A study of the halogenated organics derived from the chlorination of Humic acid in the presence of bromide was undertaken. The analysis involved liquid-liquid extraction with ether of the neutral (pH 7) and acidic (pH 1) fractions of the humic solution, followed by identification of the compounds by Gas Chromatography with Electron Capture (ECD), Microwave Induced Helium Plasma (single channel (MIP) and multichannel (MMIP)) and Mass Spectroscopy (MS). Amherst drinking water was also analyzed. Parameters of pH, Cl/Br ratio, and time were investigated in humic acid chlorination (with bromide) to determine effects upon Trihalomethane (THM) formation. The effect of chloramination upon THM study vs. chlorination was also examined. GC-MS was used to identify compounds formed from Humic acid and in tap water. Selected spectra and interpretations are included. Five halogenated compounds in water were identified using GC-MS. GC-MIP and GC-MMIP were used to identify halogenated compounds by monitoring chlorine, bromine and carbon emission lines singly and simultaneously. From this empirical formulae for halogenated compounds were deduced. From all of these methods over 15 halogenated compounds have been identified from the chlorination of Humic acid and ten of these have been found to occur in finished drinking water. They are: chloroform (100 ppb), bromodichloromethane (8 ppb), dichloroacetonitrile (4 ppb), chlorodibromomethane (1 ppb) and bromoform (2 ppb). Trichloroacetic acid (100 ppb), dichloroacetic acid (10 ppb) and chlorodibromoacetic acid (1 ppb) were found in the acidic fraction. Trichloroacetaldehyde and trichloroacetone were also found but not quantitated.

The wide application of the different inductively coupled plasma (ICP) techniques commonly available has demonstrated that these methods of excitation and analysis can be reliably used for qualitative and quantitative applications. The enclosed inductively coupled plasma (EICP) adds to the advantages of the conventional ICP some unique features, such as wide operation pressure range, low sample consumption, and capability for the analysis of reactive and/or highly toxic materials. The EICP can be used in two modes: sealed and flowing. In the sealed configuration the gas flow through the container is stopped after the plasma discharge is established, and the plasma is sustained with only the gas inside the container. None of the approaches previously available provided an accurate representation of experimental EICP discharges or used all the predictive capabilities that a modeling technique can give to the evaluation of a plasma discharge. Therefore, the comprehensive modeling of the EICP configuration through the adaptation of existing models and development of new approaches was undertaken as the main goal of the present work. Once the model was developed it was tested and applied to the characterization of different experimental conditions important to the study of the EICP and its possible applications and optimization.

In the area of biomolecular separations, capillary electrophoresis (CE) is advantageous in terms of analysis speed, peak efficiency and small sample size requirements. In order to more fully assess the capabilities and limitations of this bio-analytical technique, CE was applied to a clinical, to a biological and to a practical research problem. In the area of clinical analyses, CE was used to determine qualitatively and quantitatively oxalate in various parenteral nutrition solutions. It was hypothesized that parenteral nutrition solutions act as direct sources of oxalate introduction into premature infants. The formation of oxalate stones in the renal glands of premature infants is becoming an increasing apparent clinical problem. A coelectroosmotic CE analytical method based on indirect UV detection was developed that could reliably measure oxalate at part-per-million (ppm) levels in commercial parenteral nutrition solutions. The results from the oxalate determinations indicated that the infusion of parenteral nutrition solutions into premature infants places a clinically significant and unnecessary oxalate burden on the infants. The CE characterization of biosynthetic membrane protein samples is a formidable analytical task. This is mainly due to the fact that intrinsic membrane proteins are extremely hydrophobic, and thus, difficultly soluble in the common aqueous based CE run buffers. In this biologically oriented separation problem, a counterelectroosmotic CE method (CZE) was developed to characterize samples of the transmembrane serine receptor protein. Qualitative electrophoretic profiles of the protein samples were made possible by the inclusion of sodium dodecyl sulfate (SDS) in the run buffer. The utility of CE as a basic analytical technique was applied to the separation and determination of short-chain dicarboxylic acids (succinic, glutaric and adipic acids) in saturated aqueous solutions. In order to gather basic aqueous solubility data for a homologous series of dicarboxylic acids, a practical separation of succinic, glutaric and adipic acids was developed and optimized. The detection of the dicarboxylic acids was based on indirect UV absorbance. The solubility determinations for the dicarboxylic acids showed close agreement with the reported literature values.

