Mixed matrix membranes offer an attractive route to the development of high performance and efficiency membranes required for demanding gas separations. Such membranes combine the advantageous processing characteristics of polymers with the excellent separation productivity and efficiency of molecular sieving materials. This research explores the development of mixed matrix membranes, namely in the form of asymmetric hollow fiber membranes using zeolites as the molecular sieving phase and commercially available high performance polymers as the continuous matrix. Lack of adhesion between the typically hydrophobic polymer and the hydrophilic native zeolite surface is a major hurdle impeding the development of mixed matrix membranes. Silane coupling agents have been used successfully to graft polymer chains to the surface of the zeolite to increase compatibility with the bulk polymer in dense films. However, transitioning from a dense film to an asymmetric structure typically involves significant processing changes, the most important among them being the use of phase separation to form the asymmetric porous structure. During the phase separation, it is believed that hydrophilic sieves can act as nucleating agents for the hydrophilic polymer lean phase. Such nucleation tendencies are believed to lead to the formation of gaps between the polymer and sieve resulting in poor mixed matrix performance. This research focuses on defining procedures and parameters to form successful mixed matrix hollow fiber membranes. The first part of this dissertation describes dope mixing procedures and unsuccessful results obtained using a silane coupling agent to enhance polymer-zeolite adhesion. The next section follows the development of a highly successful surface modification technique, discovered by the author, employing the use of a Grignard reagent. As a test case, two zeolites of different silicon-to-aluminum ratios are successfully modified and used to develop mixed matrix membranes with greatly increased gas separation efficiencies. The broad applicability of the surface treatment is also demonstrated by the successful incorporation of the modified zeolites in a second polymer matrix. The final section of the work describes the novel occurrence of large defects (macrovoids) caused by the presence of large zeolite particles proposing a particle size effect in the formation of such defects.

Fluorescent labeling can improve the detection sensitivity in capillary electrophoretic (CE) separations down to attomolar concentrations. However, most fluorescent labels are not compatible with CE because their fluorescence properties and charge states are pH-dependent, they are often hydrophobic and they have a tendency to significantly change the properties of the analytes after labeling. A group of fluorescent labeling reagents have been prepared whose fluorophores have properties that are optimized for CE separations. These fluorophores have fluorescence properties and charge states that are independent of pH in the 2 < pH < 11 range. Their excitation maxima are also compatible with the 488 nm line of the Argon ion laser. A mono-cationic acridine-based fluorescent label was prepared and was found to not shift the pI of a labeled model protein in capillary isoelectric focusing separation (cIEF). Lower loading, due to increased sensitivity, led to better resolution of closely spaced isoform peaks having a pI = 0.05. A tri-anionic pyrene-based fluorescent labeling reagent was also synthesized and was used in the sodium dodecyl sulfate capillary gel electrophoresis (SDS-CGE) separation of proteins. The fluorophore led to an LOQ in the nM range, and did not alter the migration behavior of proteins in the sieving matrix. A third fluorescent labeling reagent was developed as a solid phase reagent (SPR) where the fluorophore was immobilized on a solid surface through a cleavable anchor. The fluorophore is di-anionic and is based on pyrene. The SPR was designed to allow the simultaneous capture and labeling of an analyte and the efficient release of the label-analyte conjugate under mild acidic conditions. The use of the SPR allowed the labeling of a diamine whose concentration was in the low nanomolar range. The SPR opens up the possibility for mono-labeling and proportional multiple labeling of proteins.

