This thesis describes the design and development of novel micro analytical devices for application in on-line process analytics. The work describes the design, development, numerical simulation and application of these devices for two specific cases: (i) electrochemical detection of bio(chemical) species at micro-scale and (ii) separation and purification of biological reagents using immobilised metal affinity chromatography at micro-litre scale.

Chapter 1 provides a general overview and background to the field of process analytics, microreactors and theory related to the mass transfer inside the electrochemical microfluidic devices and meso-chromatography columns. Chapter 2 provides an overview of microfabrication methods and the numerical simulations employed for the development of micro analytical devices used in this thesis. Chapter 3 describes an experimental voltammetric study of enzyme cofactors in batch and hydrodynamic systems and also provides a numerical investigation of mass transfer over electrodes inside microreactors. Chapter 4 investigates the effect of hydrodynamic focusing within a microfluidic device in detail, using experimental and numerical techniques. The quantification of the results was carried out using a pseudo two-dimensional, steady state backward implicit finite difference model. A series of studies, interrogating the effects of volumetric flow rate, volume ratio and lead-in length, were carried out to quantitatively investigate hydrodynamic focusing. Chapter 5 details the development and fabrication of patterned photopolymerised and electrochemically polymerised (conducting) monoliths with dimensions in the range of 100-1000μm. The photopolymerised monoliths were characterised using hydrodynamic methods in order to study the flow profile. Electrochemical techniques were used to characterise the conducting monoliths and its composites, using N,N,N’,N’-tetramethyl-p-phenylenediamine. Chapter 6 describes an application of the photopatterned monoliths. A meso-chromatography column was fabricated and immobilised metal affinity chromatography at meso and micro-litre scale was studied inside these columns. Proteins with polyhistidine tags were shown to be successfully separated, purified and quantified under batch and hydrodynamic conditions.