Stuart A. Oehrle

Controlled changes in selectivity of cation separations by capillary electrophoresis using various crown-ether additives

Abstract This paper investigates how the concentration and type of crown ether effects the separation of cations and how one can optimize the concentration of the crown ether the achieve the best separation. An electrolyte consisting of 1.0 m M UV Cat-2, 3.0 m M trupolone, and 3.5 m M 18-crown-6 was found to provide the best separation for all cations investigated. Use of this optimized electrolyte was applied to the analysis of low levels of potassium in technical grade ammonium tungstate used in the electronics industry.

Analysis of nerve agent degradation products using capillary ion electrophoresis

Abstract A method has been developed for the analysis of nerve agent degradation products using capillary ion electrophoresis. Analysis of the primary degradation products isopropyl methylphosphonic acid, ethyl methyl-phosphonic acid, pinacolyl methylphosphonic acid and methylphosphonic acid was accomplished with run times of less than 5 min. Detection of low mg/l levels of degradation products in spiked water samples was possible. Little sample preparation was required for the analysis of the alkyl methylphosphonic acids.

Environmental monitoring of wastewater using capillary ion electrophoresis

Capillary ion electrophoresis (CIE) is a capillary electrophoretic technique which has been developed for the rapid analysis of low-molecular-mass inorganic and organic ions. Anion and cation analysis of wastewater samples from a meat processing plant will be discussed. The wastewater samples were collected above, at point of discharge, and at various points downstream from the plant. The purpose of the analysis was to investigate dilution effects of the wastewater as it mixes with the stream water. CIE allows for rapid analysis times (typically less than 5 min) with little sample preparation required.

Analysis of nitramine and nitroaromatic explosives by capillary electrophoresis

Abstract Analysis of nitramine and nitroaramatic explosives is of interest for both environmental and forensic applications. Analysis of 14 nitramine and nitroaromatic explosives was accomplished by micellar electrokinetic capillary chromatography, MECC. Analysis times under 11 min were possible employing a phosphate-SDS electrolyte. Detection limits for each explosive at different wavelengths (185 nm, 214 nm, 229 nm and 254 nm) were calculated. Analysis of various extracts of high explosives such as composition C-4, tetrytol and detonating cord was performed. Detection limits less than 1 mg/L were possible using a hydrostatic injection and direct UV detection at 214 nm.

Analysis of low-level anions in water extracts of hard disk drive heads by capillary electrophoresis

Analysis of anionic contaminants in various electronic components is of importance in assessing cleanliness as well as in identifying contaminants in failed devices. Typically the levels of anionic contaminants is in the low μg/l range. Capillary electrophoresis (CE) is one technique that can be used to analyze these low level anions. Analysis of several water extracts of failed devices as well as various components of the drive head and assembly was done using CE with analysis times of less than 5 min. Two different concentrations and pH values of a chromate-based electrolyte were evaluated. Both electrolytes achieved detection limits of less than 1.2 μg/l using an electromigrative injection.

Determination of inorganic and organic ions in nickel-plating baths by capillary electrophoresis

Analysis of nickel-plating baths for various anions, organic acids and cations was performed by capillary electrophoresis. Analysis of these ions is important in relation to the effectiveness of the plating bath. Analysis of anions and organic acids in these plating baths was accomplished by direct UV detection at 185 nm and a phosphate electrolyte. Nickel and other cations were determined by indirect UV detection at 185 nm as well. Total analysis times of less that 7 min for anion and organic acid analysis and 5.5 min for nickel and other cations analysis could be achieved using these electrolytes. Changeover time from anion to cation analysis by capillary ion electrophoresis was accomplished in less than 10 min.

Analysis of ginkolides and biobalides by capillary electrophoresis

Abstract A method has been developed to analyze for biobalide, ginkolide A and ginkolide B by capillary electrophoresis (CE). Analysis was accomplished by using a phosphate and sodium dodecyl sulfate (SDS) buffer with direct UV detection at 185nm. Run times of less than eighteen minutes for the compounds of interest was possible.

Analysis of anionic impurities in ammonium dinitramide (ADN), Part I: Ion chromatographic analysis

Abstract A method has been developed to analyze ammonium dinitrimide, a new energetic material, as well as other anionic impurities in it. This method employs ion chromatography with UV detection. Analysis of ADN samples could be done in under 20 minutes employing this method. Analysis of pure samples as well as aged samples was accomplished.

Analysis of Stabilizer Degradation Products in Propellants Using HPLC and Photodiode Array(PDA) Detection

Analysis of stabilizer and stabilizer degradation products in nitrocellulose based propellants was done using high-performance liquid chromatography(HPLC) with photodiode array(PDA) detection. Analysis of these compounds was done in less than 12 minutes using an isocratic mobile phase. Using PDA detection provided the capability of monitoring at several different wavelengths as well as providing UV spectra which could be used to assess peak purity and match the spectra against known library spectra.

Analysis of CL-20 and TNAZ in the presence of other nitroaromatic and nitramine explosives using HPLC with photodiode array (PDA) detection

Abstract Several new explosives (CL-20 and TNAZ) have recently attracted attention as possible replacements for various explosive compounds. If these compounds become heavily used they may eventually come under regulation. A method for the analysis of CL-20 and TNAZ in the presence of 14 nitroaromatic and nitramine explosives and their degradation products currently included in EPA SW-846, Method 8330 has been developed using high performance liquid chromatography (HPLC). Photodiode array (PDA) detection was employed for peak identification and confirmation. Analysis times of less than 30 minutes was achieved using an isocratic HPLC mobile phase of water and isopropanol.