Determination of thallium is important due to its toxic effects on the environment and human health. Extremely low abundance of thallium in earth crust requires very sensitive and accurate methods for determination of this element. Although volatile compound generation is a sensitive, fast and economical method, thallium determination by this method has not been sufficiently investigated in literature, because of the fact that the formation of volatile forms of this element is a difficult task. A continuous flow volatile compound generation system was developed and parameters that affect the analytical signal were optimized. Sample solutions were acidified with 0.5 mol/L HNO3 and prepared in 0.0005% (v/v) rhodamine B and 1.0 mg/L Pd while 0.5% (m/v) NaBH4 stabilized in 0.5% (m/v) NaOH was used as reductant. Fast decomposition and unstability of thallium volatile species affected system performance negatively. Flow injection volatile compound generation studies were carried out with a special system. After optimizations, LOD and LOQ values were calculated as 12 ng/mL and 40 ng/mL according to peak height values in HNO3 medium. Similarly, in HCl medium LOD and LOQ values were calculated as 14 ng/mL and 45 ng/mL. Addition of Te and Pd to the sample solution containing co-enhancement reagent rhodamine B improved volatile compound generation efficiency in peak height by 3.6 and 9.3, respectively. Type of the acid used was affected peak heights and peak shapes of Tl+ and Tl3+ volatile species and HNO3 medium gave better results. By changing the location of introduction for Ar gas, the sources of memory effects and reasons of peak broadening were investigated. Most of the memory effects were coming from the gas-liquid separator (GLS) or before the GLS, as well as T-tube atomizer. Nature and behavior of Tl volatile species were also investigated and it was found that Tl and also Pd were generated in the form of nanoparticles. Transmission electron microscopic (TEM) measurements prove the presence of Tl nanoparticles in the analyte species transported to the atomizer by the effect of carrier Ar gas.

Abstract 2-Methoxy- and 2-trimethylsilyloxyfuran undergo facile ring opening reaction upon treatment with metal carbeniod. Treatment of 2-methoxy-furan with ethyl diazoacetate and aryl-£\-diazocarbonyl compounds under metal catalysis afford (Z,E)-2,4-hexadienedioate and aryl-6-oxo-2,4-hexadienoates respectively. When 2- trimethylsilyloxyfuran was used, desilylation occurred to give directly the monoprotected (Z,E)-muconic acid and 6-aryl-6-oxo-2,4-hexadienoic acids. We have synthesized aromatic dienyl diketone using the method of Wenkert from aromatic diazo ketone and 2-methylfuran. This method was found to give a mixture of (Z,E)/(E,E)-dienyl diketones. The anticancer, antibacterial and vasorelaxing activities are evaluated. All the aromatic dienyl diketones synthesized exhibit strong in vitro inhibition of tumor cell and micro0organisms growth respectively, and three of these compounds exhibit strong vasorelaxing effect. Reaction of 1,6-dioxo-2,4-diene with P2S5 and Lawesson¡¦s reagent affords the 2,5-disubstituted thiophene. This reaction can take place regioselectively in the presence of BF3-etherate catalysis, useful for the synthesis of arylthiophene. We have demonstrated a new methodology for the facile synthesis of arylthiophene.

Pirmą kartą Lietuvoje nustatytas bendras fenolkarboksirūgščių kiekis Achillea millefolium L. vaistinėje augalinėje žaliavoje. Taip pat pirmą kartą nustatytas populiacinis bei morfologinis kiekybinės rūgščių sudėties kintamumas Lietuvos natūraliose augavietėse augančių kraujažolių augaluose. Nustatytas bendras fenolkarboksirūgščių kiekis žolės 70 proc. etanoliniuose ekstraktuose vidutiniškai siekė 58,690±4,279 mg/g. Taip pat nustatyta, kad A. millefolium augalinėms žaliavoms būdingas ženklus fenolkarboksirūgščių sudėties rodiklių kintamumas, tiesiogiai priklausantis nuo augalo morfologinės dalies. Bendras fenolkarboksirūgščių kiekis žiedų žaliavose vidutiniškai siekė 58,029±3,492 mg/g. Lapų žaliavose vidutiniškai sukaupiama 102,150±7,50 mg/g, tai yra beveik du kartus daugiau nei žiedų ir žolės žaliavose, stiebuose - 22,722±2,928 mg/g. Nustatytas ženklus fenolkarboksirūgščių kiekinės sudėties įvairavimas tarp tirtų kraujažolių cenopopuliacijų. Vaistinės žaliavos bandinių grupėje bendras rūgščių kiekis skirtingose cenopopuliacijose kito nuo 33,490 iki 86,474 mg/g, žieduose - nuo 40,240 iki 73,022 mg/g, lapuose - nuo 74,110 iki 150,176 mg/g, stiebuose - nuo 15,605 iki 43,381 mg/g. Atlikus statistinę analizę norint palyginti tirtų bandinių grupių vidurkius, tirtose žaliavose nustatyta statistiškai reikšmingų skirtumų. Eksperimentinių duomenų sklaidai apibūdinti apskaičiuoti bandinių grupių variacijos