A cannabinoid refers to any natural or synthetic compound that interacts with the CB1 and CB2 receptors. There are currently three different groups of cannabinoids: endogenous cannabinoids, phytocannabinoids and synthetic cannabinoids. The most common phytocannabinoid is delta-9-tetrahydrocannabinol (THC), which is the active component in the Cannabis sativa or marihuana plant1–3. Two examples of synthetic cannabinoids that are present in case reports from 2012 to 2018 are AB-FUBINACA and AB-PINACA4–7. THC and synthetic cannabinoids are commonly encountered drugs in forensic toxicology cases, therefore, being able to extract these compounds and their metabolites is imperative for toxicological interpretation. There are a variety of commercially available sample preparation techniques for these analytes. Companies such as UCT, Biotage, Millipore-Sigma, Tecan, and Thermo Fisher Scientific manufacture these products. The focus of this research was to evaluate these techniques for their cleanliness, efficiency and cost effectiveness. Sample preparation techniques are designed to remove the different components of the matrix and other prescription or illicit substances present in the sample that could interfere with the assay, increase the analyte recovery, extraction efficiency, decrease variability, and clean-up the sample to allow for less instrument downtime and longer column life8. This study focused on comparing a liquid-liquid extraction (LLE), solid phase extraction (SPE), and supported liquid extraction (SLE). The primary purpose of this study was to develop and validate the three above mentioned sample preparation techniques for the analysis of THC, 11-hydroxy-THC, 11-nor-9-carboxy-THC (THCCOOH), AB-FUBINACA, AB-FUBINACA metabolite 3, and AB-PINACA in blood and urine. Parameters assessed followed Academy Standards Board (ASB) Standard 036, Standard Practices for Method Validation in Forensic Toxicology, including recovery, suppression, and matrix effects. For urine and blood analysis, the calibration range was determined to be 1 ng/mL to 50 ng/mL for all three techniques. Urine recovery was highest for the LLE method, with all compounds having a recovery greater than 50%. The SLE method had the lowest LOQ results for urine, with 0.5 ng/mL for 11-hydroxy-THC and THCCOOH, 0.75 ng/mL for THC, AB-FUBINCA and AB-FUBINACA metabolite 3, and 1 ng/mL for AB-PINACA. Ion suppression was reduced using the SLE method for urine along with having the shortest sample preparation time of 1 hr for up to 48 samples. For blood analysis, the LLE method had the greatest recovery of all analytes. The LLE method also had reduced suppression and matrix effects compared to the SPE method. Sample preparation was shorter for the SPE method, consuming 2 hrs for an average sample batch, compared to 4 hrs for the LLE method, which included a 2 hr freezing step. In conclusion, for urine analysis, all three sample preparation techniques were acceptable for the analysis of THC, synthetic cannabinoids, and their metabolites, with the SLE method being the preferred method. For blood analysis a LLE and SPE method were developed and are adequate for the analysis of THC, synthetic cannabinoids, and their metabolites, with the LLE method being the preferred method.

