Beam Splitting Optics

sensor

Droplet Enhanced Fluorescence for Ultrasensitive Detection Using Inkjet

A fluorescence enhanced phenomenon was found within a micrometer-sized liquid droplet, and it was adopted to construct droplet enhanced fluorescence (DEF) for ultrasensitive fluorescence detection. In this paper, an inkjet was utilized to eject perfect spherical droplets to construct a microspherical resonator and to develop a DEF system. It was utilized to implement ultrasensitive fluorescence detection in a liquid specimen with a volume of several microliters. The DEF detection of fluorescent molecules, fluorescein sodium, was used as a model to validate the proposed enhanced fluorescence detection method. A low limit of detection (LOD) for fluorescein sodium of 124 pM was obtained. The sensitive detection of single stranded DNA (ssDNA) was experimentally completed, with a wide range of linearity with a LOD of 312 pM. The proposed mechanism can be used as an ultrasensitive detection technique for analyzing microliters of liquid samples

Inkjet Printing Based Separation of Mammalian Cells by Capillary Electrophoresis

This study describes a method to investigate the separation of cells by capillary electrophoresis (CE) coupled with inkjet printing system. The results validated the feasibility of inkjet printing for mammalian cells to achieve the drop-on-demand and convenient sampling into capillary then zone electrophoresis was applied to separate different cells according to their electrophoretic mobility, finally the peak signal were measured by UV detector. Linear relationship between the peak area and the droplet number was obtained within the range of 25–400 drops (<i>R</i>² = 0.996) at a fixed cell concentration 10⁶/mL, indicating that this system could be used for rapid and accurate quantification of cells