The 12th Workshop "Microchip Technologies in Analytical Chemistry" took place on March 23, 2007, at the Institute for Analytical Instrumentation RAS. The Workshop program included the following reports: 1. (Bio)sensors and nano-electrode systems. A.A. Karyakin (Moscow State University, Department of Chemistry). 2. DNA analysis in a microfluidic chip by the method of real-time polymerase chain reaction. М.V. Lavrova, М.А. Erkin, D.V. Novolozkii, M.N. Slyadnev (Saint-Petersburg State University, "Lumex Ltd", Saint-Petersburg). 3. Informative signals in microchip-based electrophoresis: mathematical models and estimates. L. Bulianitsa (Institute for Analytical Instrumentation RAS, Saint-Petersburg). 4. Electrokinetic flows in microfluidic devices. A.N. Tupik (Institute for Analytical Instrumentation RAS, Saint-Petersburg). The Workshop was conducted with participation of researchers and specialists of Moscow M.V. Lomonosov State University, Saint-Petersburg State University, Institute for Chemistry of Silicates RAS, A.F. Ioffe Physico-Technical Institute RAS, FSUC "D.V. Efremov Research Institute for Electro-Physical Instruments", "Lumex Ltd", and Institute for Analytical Instrumentation RAS. This section contains the Workshop proceedings rewritten by their authors in the form of papers and also original papers concerning the Workshop subject.

M.V. Lomonosov State University, Department of Chemistry, Moscow

The flow extraction of complex of Co with 2-nitroso-1-naphthol on the liquid—liquid interface of a water-toluene two-phase flow with thermal-lens detection was studied on a microchip with a complex-shape microchannel partially modified with ODS. The controllable range of flow rates of aqueous and organic phases for establishing a stable liquid—liquid interface and the optimum flow rates for carrying out the extraction processes (6 and 0.05 μl/min, respectively), were determined as well as optimum detection position in a microchannel. The method of the abruptly dropping flow rate of the organic phase (in initial flow rate of 5 l/min) to the optimum with a constant flow rate of aqueous phase was proposed in order to initiate the extraction processes through the liquid—liquid interface which resulted in the reduction of time of analysis and increase of the sensitivity and reproducibility of determination. The calibration for complex of Co showed good linearity in the range of concentrations of 2.0· 10^–7 – 8.0 · 10^–6 М with a limit of detection of 3 · 10^–8 М and the standard deviation in this range of no higher than 0.03.

*Department of Chemistry, M.V. Lomonosov Moscow State University **Japan Science and Technology Agency (JST), Honcho, Kawaguchi, Saitama, Japan ***Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Japan

The paper is devoted to optimization of a microfluidic analytical system (MFAS) designed to perform polymerase chain reaction (Real-Time PCR) in a glass-silicon microchip comprising 16 microreactors 1.3 l each. We have evaluated various methods of surface modification and proved that polymethylmethoxysiloxane-based polymeric coating (PMMS) is the best one to prevent PCR inhibition. Using the proposed modification technique, we succeeded in obtaining large water wetting angles on silicon surface and also in reducing considerably the time of preparing the microchip for the analysis. The estimates obtained show that the multi-reactor PCR MFAS provides DNA detection by the Real-Time PCR method with the efficiency equal to the theoretically possible level.

*Saint-Petersburg State University, Department of Chemistry **"Lumex Ltd", Saint-Petersburg

The paper concerns the optimization of conditions of Real-Time polymerase chain reaction (Real-Time PCR) taking place in a microfluidic analytical system. We have compared the methods for estimating the temperature inside the microreactors and proved that the contact method provides adequate estimates of temperature achieved inside the microfluidic chip microreactors. Optimization of the amplification regime has been carried out; it has been proved that reduction of the temperature duration at the termocycling stages allows one to decrease considerably the analysis time without losses in sensitivity and also without drastic reduction of the PCR efficiency. The paper demonstrates that the time necessary to pick up 5 copies of DNA molecules is 18 minutes only.