koeficientai (žolės – 26,29 proc., žiedų – 19,03 proc., lapų – 23,25 proc... [toliau žr. visą tekstą] / For the first time ever in Lithuania, the general amount of phenolcarboxylic acids was measured in the raw plant material of Achillea millefolium L. medicinal plants. The population and morphological variance of the quantitative content of the acids in yarrow plants growing in the natural habitats of Lithuania was also determined for the first time. The overall amount of phenolcarboxylic acids was determined to be 58,690±4.279 mg/g in 70 percent ethanol extracts of the herb. It was also determined that significant variability exists in indicators of the phenolcarboxylic acid content of A. millefolium plants. This is directly dependent on the morphological part of the plant. The total average of the phenolcarboxylic acids content in flowers was 58,029±3,492 mg/g. The total average in leaves was 102,150±7,50 mg/g, almost two times higher the content found in the flowers and herbs. The average acids content accumulated in stems was 22,722 ± 2,928 mg/g. Determinated sign variability of the content of phenolcarboxylic acids in the investigated cenopopulations of yarrow. The total acids content of different cenopopulations in the raw plant materials of yarrow ranged from 33,490 to 86,474 mg/g, in flowers - from 40,240 to 73,022 mg /g, in leaves - from 74,110 to 150,176 mg/g, in stems - from 15,605 to 43,381 mg/g. Statistical comparison of sample group averages found statistically significant differences between sample group averages. The dispersion of the experimental data was... [to full text]

The efficacy of injection-driven remediation techniques for non-aqueous phase liquid (NAPL) source zones is limited by the principle that fluid flow is focused along paths of least hydraulic resistance. The pressure pulse technology stands among a number of innovative methods that have been developed with the aim of overcoming or mitigating this limitation. The objective of this research was to observe and document differences in saturated groundwater flow and solute transport between an injection using a conventional or continuous pressure delivery approach and an injection using a pressure pulsing instrument. The underlying motivation was to identify engineering opportunities presented by pressure pulsing with the potential to improve remediation efficiency at contaminated sites. A series of tracer injections were conducted in the unconfined aquifer at the University of Waterloo Groundwater Research Facility at Canadian Forces Base (CFB) Borden near Alliston, ON (homogeneous fine sand), and in the shallow aquifer at a groundwater research site located on the North Campus at the University of Waterloo (moderately heterogeneous with discrete layers varying from fine sand to silt). A single injection well was used at each site for both the conventional and pressure pulsing injections. Different tracers were used for consecutive injections. Bromide, Lithium, Chloride, and fluorescent dyes (Rhodamine WT and Sulforhodamine B) were used. Formation pressurization data was captured by pressure transducers. The spatial distribution of the injected tracers was monitored at a series of multilevel wells. A groundwater flow and solute transport modeling exercise (MODFLOW and MT3DMS numerical engines) simulating the rapid boundary pressure modulation that occurs in association with pressure pulsing was conducted to complement the field injections. A two-dimensional domain was used to conduct a parametric investigation of pressure modulation and its effect on flow and transport. A three-dimensional domain served to scale-up the two-dimensional results and for benchmarking against field observations. Pressure pulsing simulation results reveal that repeated sudden onset of injection cessation produces brief periods of gradient reversal near the injection well and the development of a mixing zone around the injection well. The spatial extents of this mixing zone are highly dependent upon the hydraulic diffusivity of the medium. Greater heterogeneity in combination with presence of high hydraulic diffusivity pathways maximized the extent of the mixing zone and the magnitude of transverse and reversal hydraulic gradients. Lower pulsing frequency and higher pulsing amplitude favoured a more significant mixing zone, though these effects were secondary to geologic properties. Use of the pressure pulsing tool did not manifest into distinct changes in tracer breakthrough at either field research site. Comparison between tracer tests was complicated by sorption of fluorescent dyes and ongoing well development. Solute transport simulation results demonstrated augmentation of dispersion arising from the mixing zone phenomenon, but no distinct changes in advection.

