24: IMPROVING EFFICIENCY IN THE ANALYTICAL CHEMISTRY LABORATORY
Description: Analytical chemistry techniques are used in a variety of applications to support DOE missions. For example, chemical separations and detection methods are used for nuclear forensics and other applications to analyze a variety of environmental sample types for both stable and radioactive isotopes that span almost the entire periodic table. These analyses typically include dissolving the sample, isolating several chemical species of interest at relatively low concentrations, and then using a variety of different detection techniques. Efficiency of the analytical techniques is crucial to ensure the overall analysis process is timely, reproducible, and non-labor intensive.
Within the DOE and throughout numerous industries, the process of performing chemical analysis is based on traditional procedures that involve complex acid digestion of solid samples before measuring elemental and-or isotopic composition. These procedures are laborious, hazardous to personnel, generate waste products, and can require days to months before providing results. A transformational enabling technology is required that can provide real-time trace elemental and isotopic analysis without needing consumables or generating waste products and without the need for a man-in-the-loop specialized operator. Such a technology would address critical needs within the NNSA for nuclear forensics, uranium and plutonium detection, and other hazardous materials identification applications.
b: Preparation of Reproducibly Packed Large Capacity HPIC Columns
Description: High performance ion chromatography (HPIC) can facilitate high resolution and high efficiency separations for many analytes of interest but can be adversely affected by the relatively large quantities of mass commonly found in environmental samples. Large separation columns capable of handling mass loadings of 20 50 g total material are needed to allow HPIC separation of environmental-type samples. Currently, pre-packed HPIC columns suitable for analyzing samples at these mass levels are not commercially available. A commercial process could ensure the columns are more consistently and reproducibly prepared rather than the more inconsistent process of preparing these in the laboratory by hand. Columns using both cation exchange resin as well as anion exchange resin are needed. In order to achieve optimal resolution, small particle sizes are desired that complement the capabilities of HPIC. The columns should be able to flow at a rate of 0.5 to 1.2 mL-min at pressures less than 2000 psi to avoid excessive band broadening due to diffusion.
c: Tools to Automate Routine, Time-Consuming Steps in the Analytical Chemistry Laboratory
Description: Many of the major time intensive steps in analytical chemistry procedures are very simple, routine steps that potentially could be automated. For example, when performing a series of chemical separation steps, often the matrix of the sample needs to be changed at the end of one separation before a sequential separation is performed. This matrix change typically involves evaporating the excess solution the sample is in to near dryness and then reconstituting the sample in a new solvent matrix. This evaporation is done under controlled conditions because of the need to carefully ensure the solvent is fully evaporated while the solute product of interest is not destroyed by overheating. An automated dry-down instrument would be very useful for this process to increase efficiency. Such a system would need to be compatible with various acid vapors (specifically to include HNO3, HCl, HF, and HClO4). Important features are the sample throughput and routing of off-gases so as to be able to process large numbers of samples (e.g., as many as 24, each of volume 0.1-10 milliliters) without cross contamination between them. Many of the principles needed for successful implementation of an automated evaporator are laid out in the patents referenced below. Altering these concepts for use with materials with high acid concentrations are needed. For example, to our knowledge no current commercial systems can use perchloric acid (HClO4).
d: Preparation of High Purity Methanol or Other Reagents
Description: For some radiochemical processes, currently available reagents contain impurities that interfere with low level analyses. For example, analytes of interest have been found in commercial methanol reagents, causing an increase in the analytical background. Reagents must then first be distilled to remove impurities prior to analysis, greatly increasing analysis times. Acetonitrile is another example of a reagent that is needed at ultra-high purity for analytical chemistry. Commercially available ultra-high purity reagents in containers of appropriated material (e.g. Teflon) would eliminate these time consuming steps and improve the overall efficiency of the process.
Description: In addition to the specific subtopics listed above, the Department invites grant applications in other areas that fall within the scope of the topic description above.