Metabolômica é a técnica que analisa quantitativamente metabólitos endógenos e exógenos de baixa massa molecular encontrados em biofluidos e tecidos. Estas pequenas moléculas representativas encontradas em um sistema biológico abrangem carboidratos, ácidos graxos, nucleotídeos, aminoácidos entre outras classes de compostos. Alguns estudos têm mostrado a importância da manutenção da saúde bucal para pacientes com doença renal crônica (DRC). DRC, um problema mundial de saúde pública, pode ser definida em função da presença de danos renais ou de uma taxa de filtração glomerular < 60 mL/min por 1.73m2 por 3 meses, independente da causa. Desta forma, o objetivo deste estudo foi identificar e interpretar a função de metabólitos salivares e de urina de pacientes com DRC e sua possível associação com a doença periodontal (DP). Trinta adolescentes e adultos jovens, 12-18 anos, diagnóstico médico definitivo de DRC, cadastrados no CAPE (Centro de atendimento a pacientes especiais) da Faculdade de Odontologia e no Instituto da Criança da Faculdade de Medicina - Universidade de São Paulo (USP), fizeram parte deste estudo. O grupo controle também foi composto por 30 indivíduos, porém, clinicamente saudáveis. Todos os participantes receberam informações prévias à coleta de urina e saliva. As amostras de saliva e a primeira urina da manhã foram coletadas e armazenadas a -80°C até a realização da análise. A análise periodontal foi realizada por meio do índice de higiene oral simplificado (OHI-S), sangramento à sondagem e profundidade de sondagem. Todas as amostras foram avaliadas no departamento de Engenharia Química da Escola Politécnica da USP por meio de análise de cromatografia gasosa acoplada ao espectrômetro de massa (GC-MS). As análises estatísticas foram realizadas por meio da análise de componentes principais (PCA), testes de Mann-Whitney e Kruskal-Wallis. A quantificação relativa de cada metabólito mostrou maiores concentrações estatisticamente significativas entre pacientes com DRC sem DP e com DRC e com DP, de alanina (p<0.0001), glicina (p<0.0001), tirosina (p=0.021), serina (p<0.0001), prolina (p<0.0002), leucina (p<0.0003), citrulina (p<0.0001) e arginina (p<0.0002). Os valores médios da concentração de p-Cresol também mostraram-se alterados para os mesmos grupos citados acima. Grupos com DRC mostraram concentrações alteradas de ácidos carboxílicos como ácido butírico e de dimetilarginina. Concluímos, portanto, que ambas as patologias estimulam o processo oxidativo sintetizando metabólitos como ácido butírico, L-prolina, dentre outros, os quais podem potencializar a severidade da DRC. Verificamos também que, apesar do perfil metabólico ser diferente, alguns metabólitos como uréia, creatinina, ácido octadecanóico, ciclohexano, são compartilhados por todos os grupos. / Metabolomics is a quantitative analysis of biofluids and tissue for low molecular mass organic endogenous / exogenous metabolites. These representative small molecules found within a system cover a broad range of small molecules, such as carbohydrates, fatty acids, nucleotides, amino acids among many other classes of compounds. A few studies have been published focusing on the oral health of chronic kidney disease (CKD) patients. CKD, a public health problem worldwide, can be defined based on the presence of kidney damage or glomerular filtration rate (GFR) < 60 mL/min per 1.73m2 for 3 months, regardless of cause. On account of that, the aim of this study was to identify and interpret the role of saliva and urine metabolites of CKD individuals and their possible association with periodontitis (PD). Thirty adolescents and young adults, aged 12-18 years, with definite medical diagnosis of CKD and attending the CAPE (Center of Attendance for Special Needs Patients) of the Dental School and the Children Institute of the Medical School - University of São Paulo (USP), comprised the study. The control group was comprised of 30 clinically healthy individuals. Participants were asked to refrain from oral activities for 2 h prior to saliva collection. The first morning urine was also collected and both specimens were frozen at -80°C until assay. Periodontal evaluation was carried out by means of the simplified oral hygiene index (OHI-S), bleeding on probing and probing depth. All samples were analyzed in the Chemical Engineering Department of the Polytechnics School of USP, by means of the Gas-chromatography - mass spectrometry (GC-MS) technique. Statistical analyses were performed by means of the principal component analysis (PCA), Mann-Whitney and Kruskal-Wallis tests. The relative quantification showed higher levels of alanine (p<0.0001), glycine (p<0.0001), tyrosine (p=0.021), serine (p<0.0001), proline (p<0.0002) ,leucine (p<0.0003), citrulline (p<0.0001) and arginine (p<0.0002) for groups II and IV. The mean concentration of p-Cresol was also greater and statically significant when comparing groups II and IV. Groups with CKD displayed higher concentrations of carboxylic acids such as butyric acid, and also of dimetilarginine. In conclusion, it could be verified that both pathologies stimulate oxidative stress which synthetises metabolites such as butyric acid and L-proline which can potentialise the severity of CKD. Additionally, despite being possible to distinguish the metabolic profile of patients with PD, PD and CKD and only CKD from clinically healthy individuals, some of these metabolites such as acetic acid, urea, creatinine, octadecanoic acid and cyclohexane were shared among all groups.

