The performance of a Hewlett Packard Particle Beam LC/MS interface is evaluated using EPA appendix VIII and IX compounds. The behavior of these priority pollutants in the interface could determine its feasibility as a future EPA certified technique. The evaluation process consists of studies to determine minimum detectable quantities (MDQ), linear response, and band broadening contributions. The MDQ's of the analytes in electron impact and chemical ionization modes are extrapolated from experimental signal to noise data. The linearity study involves ten compounds analyzed at five different concentrations. The response factors (RF) are calculated and discussed. The study concerning the band broadening contributions of the interface involves four independent variables (helium flow, desolvation chamber temperature, source temperature, and 96 methanol) and their effects on peak width. A Box–Behnken experimental design is used and described. Response surfaces are generated from the best fit equation describing the data. / Master of Science

Crosslinked poly-4-vinylpyridine (XPVP) has not previously been used as a size exclusion chromatographic packing material. This material appears attractive for the analysis of nitrogen containing polymers because of its basic nitrogen functionality, and desirable physical properties. Its use as such is investigated with probe compounds in several different mobile phases. Various methods of separation of the XPVP material by particle size are employed. In addition, four column packing techniques were examined. / Master of Science

The analysis of nitrate-ester propellants and explosives has been performed extensively by gas chromatography for the past decade. As capillary GC technology has advanced, new opportunities for the improvement of existing methods have developed. This investigation probes several of these possibilities. The effect on quantitation of: the solvent, the analysis time, and the use of splitless injection were investigated. Precision was shown to be improved by: 1. using a non-volatile solvent (toluene) rather than CH₂Cl₂, 2. using the most time-efficient method that will allow adequate resolution of the components, 3. using splitless injection (0.80 min. splitless time). After these potential improvements of method were investigated, the mechanism employed in splitless injection was investigated. This mechanism is known as the SOLVENT EFFECT. The investigation showed that: 1. non-volatile components required less splitless time to achieve 100% sample transfer to the column; 2. using splitless injection improved precision over split injection; 3. injector liner design had no effect on precision; 4. column overload did not hurt precision, as long as all peaks remain baseline-resolved; 5. the initial column temperature must be below the boiling point of the solvent (how far below did not appear to be very significant); 6. quantitation is improved by using a solvent that is as non-volatile as possible; 7. varying the split ratio after the split vent has reopened (within the range of 20:1 to 500:1) has no effect on resolving peaks that occur extremely close to the solvent peak. / Master of Science

The main objective of this research was to identify the compounds responsible for persistent odors in biosolids during long-term storage using olfactometry measurements and to determine their generation pattern with regard to time of appearance and decline using gas chromatography-mass spectrometry (GC-MS). Another objective of this study was to investigate the effect of various digestion and dewatering techniques on odors and determine if there is a correlation between the peak concentration and time of appearance of short-tem organic sulfur odors and persistent odors. Headspace analysis was used to quantify short-term odor-causing organic sulfur compounds and persistent odors from compounds such as indole, skatole, butyric acid and p-cresol for an incubation period up to 150 days. A unique odor generation pattern was observed for each of the compounds analyzed for all the dewatered cakes tested in this study. Dewatered cake samples were also analyzed to determine their detection threshold by a trained odor panel and the results were consistent with the general pattern of odor generation observed in this study. Positive correlations were observed between the peak concentration of organic sulfur and persistent odor compounds whereas little or no relationship was observed between their times of appearance. The type of sludge used in digestion (primary sludge, WAS and mix) was found to affect the production of odor-causing compounds significantly. Primary sludge produces the highest odors followed by mix. WAS was found to produce biosolids with a low odor concentration. Positive correlation was observed between odor concentration and digestion SRT. Significant reduction in odor concentration was observed when the SRT was increased from 12-days to 25-days. At 45-day SRT, further reduction in odors was not very significant. Moreover, the results from this study indicate that methanogens play an important role in the degradation of both organic sulfur and persistent odors. Although the highest odors during biosolids incubation came from sulfur compounds, the persistent odors must be managed as part of a comprehensive sludge management approach. / Master of Science

A gas chromatographic study was made to quantitatively analyze the effluents produced during the thermal cyclization of several polyimidazopyrrolone (pyrrone) model compounds. The study yielded information on analogous polymeric reactions. The model compounds were programed at 5° C/min from 25° to 400° C and volatile species were purged into a gas chromatograph at 25° intervals. An analysis of the effluents revealed that the cyclization reactions are concerted and generally occur below 250°C. The percent of conversion of the model compounds is readily determined by quantitating those reaction products amenable to gas chromatographic analysis. Only the amide-acid-amine and meta-benzimidazole-acid model compounds exhibited complete conversion to the pyrrone structure. Evidence that decarbo:xylation has occurred in the other compounds is presented. / Master of Science