*Saint-Petersburg State University, Department of Сhemistry **2"Lumex Ltd", Saint-Petersburg

The paper considers possible lines of developing algorithms for processing and estimating analytical signals of microchip electrophoretic devices: simulation of informative signals (peaks) and non-informative components (base line drift and high-frequency noise). Based on the information obtained, sources of interference can be revealed, the optimal algorithms for the signal estimation have been found, and criteria for neighboring peaks separation have been modified. Efficiency of conventional economical methods for signal pre-processing, namely, trend compensation and a filtration, as well as validity of the new technique for peak area estimation and applicability of the main component method in multi-channel measurements when the peak boundaries can hardly be localized, have been shown for electrophoregramms obtained by separating the DNA fragment mix on a microfluidic chip.

Institute for Analytical Instrumentation RAS, Saint-Petersburg

The paper represents some experimental results on electroosmotic flows in microfluidic chips. We have found out that chemical and thermal processes taking place in microchip encapsulation affect the channel surface properties thus determining the electroosmotic flow mobility. It has been shown that the character of variations in the electroosmic flow rate depends on the plate surface treatment technique and materials the channeled and protective plates are made from.

Institute for Analytical Instrumentation RAS, Saint-Petersburg

The paper considers the NAA (Nuclear Acid Analyzer) thermal operating conditions. The dependence of voltage applied to the Peltie element and Real-Time PCR rate has been studied. The difference in temperatures of the tablet and reaction mix has been analyzed.

Institute for Analytical Instrumentation RAS, Saint-Petersburg

The goal of the paper is to study an ideal phase compensator with the Jones diagonal matrix. We have proposed a method of optical alignment that ensures, if the mechanism of spatial orientation is available, a conversion into the ideal compensator. Equations for complex parameter ρ (real parameters δ and f) that determines the ideal compensator Jones matrix have been derived. In this connection, a four-dimensional matrix of a homogeneous anisotropic layer for the case of arbitrary orientation of two main axes in the light ray plane of incidence has been analyzed. The paper considers methods for controlling the basic phase parameter δ, including those for temperature stabilization and varying this parameter by changing the light ray angle of incidence onto the compensator plate.

Institute of Applied Physics NAS, Ukraine, Sumy *Institute for Analytical Instrumentation RAS, Saint-Petersburg

The paper suggests an approach to calculation of characteristics of an ultrasonic resonance chamber consisting of a piezoelectric radiator and multi-layer liquid chamber adjacent, generally, to the liquid half-space. The method suggested allows one to get exhaustive information on intra-chamber physical processes. For instance, a non-loaded radiator and a radiator loaded with acoustic resistances with both constant and frequency-dependent impedances have been considered.

Institute for Analytical Instrumentation RAS, Saint-Petersburg

Time-frequency transformations (TFT) used in signal analysis can change their form and characteristics of two-dimensional representation of non-stationary signals at the given form of the so-called covariance that is the property of TFT form modification associated with time or frequency scaling of the signal under analysis. Extended interpretation of the covariance property manifests itself in modification of TFT representation analytical forms. The paper considers some elements of theoretical methods for obtaining various TFTs and the measure of their adaptation to the specificity of signal under analysis. The methods for constructing IMS non-stationary signal transformations have been generalized. The main TFT structures were represented earlier ("Nauchnoe priborostroenie", v. 12 (2, 3), 2002).

Saint-Petersburg

The device described applies to the field of instrument engineering, namely, to the methods for timing data detected in autonomous information-measuring systems (AIMS), e.g., in sea-bottom geophysical stations. The purpose of the work was to increase the accuracy of AIMS data timing at limited power consumption.

*Shirshov Oceanology Institute RAS, Moscow **Design Bureau of Oceanologic Equipment RAS, Moscow ***Moscow Engineering and Physical Institute