This Small Business Technology Transfer (STTR) Phase I research project will encompass the design, fabrication and testing of prototypes for a new mass and heat flow transducer that would permit accurate measurements of solids, liquids and absorbed gases at nanogram and sub-nanogram levels. The development of a versatile and accurate mass sensor will enable the subsequent development of commercial instruments with the capabilities to quantitatively determine masses of solids, liquids, residues and absorbed/ adsorbed gases to less than one nanogram (nanobalance) and monitor mass changes and other properties during reactions with gases or as a function of temperature, humidity and other environmental factors (nanobalance /microcalorimeter). The sensitivity of commercial analytical balances is presently limited to greater than one micro-gram. The goal of this project is to develop a sensor by modifying the size and shape of the electrodes and by confining liquids, such as a drop of solution containing an analyte of interest, to a region of constant mass sensitivity by physical and/or chemical modifications of the electrode surface. The resulting sensor would enable nanogram measurements on a broad range of materials.
The redesigned quartz crystal resonator will increase sensitivity for analytical balances by at least two orders of magnitude, particularly for micro-balances, the fastest growing segment of the balance market. It will also greatly expand the types of materials and applications for simultaneous gravimetric/calorimetric analysis in nanogram quantities. One application of great commercial interest is the creation of a "droplet gravimeter", a new technique which measures the concentration of total dissolved solids in a drop of solution. The droplet gravimeter will measure the nonvolatile residue of the solution with parts-per-million precision after the solvent of determined mass is evaporated to dryness. For other poorly soluble but valuable materials such as synthetic proteins or DNA fragments, current limitations preclude using gravimetry routinely, and other less direct and more complex methods are required to determine solubility.