An LSI-11 micro-processor and a Spectra-Physics model 3500B gradient elution liquid chromatography were interfaced for the purpose of automating the chromatograph, incorporating it into the laboratory data network system and collecting data for Michael Starlings' project. The automation involved the construction of hardware for the control of the chromatograph and for data acquisition and display and the writing of software to operate the interface. The LSI-11 collects data by clock interrupts while displaying the current data buffer on the oscilloscope. It stores all data files on a floppy disk storage device, accessed through the main host computer. An analysis of the data is performed by a peak processing routine, calculating peak area and retention time. The network is the DEC Rr-11/REMOTE system. It operates on a PDP-11-03 with a floppy disk system for mass storage. The laboratory system has three satellites operating under it. They can utilize all of the facilities of the main computer while maintaining a minimal operational configuration. The project also had the purpose of being assimilated into Michael Starlings' data correlation system. The LSI-11 will collect data and send it to the NOVA computer system where it will be stored. The system was tested with several mixtures and the results were found to be accurate and easily obtainable, / Master of Science

The purpose of this investigation was to propose a method to determine the composition distribution, on one hand, and the molecular weight distribution, on the other hand, for block copolymers. The technique selected to determine this kind of information was Gel Permeation Chromatography, because, since its introduction in 1964, it has become the most powerful tool for the rapid characterization of homopolymers. The proposed method is introduced by considering a dual-approach: composition distribution (calibration of detectors with composition) and molecular weight distribution (calibration of columns with composition). The absence of heterointeractions in block copolymers led to a behavior which depends solely on the elution behavior of the corresponding homopolymers. Finally, it is concluded that all this meaningful information about block copolymers can be perfectly obtained when adequate raw Gel Permeation Chromatography data handling, taking into account composition, is done. / M.S.

Carbon tetrachloride (CCl₄ ) was closely evaluated as a carrier solvent in high-performance liquid chromatography (HPLC). The separation and retention trends of ninety-two selected compounds from eleven chemical classes (furans, thiophenes, aromatic hydrocarbons, ethers, esters, ketones, aldehydes, aromatic amines, azaarenes, alcohols and phenols) on three analytical silica-bonded phase (amino (NH₂), cyano (CN) and polar amino-cyano (PAC)) columns were investigated with CCl₄ and refractive index (RI) detection. The sample capacity and column efficiency of each of the NH₂ and PAC columns were measured and compared. Besides, a method of determining unmeasurable capacity factors (k' values) was found and illustrated. / M.S.

Microbore columns were investigated for their application to High Performance Liquid Chromatography. Microbore columns consist of stainless steel tubing, 1/16¹¹ OD x 1mm ID, packed with silica gel or other suitable material. These columns were evaluated in terms of extra-column variance effects, mass sensitivity, and solvent consumption. Three methods of extracting the extra-column variance effects were evaluated. When used with an instrument whose contribution to total peak variance is small compared to the column, microbore columns provide the best performance for analyses where sample is limited or where reduction of solvent usage is desirable. A method from the literature for extracting extra column variance effects was found to be easy and reliable. It is proposed as a useful way of allowing column performance to be compared from instrument to instrument and for determining whether a particular instrument is suitable for use with microbore columns. / M.S.

Separation of complex gaseous mixtures using gas chromatography (GC) is an important step in analytical systems for environmental monitoring, medical diagnosis, and forensic science. Due to its high resolving power, analysis speed, and small sample size, GC, has become the premier technique for separation and analysis of volatile and semi-volatile organic compounds. Miniaturization of analytical systems has become a major trend which is mainly driven by advancements in microfabrication techniques and a need for portable lab-on-a-chip systems for onsite monitoring. Microfabricated columns have been explored for applications in analytical processes like GC in several research studies. These microGC columns typically have open rectangular or open circular cross sections which is a result of the etching process utilized in the fabrication. This work reports the fabrication and performance of a new generation of silicon-on-glass micro-electro-mechanical systems (MEMS) based GC columns with microposts namely "semi-packed." These columns can be fabricated on a 2 cm2-die for a 1 m-long channel or a 1 cm2-die for a 25 cm-long channel. The semi-packed columns have a higher sample capacity as the overall surface area is larger than that of open rectangular columns of the same dimensions. The separation efficiency of these columns is also superior to that of open columns due to the presence of the microposts. As compared to conventional packed columns, the semi-packed columns show lower pressure drops and a more uniform flow profile, both of which contribute to, performance in terms of separation efficiency. / Master of Science