As electronic cigarettes become more prevalent in society, their use as a delivery mechanism for drugs of abuse has increased. Electronic cigarette liquids present a complex matrix due to the lack of regulation, and therefore standardization, in their manufacturing. Due to the lack of published data, development of new analytical methods to accommodate this complexity was deemed necessary. Gas chromatography-mass spectrometry (GC/MS) and liquid chromatography-tandem mass spectrometry (LC/MS/MS) methods were developed to identify the flavorants of the electronic cigarette liquids as well as identify and quantify nicotine and common drugs of abuse used with these devices. Seven drugs of abuse were investigated: methamphetamine, heroin, cocaine, fentanyl, JWH-081, JWH-018, and AM-2201. Electronic cigarette liquids from five manufacturers were sampled. From each manufacturer five "flavors" of liquids were chosen. Each liquid "flavor" was tested at the manufactures reported nicotine concentrations of 0 mg/mL, 12 mg/mL, and 24 mg/mL to give a total of 75 electronic cigarette liquid samples. Liquid-liquid extraction was performed on all samples prior to analysis by GC/MS and LC/MS/MS. Analysis was performed in replicates of five to identify the electronic cigarette liquid components as well as quantify nicotine and the four analytes of interest. For any electronic cigarette liquid labeled as containing 0 mg/mL of nicotine in which nicotine was identified, the sample was analyzed by GC/MS to quantify the nicotine level. These concentrations were compared to the naturally occurring levels of nicotine found in certain food products. Identification of the flavorants of the electronic cigarette liquids as well as the quantitation of nicotine and the four commonly abused drugs was accomplished using GC/MS and LC/MS/MS. Samples of e-liquids labeled by the manufacturer as containing 0 mg/mL of nicotine may contain detectable and quantifiable levels of nicotine. Quantitation of drugs of abuse may be affected by matrix components and was found to be dependent on both the specific e-liquid being used with the electronic cigarette as well as the analyte being investigated.

Abstract not available

The development and evaluation of some new procedures for the determination of various chemical forms of aluminum, mercury, selenium, and sulfur are described in this dissertation. Studies of the biological and environmental transformations of elements are underpinned by the provision of reliable information about the relative concentrations of various chemical forms of the elements. Here, the final measurements were made by graphite furnace atomic absorption spectrometry (GFAAS), cold vapor atomic absorption spectrometry (CVAAS), molecular emission spectrometry (MES) and atomic fluorescence spectrometry (AFS). These measurement techniques were preceded by selective chemical reactions based on liquid-liquid extraction (LLE), chemical vapor generation (CVG) [in particular, hydride generation (HG)] and selective redox chemistry. For the selenium and sulfur speciation techniques, the atomic fluorescence instrument was adapted to monitor molecular sulfur emission and selenium fluorescence simultaneously through two of the instrument's channels. The analyte elements in a sodium tetrahydroborate matrix were merged with a hydrochloric acid stream in a flow-injection manifold, chemical vapor generation was used to introduce the analytes into an argon-hydrogen diffusion flame in the form of hydrogen selenide and hydrogen sulfide. A speciation procedure was developed based on the reactivity towards borohydride at low acid concentrations and the amalgam trapping of both mercury and methylmercury hydride. Spectroscopic discrimination between the methylmercury and inorganic mercury was made by using an amalgam trap. When the amalgam trap was bypassed, no signal for methylmercury was observed. This method was applied to the determination of inorganic and methylmercury in river water tap water, and urine matrices. Validation was performed by analysis of the standard reference materials TORT-2, DOLT-2 and DOMR-2 CRMs. An automated flow-injection approach for the speciation of aqueous aluminum species in waters is suggested. It is intended that the flow-injection manifold be used to identify three types of aluminum; acid reactive (Alr), labile monomeric (Ala) and nonlabile monomeric (Alo). Initial results have been obtained for flow-injection liquid-liquid extraction interfaced with GF-AAS. (Abstract shortened by UMI.)

Abstract not available

No description available.

No description available.

A method was developed for pre-concentration, speciation and determination of arsenic species (As(III), As(V), MMA and DMA) in various water samples by solid phase extraction flow injection hydride generation atomic absorption spectrometry (SPE-FI-HG-AAS). The packing materials used for SPE included strong cation-exchange and strong anion-exchange silica beads. The devised method was successfully applied to the quantification of arsenic species in the University of Massachusetts campus pond water. A new method was developed for the determination of methylation and reduction of arsenic species (As(III), As(V) and DMA) in Mueller-Hinton growth media by E. coli based on anion-exchange chromatography with post column hydride generation and inductively coupled plasma optical emission spectrometry (HPLC-HG-ICP-OES). The method was successfully applied to the determination of metabolism of arsenic by E. coli by analyzing the growth media and the cell extracts. The investigations suggested that E. coli did not methylate any of the arsenic species but simply reduced As(V) to As(III). The media created a “split peak” effect for DMA, resulting in shorter retention time for the majority of the bulk and longer retention time for the rest of the species. This effect is most likely due to the reaction of DMA with the protein present in the media, generating a positive complex, which resulted in the shifts in retention times. Although the presence of hydride generation help enhances the arsenic signal by almost 30 times, it also affects the intensities of each arsenic species differently, some, such as As(III), benefit from the reaction than others, such as As(V). The studies revealed that when measuring different arsenic species in the absence of hydride generation, the ICP-OES sensitivity is not the same for all. Results from t- and F-tests suggested that AsB, DMA and As(V) are statistically the same, whereas As(III) and MMA, which are statistically indistinguishable, are from a different distribution.