Reagent injections designed to provide in stiu mass destruction of soil and groundwater contaminants are commonly prone to failure due to inadequate distribution of the injected reagent. Reagent injections, in particular in situ chemical oxidation (ISCO) injections, require contact between the treatment reagent and targeted contaminant to allow for mass destruction in source zones and plumes. Subsurface heterogeneities that exist at all spatial scales prevent remediation specialists from accurate prediction of reagent distribution in the subsurface, even when significant site characterization and hydraulic testing has previously taken place. A prototype probe system was developed to provide real-time monitoring of the distribution of injected reagents. This thesis focused on laboratory testing of the system to verify that the design was capable of indicating the presence of an injected reagent in the field. Temperature and two-wire dipole resistance sensors were developed with low-cost materials to provide feedback on the electrical conductivity (EC) signatures produced by typical reagents mixed as salt solutions. Sensors were attached to sections of PVC conduit and wired to a data acquisition system to control measurements and store data. The temperature sensor was found to accurately respond to temperature changes in comparison to a commercial datalogger. Measured temperature differences between the constructed sensor and commercial datalogger were relatively constant, indicating that the constructed sensor could be calibrated to measurements from a commercial logger. Static cell experiments were conducted in beakers with varying concentration sodium chloride (NaCl), potassium permanganate (KMnO4) and sodium persulfate (Na2S2O8) solutions to determine dipole resistance sensor response to variations in EC. Different fixed resistors were wired with the dipole sensor circuit to determine the impact on sensor readings. Results indicated a nonlinear correlation between two-wire dipole resistance sensor response and increasing EC. Each constructed dipole sensor behaved uniquely. Raw sensor response was calibrated to EC by accounting for the influence of the fixed resistor. Data was fit to a second-order polynomial with form y = aEC2 + bEC + c, with r2 ranging from 0.92-1.00 for experiments with 4-6 measurement points. Calibrations were accurate within the range of EC for each static cell experiment; trends extrapolated beyond the measurement range were subject to significant error. The choice of fixed resistor did not appear to alter the accuracy of probe calibrations. Flow cell experiments were designed to analyze dipole resistance sensor response to continuous changes in EC. EC breakthrough curves (BTCs) were produced by injecting NaCl tracer solutions into the flow cell. Initial flow cell experiments conducted in an open water system showed agreement between dipole sensor measurement and handheld EC measurements on the rising limb of BTCs and divergence between the two datasets on the falling limb of BTCs. To resolve these issues, a more sophisticated tank with a porous medium was built and tested to compare sensor response from s prototype probe and a commercial EC datalogger. EC BTCs were measured under two scenarios: (1) conditions with deionized water (DI) circulating through the tank as the background solution, and (2) conditions with a simulated groundwater solution with elevated EC circulating through the tank as the background solution. BTCs produced agreement between EC recorded by the commercial logger and dipole resistance measurements for both the rising and falling limbs of BTCs. Results indicated the dipole resistance sensor was not capable of resolving fine changes in EC that occurred during breakthrough. A calibration of all in situ measurements from the experiments with porous medium confirmed the simulated groundwater experiments were subject to significantly less variability than the deionized water experiments. The calibration applied to the simulated groundwater measurements produced BTCs that matched very closely with those recorded by the commercial logger. Two field trials were also conducted during ISCO injections at contaminated sites where probes were installed in existing monitoring wells. The field trials did not successfully correlate dipole resistance sensor measurements with oxidant concentration. Observations from the second trial indicated the dipole sensor measurements correlated with EC of water samples. This work has provided a theoretical representation of two-wire dipole resistance sensor response to EC and has verified expected results through laboratory experiments. It has analyzed the influence of temperature and choice of fixed resistors on two-wire dipole resistance sensor readings, has extensively tested sensor response to EC during static cell and BTC experiments, and has displayed the prototype probe is capable of indicating the presence of injected reagents that have an EC signature. Further research avenues include pilot-scale testing in the field and developing a design for use with a direct-push rig.