In forensic toxicology, analysis of drugs and metabolites in biological fluids is performed to determine cause of death, suspected drug use, drug facilitated sexual assaults, or whether someone was driving under the influence. Analyte identification and concentration determination can be determined in a variety of matrices (e.g., blood, urine, or oral fluid) and can be complex. It is therefore necessary to have optimal sample preparation and instrumental conditions that work for all matrices of interests. Determining the best approach can be challenging due to the amount of time and resources to perform expansive evaluations of sample preparation, stationary/mobile phases, liquid chromatography (LC) conditions and mass spectrometry (MS) operating parameters. In this study three different sample preparation methods were validated for blood and urine. The three sample preparation methods were solid-phase extraction (SPE), supported liquid extraction (SLE), and liquid-liquid extraction (LLE). Six different drug groups were used as the analytes being tested by the methods. These drug groups were amphetamines, local anesthetics, opioids, hallucinogens, antidepressants, and novel psychoactive substances (NPS). A total of twenty-three drugs were used: amphetamine, methamphetamine, (3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), and 3,4-methylenedioxymethamphetamine (MDMA), benzoylecgonine (BZE), cocaine, lidocaine, codeine, methadone, morphine, 6-monoacetylmorphine (6-MAM), fentanyl, oxycodone, lysergic acid diethylamide (LSD), phencyclidine (PCP), amitriptyline, citalopram, fluoxetine, trazodone, ethylone, α-pyrrolidinopentiophenone (α-PVP), and 25I-NBOMe. The methods were validated according to guidelines set forth by the Scientific Working Group for Forensic Toxicology (SWGTOX) Standard Practices for Method Validation in Forensic Toxicology and the American Academy of Forensic Science (AAFS) Standards Board (ASB) draft of Standard Practices for Method Validation in Forensic Toxicology. Parameters of calibration model, bias, precision, limit of detection (LOD), limit of quantitation (LOQ), dilution integrity, ion suppression/enhancement, interference studies, and stability were evaluated. Recovery was also assessed to determine the efficiency of the extraction. Calibration models met the 0.98 R2 minimum requirement. For all sample preparations the compounds evaluated in each were found to be stable for at least 72 hours. Interferences were found to be similar across all three sample preparation methods. Parameters of bias, precision, and dilution integrity were largely comparable between all three methods. Overall for LOD, SLE resulted in lower values for blood and urine ranging for 0.1 to 5 ng/mL. Overall for LOQ, SLE resulted in lower values for blood and LLE resulted in lower values for urine in the range of 0.5-10 ng/mL. SLE resulted in the highest recovery for all twenty-three analytes, due to LLE failing to extract consistently or completely for benzoylecgonine, morphine, and 6-monoacetylmorphine. Overall, SLE resulted in the lowest percent values for ion suppression and enhancement for both blood and urine. Overall, blood resulted in high ion suppression (exceeding -20%) for SPE and LLE. Final determination overall was that SLE was the best sample preparation method for all twenty-three analytes. This was determined based on the evaluation of recovery, ion suppression/enhancement, and LOD, as well as sample preparation time. Sample preparation time for SLE was approximately 1 hour, while SPE took 2.5 hours and LLE 2 hours.

In a forensic investigation involving oil, a comparative analysis named oil spill fingerprinting between a source and an oil spill is normally performed. It is based on detecting a certain selection of biomarkers with gas chromatography (GC) coupled to mass spectrometry (MS) which are later divided into diagnostic ratios (DRs). An international guideline formed by European Committee for Standardization (CEN) denoted CEN/TR 15522-2:2012 describes the process of conducting oil spill fingerprinting. This method is currently being inspected and adjusted for standardization into EN 15522-2:2022. One section of the upcoming standard describes sample clean-up which is important to inhibit possible matrix effect that could either enhance or reduce peak intensity in the chromatogram. There is yet no conclusive SPE (Solid Phase Extraction) protocol in the current draft version of EN 15522-2:2022. The aim with this study was to develop such a protocol. Development included comparative testing of the recommended stationary phases silica and Florisil®. Additionally, the effect of both elution solvent and elution volume were investigated. The protocol must pass validation criteria to be implemented at National Forensic Centre (NFC) and possibly be used in the final version of EN 15522-2:2022. A successful method for Heavy Fuel Oil (HFO), diesel and lubricating oil was achieved with activated Florisil® as stationary phase, eluted with 6 ml dichloromethane (DCM). If the evidence material is suspected to contain FAMEs (Fatty Acid Methyl Esters), then 2 % acetone should be added to the DCM. The final SPE column was packed with 0.5 glass wool, 4 cm Florisil® and 0.5 cm sodium sulfate. Based on successful validation result, the SPE protocol should be considered for the final version of EN 15522-2:2022 as well as for implementation at NFC.

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In spite of the stablility (lack of reactivity) of diamond powder, I have developed a method for tethering alkyl chains and polymers to deuterium/hydrogen-terminated diamond. One method is through ether linkages via thermolysis of di-tert-amyl peroxide (DTAP). This reaction with DTAP has also been applied to grow polymers on the diamond surface. The other method is atom transfer radical polymerization (ATRP), which was applied to grow polystyrene at the surface of diamond. Both polystyrene-modified diamond and sulfonated polystyrene-modified diamond can be prepared by either method, and can be used for solid phase extraction. Diamond stationary phases are stable under basic conditions, which is not the case for silica-based stationary phases. Surface characterization was performed by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFT). While the main focus of my graduate research has been the surface modification of diamond, I also describe other projects on which I have worked. The use of radical-based processes for modifying diamond is related to a different radical-based synthesis of monolayers or polymers I performed by scribing silicon (Siscr). After preparation of homogeneous olefin-terminated monolayers on scribed silicon made from 1,9-decadiene and chemisorption of Grubbs' catalyst, ring-opening metathesis polymerization (ROMP) of norbornene was demonstrated. These surfaces were characterized by XPS and ToF-SIMS. I also investigated the extent of PDMS oligomers transfer onto different surfaces with a wide range of hydrophobicities, using an uninked, unpatterned PDMS stamp. The effect of surface free energy on PDMS transfer in microcontact printing was investigated and the relationship between the amount of PDMS in ToF-SIMS spectra and the surface tensions of initial surfaces was revealed. Therefore, PDMS transfer can be applied as a probe of surface free energies using ToF-SIMS, where PDMS preferentially transfers onto more hydrophilic surface features during stamping, with little transfer onto very hydrophobic surface features. In much of my thesis work, I performed multivariate analysis of my data, especially of my ToF-SIMS data. Such chemometrics methods include principle components analysis (PCA), partial least squares (PLS) cluster analysis, and multivariate curve resolution (MCR). I also applied these tools to analyze electrospray ionization (ESI) mass spectrometry data from a lipidomics study.