Zhao Zheng. / "December 2000." / On t.p. "2" is subscript. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (p. 187-241). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Foi desenvolvido um método para determinar canabinóides (canabidiol, canabinol e delta-9-tetraidrocanabinol) no cabelo. Uma amostra de 10mg foi descontaminada com diclorometano, seguida de digestão alcalina, microextração em fase sólida por headspace (HS-SPME) e analisada por espectrometria de massa associada à cromatografia em fase gasosa (GC/MS). Os limites de detecção e de quantificação foram de 0,07 e 0,12 ng/mg, respectivamente, para todos canabinóides estudados. O método demonstrou ser simples, rápido, preciso e linear no intervalo de 0,12 a 12 ng/mg (r2 > 0,98). Amostras de cabelo de 8 usuários de Cannabis foram coletadas de pacientes provenientes de uma clínica dependentes pela equipe médica. O método mostrou-se eficiente em amostras de cabelos de usuários que faziam uso da droga pelo menos 10 vezes por semana. / A method was to develop to detect cannabinoids (cannabidiol, cannabinol and delta-9-tetrahydrocannabinol) in hair. A 10 mg of hair sample was descontaminated by dichloromethane followed by alkalin digestion, headspace solid-phase microextraction technique (HS-SPME) and analyzed by gas chromatography-mass spectrometry (CG/MS). The detection and quantitation limits were 0,07 and 0,12ng/mg respectively for all studied cannabinoids. The method proved to be simple, fast, precise and linear at the range of 0,12 to 12ng/mg (r2 > 0,98). Eight hair samples of Cannabis user were collected from patients at admittance from a dependence clinic by clinical staff. The method showed efficient in samples of users who use the drug at least 10 fold a week.