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 5 uppsatser.

Alguns cientistas ambientais prevêem que a poluição dos solos será um dos maiores legados com grandes impactos para as gerações futuras, pois atualmente ainda existe desconhecimento das fontes poluidoras e da sua extensão. O Brasil, devido a sua extensão territorial, suas bacias hidrográficas, número de postos de abastecimentos e controles ambientais ainda ineficazes, está muito exposto a esse tipo de poluição. Atualmente, há no Brasil mais de 34.300 postos de combustíveis, com volume de 65.000.000 m3 de gasolina e diesel consumidos anualmente, conforme dados da Agência Nacional do Petróleo Gás Natural e Biocombustíveis , ANP, em 2008. Sendo assim, a exposição e contaminação dos solos e dos lençóis freáticos com constituintes aromáticos do diesel e gasolina torna-se um sério problema ambiental. Dentro deste grupo, encontram-se o benzeno, tolueno, xileno, conhecido como BTEX e os hidrocarbonetos policíclicos aromáticos, conhecido como PAH. Este trabalho tem como objetivo estudar a remediação in-situ de um posto de combustíveis na região do ABC Paulista, no Estado de São Paulo. Aplicando-se a técnica de Processo Oxidativo Avançado via reagente de Fenton (H2O2 + Fe2+ &#8594; Fe3+ + OH- + OH . ), o radical hidroxila gerado mineraliza compostos aromáticos, decompondo-os definitivamente. Amostras de água do posto em estudo apresentavam elevados teores de BTEX e PAH, 2,58 mg.L-1 e 0,298 mg.L-1 respectivamente, estando em níveis não tolerados pelo órgão ambiental paulista CETESB sendo necessária a intervenção para tratamento da área. Com os níveis de poluentes e o perfil hidrogeológico identificados, a remediação foi iniciada com injeções no solo de peróxido de hidrogênio a 8%v.v, FeSO4 a 0,40 mg.L-1 e solução à base de NPK (nitrogênio, fósforo e nitrogênio) a 100 mg.L-1 como nutrientes para os microorganismos do solo. Estes valores são provenientes de experimentos anteriores e tratamentos já realizados. Foram conduzidas campanhas de injeção trimestrais com 100 litros desta solução completa como reagente , e medições trimestrais de BTEX, PAH e outros parâmetros de controle, que foram indicando o sucesso do tratamento. Após 18 meses o local foi considerado tratado pelo órgão ambiental, onde monitoramentos semestrais estão em continuidade para garantir o resultado do tratamento e das ações corretivas. Assim, o estudo real da remediação de solos contaminados com os poluentes orgânicos via processo de Fenton, com concentração de H2O2 a 8%v/v, e FeSO4 a 0,40 mg.L-1 demonstrou-se uma técnica de sucesso. O entendimento dos resultados da remediação, mesmo sujeitos aos fenômenos naturais, como intempéries e chuvas, é uma experiência grande, pois por mais reais que simulações em laboratório possam ser, é muito difícil incluir nestes sistemas, as variações que um tratamento real está exposto / Some environmental scientists foresee that soil pollution would be one of the biggest legates to the next human generation, because nowadays there is not enough knowledge about all impacts and origins of such source of pollution. From inadequate batteries disposal to leakage of gasoline underground storage tanks, the range of sources of soil and groundwater pollution is immense. The Brazilian territory and its groundwater are greatly exposed to such contamination, also due to lack of environmental controls and government actions. Luckily, there are available some soil remediation technologies and good literature and previous researches. Nowadays, there are in Brazil around 34,300 gas stations all over the country, and a volume of 65,000,000 m3 of gasoline and diesel consumed annually, according to the National Petroleum Agency (ANP) in 2008. The probability to occur a soil and groundwater contamination is high and accurate processes are needed to quickly stop the underground contamined plume with BTEX (benzene, toluene, ethyl benzene and xylenes), found in gasoline and combustion byproducts and the wellness to people and other organisms. This work has the intention to elucidate an in-situ soil and groundwater remediation process. The site treated was a gas station located in São Paulo state, responsible for almost 60% of gas stations in Brazil. Application of the Advanced Oxidation Process, using Fenton reaction (H2O2 + Fe2+ &#8594; Fe3+ + OH- + OH . ), which is a process that deliver into soil-water contamined systems, the hydroxyl radical in order to break undesired