Miniaturized, portable instrumentation has been gaining popularity in all areas of analytical chemistry. Capillary electrophoresis (CE), due to its main strengths of high separation efficiency, relatively short analysis time and low consumption of chemicals, is a particularly suitable technique for use in portable analytical instrumentation. In line with the general trend in miniaturization in chemistry utilizing microfluidic chips, the main thrust of portable CE (P-CE) systems development is towards chip-based miniaturized CE. Despite this, capillary-based (non-chip) P-CE systems have certain unmatched advantages, especially in the relative simplicity of the regular cylindrical geometry of the CE capillary, maximal volume-to-surface ratio, no need to design and to fabricate a chip, the low costs of capillary compared to chip, and better performance with some detection techniques. This review presents an overview of the state of the art of P-CE and literature relevant to future developments. We pay particular attention to the development and the potential of miniaturization of functional parts for P-CE. These include components related to sample introduction, separation and detection, which are the key elements in P-CE design. The future of P-CE may be in relatively simple, rugged designs (e.g., using a short piece of capillary fixed to a chip-sized platform on which injection and detection parts can be mounted). Electrochemical detection is well suited for miniaturization, so is probably the most suitable detection technique for P-CE, but optical detection is gaining interest, especially due to miniaturized light sources (e.g., light-emitting diodes).

Understanding the flow fields at the micro-scale is key to developing methods of success-fully mixing fluids for micro-scale applications. This paper investigates flow characteristics and mixing efficiency of three different geometries in micro-channels. The geometries of these channels were rectangular with a dimension of; 300 m wide, 100 m deep and 50 mm long. In first channel there was no obstacle and in the second channel there were rectangular blocks of dimension 300 m long and 150 m wide are placed in the flow fields with every 300 m distance attaching along the channel wall. In the third geometry, there were 100 m wide fins with 150° angle which were placed at a distance of 500 m apart from each other attached with the wall along the 50 mm channel. Fluent software of Com-putational Fluid Dynamics (CFD) was used to investigate the flow characteristics within these microfluidic model for three different geometries. A species 2D model was created for three geometries and simulations were run in order to investigate the mixing behaviour of two different fluid with viscosity of water (1 mPa s). Models were only built to investigate the effect of geometry, therefore only one fluid with similar viscosity was used in these models. Velocity vector plots were used in the CFD analysis to visualise the fluid flow path. Mass fractions of fluid were used to analyse the mixing efficiency. Two different col-ours for water were used to simulate the effect of two different fluids. The results showed that the mixing behaviour strongly depended on the channel geometry when other parameters such as fluid inlet velocity, viscosity and pressure of fluids were kept constant. In two geometries lateral pressure and swirling vortexes were developed which provided better mixing results. Creation of swirling vortexes increased diffusion gradients which enhanced diffusive mixing.

Carbon nanostructures in various forms and sizes, and with different speciation properties have been prepared from graphite by Liquid Phase -Pulsed Laser Ablation (LP-PLA) using a high frequency Nd:YAG laser. High energy densities and pulse repetition frequencies of up to 10 kHz were used in this ablation process to produce carbon nanomaterials with unique chemical structures. Dynamic Light Scattering (DLS), micro-Raman and High-Resolution Transmission Electron Microscopy (HRTEM) were used to confirm the size distribution, morphology, chemical bonding, and crystallinity of these nanostructures. This article demonstrates how the fabrication process affects measured characteristics of the produced carbon nanomaterials. The obtained particle properties have potential use for various applications including biochemical speciation applications.

Numerical simulations of light propagation through capillaries have been reported to a limited extent in the literature for uses such as flow-cell design. These have been restricted to prediction of light path for very specific cases to date. In this paper, a new numerical model of light propagation through multi-walled cylindrical systems, to represent coated and uncoated capillaries is presented. This model allows for light ray paths and light intensity distribution within the capillary to be predicted. Macro-scale (using PMMA and PC cylinders) and micro-scale (using PTFE coated fused silica capillaries) experiments were conducted to validate the model's accuracy. These experimental validations have shown encouragingly good agreement between theoretical predictions and measured results, which could allow for optimisation of associated regions for monolith synthesis and use in fluidic chromatography, optical detection systems and flow cells for capillary electrophoresis and flow injection analysis.

Metal nanoparticles have unique chemical, physical, electrical, and optical properties that make them attractive for a wide range of applications in sensing, anti-fouling surfaces, medicine, and conductive inks. Pulsed Laser Ablation in Liquid (PLAL) is a green method of nanoparticle colloid production, capable of producing ligand-free nanoparticles in solution without the need for hazardous, environmentally unfriendly chemicals. Control of the process parameters can give control over the resulting colloid properties such as particle size distribution. In this work, silver (Ag) nanoparticles (NPs) with average particle size from 2.04 to 19.3 nm and copper (Cu) NPs with average particle size from 40 to 85.9 nm were produced by PLAL) technique.