Liquid-handling system

Automation using a robotic liquid handling system eliminated most of the tedious steps encountered with traditional manual extraction procedures. Automated 96-well SPE and LLE techniques using robotic liquid handlers have been successfully implemented to support high-throughput bioanalysis.5... 

Typical protein precipitation procedures use one volume of plasma plus three to six volumes of acetonitrile or methanol (or a mixture) with the internal standard at an appropriate concentration for the assay. Poison et al.102 reported that protein precipitation using acetonitrile eliminates at least 95% of the proteins after filtration or centrifugation, the supernatant can often be directly injected into the HPLC/MS/MS system. Usually this step is performed using 96-well plates that are ideal for semi-automation of sample preparation. Briem et al.103 reported on a robotic sample preparation system for plasma based on a protein precipitation step and a robotic liquid handling system that increased throughput by a factor of four compared to a manual system. 

FIGURE 4 Pipetting devices Eppendorf pipettes, Eppendorf EDOS 5222 electronic dispensing system, PerkinElmer Packard MultiProbe II EX and Tomtec Quadra 3 96-well plate liquid handling system. 

Salts of a substrate having an acid or an amine functionality are prepared by dissolving the substrate and the counter-base (or acid) separately in appropriate solvents, mixing the two solutions in equimolar ratios, and removing the solvents under vacuum to afford a solid. This method has two distinct advantages First, the composition of the substrate remains the same during various crystallization attempts, and second, this portion of the work can be automated with the use of liquid handling systems. 

The next step is to determine the solubility of the substrate (or its salts) in different solvents. This can also be performed by an automated liquid handling system. Depending upon the solubility of the substrate in water-miscible solvent (alcohols, acetone, tetrahydrofuran, etc.) and water-immiscible solvents (ethyl acetate, methyl-tert-butyl ether, heptane, etc.) the process chemist can identify one or many solvent systems from which the substrate (or its salts) could be ciystallized using the antisolvent addition strategy. 

The polymerization mixtures consisting of EtOx, SoyOx, methyl tosylate, and acetonitrile were automatically prepared utilizing the liquid handling system of... 

The siRNA libraries are obtained as a 10 pM stock and we prepare a 1 30 dilution resulting in 333 nM daughter plate concentrations. Although this step can be done manually using multichannel pipets, it can be greatly expedited by the use of a liquid-handling system, such as the Biomek EX Workstation (Beckman Coulter Brea, CA). 

Thermo Fisher Scientific, USA (formerly Fisher Scientific and Thermo Electron). The number one company in this field [sales > 9 billion (2007,E)] supplies biochemicals and bioreagents organic and inorganic chemicals (of which >15,000 fine organic chemicals) sera cell culture media sterile liquid-handling systems microbiology media and related products scientific consumable products, instruments, and equipment. 

Moser, I., Jobst, G., Svasek, P., Varahram, M., Urban, G., Rapid liver enzyme assay with miniaturized liquid handling system comprising thin film biosensor array. Sensors Actuators B. 1997, 44, 377-380. 

In order to achieve high throughput with ORAC determinations, Huang et al.464 have developed a robotic eight-channel liquid handling system coupled with a microplate fluorescence reader, which has improved efficiency at least 10-fold, compared with the discontinued COB AS FARAII analyser. The CV was 15% or less and the limits of detection and quantification were 5 and 6.25, uM, respectively. 

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