aromatic compounds. Water samples from the gas station in study, presented prohibited levels of BTEX and PAH according to the CETESB São Paulo Environmental Company which reason started the soil remediation and the area intervention. After understood of hydro-geological characteristics and the level of pollutants, the Fenton process started with well injections containing hydrogen peroxide ( 8% v/v), iron (II) salts (0,4 mg/L) and NPK based nutrients. At quarterly injections with 100 liters each, the further monitoring of BTEX, PAH and other control parameters, indicated the success of the treatment. After 18 months, the site was considered as remediated. Periodically sampling at each 6 months guarantee that the corrective actions kept successful. Based on that, the in-loco study about remediation of contaminated soils, with organic pollutants presents a great experience, and the Fenton reaction demonstrated a technique of outstanding success. The understand of real and in-situ results, even subjected to rain and other natural phenomena, gives expertise to treat real sites and help the society to stop such contamination. Moreover than laboratory simulation, the real remediation gives a complete snapshot about the Fentons reaction at the soil

A common practice amongst street drug manufacturers and dealers is to combine the illicit drug of abuse they intend to distribute with additional substances. Substances added in an attempt to mimic or enhance the desired effect of the drug of abuse are known as adulterants as opposed to diluents, which are added simply to increase the weight of the product. By definition, an adulterant has a physiological effect on the body and as physiologically active compounds these adulterants may have side effects apart from the drug it is added to. They can be minimal, treatable, or otherwise manageable while others can be worse than those incurred from the drug of abuse itself. Due to varying trends in street drug purity, an effort must be made to understand the effects adulterants and diluents, as well as mixtures thereof, may have on forensic drug analysis. Colorimetric spot test analysis is typically performed using a representative sample of the raw, suspected drug material. These tests are often employed in the lab prior to any attempt to isolate a specific compound or at the scene before an arrest is made. This being the case, the reagents will be exposed to and have the potential to react with anything present in the sample with the drug of abuse. While much work has been done regarding the specificity and cross reactivity of colorimetric spot tests, limited information is available about how mixtures of adulterants may affect the results. This research consists of two parts which approach the common theme of adulterants differently. The first part is a literature based investigation into the pathological side effects of several common drug adulterants. The specific compounds discussed are: levamisole, phenacetin, atropine, and several topical anesthetics (benzocaine, lidocaine, prilocaine, and procaine). A review of articles from the scientific literature was conducted in order to convey what is known in the medical field regarding the effects these compounds can have on the body. The second part of this research was a laboratory based investigation which analyzed the effects of twenty-three common adulterants on two colorimetric spot tests: the Marquis reagent for the presumptive identification of heroin, morphine, amphetamine, methamphetamine, and 3,4-methylenedioxy-N-methamphetamine (MDMA) and the modified Scott test for the presumptive identification of cocaine. This was performed in order to observe the reactivity of these compounds so that a better understanding of the effect their presence can have on the analysis of seized drug samples using these tests could be obtained. The literature review portion of this research revealed that the adulterants levamisole, atropine, phenacetin, and the topical anesthetic adulterants lidocaine, prilocaine, benzocaine, and procaine, can be toxic and have severe, deleterious effects on the body in both chronic and acute exposures. Levamisole stimulates the immune system resulting in the production of self-reactive antibodies that attack neutrophils. This causes an autoimmune disorder that weakens the immune system and causes leukocyte agglutination leading to necrotizing vasculitis. Atropine functions to decrease the parasympathetic