In the automation of sample dilution or derivatization, the performance of the mixing technique employed when adding solvents or reagents to samples is critical. This paper presents a newly developed mixing method, based on conventional aspiration and dispensing of liquid techniques, but which considerably improves the precision of mixing. The paper discusses the results of a comparison of the ...

The helix-to-coil denaturation transition in DNA has been investigated in mixed solvents at high concentration using ultraviolet light absorption spectroscopy and small-angle neutron scattering. Two solvents have been used: water and ethylene glycol. The "melting" transition temperature was found to be 94 degrees C for 4% mass fraction DNA/d-water and 38 degrees C for 4% mass fraction DNA/d-eth...

Highly effective mixing in microchannels is important for most chemical reactions conducted in microfluidic chips. To obtain a rigid and chemically resistant micromixer system at low cost, we fabricated a Y-shaped microchannel with built-in mixer structures by static liquid photolithography (SLP) from methacrylated polyvinylsilazane (MPVSZ) as an inorganic polymer photoresist which was then con...

Fifteen years ago, surface acoustic waves (SAW) were found to be able to drive fluids and numerous applications in microfluidics have been developed since. Here, we review the progress made and report on new approaches in setting-up microfluidic, continuous flow acoustic mixing. In a microchannel, chaotic advection is achieved by generation of a SAW driven fluid jet perpendicular to the mean fl...

It is known that ammonium azides are both effective and convenient azidation agents, which are widely used in the syntheses of tetrazoles in media of aprotic dipolar solvents. However, until the present time, information about using these reagents for the synthesis of the 1,2,3-triazoles has been absent. In this case, alkali metal azides as well as trimethylsilyzide are the best known azidation...

Deep eutectic solvents (DESs) are novel solvent media that are currently under investigation as an alternative to ionic liquids and conventional solvents. The physical properties of DESs as well as their mild environmental footprint and potentially critical industrial application necessitate understanding the interaction of functional groups on both the salt and hydrogen bond donor (HBD). In th...

Fecal lipid content is usually determined by titrimetric or gravimetric methods, but these methods are time consuming and involve dangerous solvents. We have developed a new method of measuring fecal lipids by Fourier transform infrared spectrometry (FTIR) with an attenuated total reflectance accessory that is fast and requires no solvents. The spectra of stools from 4000 to 750 cm-1 were analy...

Using nondegenerate two-wave mixing in colloidal suspensions we measure the viscosity of liquids with as little as 20 picoliters of volume. In addition, changes in the frequency signature with intensity are observed which are interpreted in terms of selffocusing effects. Typical viscosity measurements require volumes ranging from tens of milliliters to liters of liquid. For many applications in...

The author herein reviews a specific microfluidic behavior exhibited by mixed-solvent solutions in a microspace, coined as the tube radial distribution phenomenon (TRDP). The specific fluidic behavior was observed in the following solution systems: ternary water-hydrophilic/hydrophobic organic solvents, water-surfactant, water-ionic liquid, and fluorous/organic solvents. When the mixed homogene...