No description available.

Polychlorinated biphenyls (PCBs) and their metabolic derivatives are ubiquitous environmental contaminants. These compounds are of concern because of their persistence and bioaccumulation in nature. PCBs and the hydroxylated metabolites have shown endocrine-disrupting activity. A method of detection in surface water samples is important to identify and quantify the environmental contamination. In this research we have attempted to develop a method of detection. Six representative polychloromethoxybiphenyls (PCMBs) were prepared. The corresponding polychlorobiphenylols, hydroxylated PCB metabolites (OH-PCBs), were prepared from the PCMBs. A method coupling solid phase extraction with liquid chromatography, on-line electrospray ionization, and mass spectrometry (SPE-LC/ESI/MS) was developed for detection of the OH-PCBs in distilled and surface water samples.

Orientadores: Susanne Rath, Jarbas José Rodrigues Rohwedder / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-19T11:12:21Z (GMT). No. of bitstreams: 1 Orlando_RicardoMathias_D.pdf: 5151319 bytes, checksum: 53a60cd9c94d86b8a9e269a87ef0c9ac (MD5) Previous issue date: 2011 / Resumo: O preparo de amostra representa uma etapa determinante e crítica no processo de análise e a extração em fase sólida (SPE) é uma técnica amplamente empregada no preparo de matrizes complexas. O objetivo deste trabalho foi o desenvolvimento de dispositivos e procedimentos que permitem aplicar campos elétricos em SPE empregando cartuchos (E-SPE®), visando adicionar os mecanismos da eletroforese ao processo cromatográfico. Para tanto, foram desenvolvidos eletrodos e cartuchos que possibilitam a aplicação de campos elétricos, além de um sistema para monitorar e controlar parâmetros eletrocromatográficos tais como: vazão, corrente elétrica, potencial elétrico e temperatura. Com esses dispositivos foram realizadas extrações com aplicação de campo elétrico empregando compostos modelo aniônicos, catiônicos e anfotéricos. Para permitir uma melhor compreensão dos fenômenos envolvidos foram avaliados diversos parâmetros de extração, entre esses: concentração de íons em solução, pH, modificador orgânico, volume de solução de lavagem e tipo de sorvente. O sistema foi avaliado também na determinação de antimicrobianos em leite. Dependendo da polaridade empregada sobre os eletrodos, a aplicação do campo elétrico foi capaz de modular (acelerar ou retardar) a saída dos compostos modelo do cartucho. Os resultados de extração obtidos demonstraram a eficácia dos dispositivos desenvolvidos, além da grande potencialidade do uso de campos elétricos em SPE para obter maiores recuperações dos analitos de interesse e/ou remoção de interferentes / Abstract: Sample preparation is a crucial and determinant step for the analysis process and solid phase extraction (SPE) is a widely used technique in the preparation of complex matrices. The aim of this work was the development of devices and procedures for applying electric fields to SPE cartridges (SPE-E ®), in order to add the mechanisms of electrophoresis to the chromatographic process. For this purpose, electrodes and cartridges that allow the application of electric fields were developed, besides a system to monitor and control electrochromatographic parameters such as: flow, electric current, electric potential and temperature. By means of these devices, extractions with application of electric fields were performed using anionic, cationic and amphoteric model compounds. In order to allow a better understanding of the phenomena involved several extraction parameters were evaluated, among these: the concentration of ions in solution, pH, organic modifier, volume of washing solution and type of sorbent. The system was also evaluated for the determination of antibiotics in milk. Depending on the polarity of the electrodes used, the application of an electric field was able to modulate (accelerate or retard) the output of the model compounds from the cartridge. The extraction results obtained showed the effectiveness of the devices developed, and the immense potential of the use of electric fields in SPE to obtain better recoveries of the analytes and/or for removing interferents / Doutorado / Quimica Analitica / Doutor em Ciências