tone and increase the sympathetic tone in the body. An overdose can cause anticholinergic toxicity, a syndrome very similar to sympathomimetic toxidrome caused by cocaine overdose. Both are characterized by hypertension, hyperthermia, tachycardia, ataxia, disorientation, and mydriasis. However, they can be distinguished as anticholinergic toxicity causes dry and flush skin and mydriasis which is unreactive to light while sympathomimetic toxidrome causes profuse sweating and mydriasis which is reactive to light. Phenacetin is metabolized to O-ethyl-N-acetyl-p-benzoquinone imine (O-Et-NAPQI), a highly reactive and unstable electrophile. It is capable of covalently binding with proteins and other cellular components, including deoxyribonucleic acid (DNA). This leads to mutagenesis and subsequent tumor generation as well as apoptosis and necrosis of various tissues in the bladder and kidneys. The topical anesthetics have each been associated with the development of methemoglobinemia. This is a condition caused by an increase in the concentration of methemoglobin in the blood. Methemoglobin binds more strongly to oxygen so that it cannot be released to the tissues resulting in oxygen starvation. This was found to be caused by the metabolism of prilocaine and lidocaine to the oxidative compounds O-toluidine and 2,6-xylidine respectively. The cause has not been previously reported for benzocaine or procaine. The laboratory portion of this research revealed the impact several adulterants and their mixtures can have on colorimetric spot tests. Testing with approximately 1 mg of sample material revealed that eight out of the twenty-three adulterants reacted with the Marquis reagent to cause a color change within 15 minutes. Of the ten 3-component mixtures tested, eight resulted in a color change. Of the six five-component mixtures, four resulted in a color change; of the six eight-component mixtures, three resulted in a color change; and of the six ten-component mixtures, five resulted in a color change. Of the color changes observed, none were consistent with the "expected" color change for a presumptively positive result of the Marquis test. Testing with the adulterant diphenhydramine revealed that this compound had a unique and intense reaction with the Marquis reagent. This compound initially reacted by turning the liquid a vibrant yellow-green upon contact with the sample. Prior to 2 minutes, solid red-brown aggregates formed in the liquid and proceeded to increase in size while the reagent solution darkened to a red-black color over the 15 minutes of observation. Mixtures containing diphenhydramine each reacted differently. Solid material did not form in the mixture tests and the color changes observed ranged from light orange to a dark red-orange. In addition, one 3-component mixture containing adulterants which did not cause a color change when tested individually (diltiazem, acetaminophen, and quinine) was observed to cause a light brown color to develop, which darkened over the 15 minutes of observation. The results for the modified Scott test showed that the complexity of this test has made it highly specific for cocaine. None of the individual components or mixtures tested reacted in a manner consistent with a presumptively positive identification for cocaine hydrochloride (HCl) or cocaine base for all three steps. Of the twenty-three adulterants tested, eight of the twenty-three gave a similar result to cocaine base in step 1, however, of these eight, only one (quinine) gave a similar result to cocaine base in step 2, and this adulterant did not react consistently to cocaine base in step 3. The research using the adulterant mixtures revealed that the compounds present in these samples tended to react individually with the modified Scott test reagents. In other words, the results for each mixture appeared as a combination of the individual results for each component. While the results observed for the adulterants and mixtures tested were not consistent with the expected presumptively positive results for the drugs these tests are used to detect, it was concluded that the presence of adulterants in a sample has the potential to affect the results of a colorimetric spot test in a variety of ways. Given that these tests are typically employed on samples of raw suspected drug material, it is important that analysts understand the impact adulterants can have on the interpretation of presumptive drug tests.