Metabolômica é a técnica que analisa quantitativamente metabólitos endógenos e exógenos de baixa massa molecular encontrados em biofluidos e tecidos. Estas pequenas moléculas representativas encontradas em um sistema biológico abrangem carboidratos, ácidos graxos, nucleotídeos, aminoácidos entre outras classes de compostos. Alguns estudos têm mostrado a importância da manutenção da saúde bucal para pacientes com doença renal crônica (DRC). DRC, um problema mundial de saúde pública, pode ser definida em função da presença de danos renais ou de uma taxa de filtração glomerular < 60 mL/min por 1.73m2 por 3 meses, independente da causa. Desta forma, o objetivo deste estudo foi identificar e interpretar a função de metabólitos salivares e de urina de pacientes com DRC e sua possível associação com a doença periodontal (DP). Trinta adolescentes e adultos jovens, 12-18 anos, diagnóstico médico definitivo de DRC, cadastrados no CAPE (Centro de atendimento a pacientes especiais) da Faculdade de Odontologia e no Instituto da Criança da Faculdade de Medicina - Universidade de São Paulo (USP), fizeram parte deste estudo. O grupo controle também foi composto por 30 indivíduos, porém, clinicamente saudáveis. Todos os participantes receberam informações prévias à coleta de urina e saliva. As amostras de saliva e a primeira urina da manhã foram coletadas e armazenadas a -80°C até a realização da análise. A análise periodontal foi realizada por meio do índice de higiene oral simplificado (OHI-S), sangramento à sondagem e profundidade de sondagem. Todas as amostras foram avaliadas no departamento de Engenharia Química da Escola Politécnica da USP por meio de análise de cromatografia gasosa acoplada ao espectrômetro de massa (GC-MS). As análises estatísticas foram realizadas por meio da análise de componentes principais (PCA), testes de Mann-Whitney e Kruskal-Wallis. A quantificação relativa de cada metabólito mostrou maiores concentrações estatisticamente significativas entre pacientes com DRC sem DP e com DRC e com DP, de alanina (p<0.0001), glicina (p<0.0001), tirosina (p=0.021), serina (p<0.0001), prolina (p<0.0002), leucina (p<0.0003), citrulina (p<0.0001) e arginina (p<0.0002). Os valores médios da concentração de p-Cresol também mostraram-se alterados para os mesmos grupos citados acima. Grupos com DRC mostraram concentrações alteradas de ácidos carboxílicos como ácido butírico e de dimetilarginina. Concluímos, portanto, que ambas as patologias estimulam o processo oxidativo sintetizando metabólitos como ácido butírico, L-prolina, dentre outros, os quais podem potencializar a severidade da DRC. Verificamos também que, apesar do perfil metabólico ser diferente, alguns metabólitos como uréia, creatinina, ácido octadecanóico, ciclohexano, são compartilhados por todos os grupos. / Metabolomics is a quantitative analysis of biofluids and tissue for low molecular mass organic endogenous / exogenous metabolites. These representative small molecules found within a system cover a broad range of small molecules, such as carbohydrates, fatty acids, nucleotides, amino acids among many other classes of compounds. A few studies have been published focusing on the oral health of chronic kidney disease (CKD) patients. CKD, a public health problem worldwide, can be defined based on the presence of kidney damage or glomerular filtration rate (GFR) < 60 mL/min per 1.73m2 for 3 months, regardless of cause. On account of that, the aim of this study was to identify and interpret the role of saliva and urine metabolites of CKD individuals and their possible association with periodontitis (PD). Thirty adolescents and young adults, aged 12-18 years, with definite medical diagnosis of CKD and attending the CAPE (Center of Attendance for Special Needs Patients) of the Dental School and the Children Institute of the Medical School - University of São Paulo (USP), comprised the study. The control group was comprised of 30 clinically healthy individuals. Participants were asked to refrain from oral activities for 2 h prior to saliva collection. The first morning urine was also collected and both specimens were frozen at -80°C until assay. Periodontal evaluation was carried out by means of the simplified oral hygiene index (OHI-S), bleeding on probing and probing depth. All samples were analyzed in the Chemical Engineering Department of the Polytechnics School of USP, by means of the Gas-chromatography - mass spectrometry (GC-MS) technique. Statistical analyses were performed by means of the principal component analysis (PCA), Mann-Whitney and Kruskal-Wallis tests. The relative quantification showed higher levels of alanine (p<0.0001), glycine (p<0.0001), tyrosine (p=0.021), serine (p<0.0001), proline (p<0.0002) ,leucine (p<0.0003), citrulline (p<0.0001) and arginine (p<0.0002) for groups II and IV. The mean concentration of p-Cresol was also greater and statically significant when comparing groups II and IV. Groups with CKD displayed higher concentrations of carboxylic acids such as butyric acid, and also of dimetilarginine. In conclusion, it could be verified that both pathologies stimulate oxidative stress which synthetises metabolites such as butyric acid and L-proline which can potentialise the severity of CKD. Additionally, despite being possible to distinguish the metabolic profile of patients with PD, PD and CKD and only CKD from clinically healthy individuals, some of these metabolites such as acetic acid, urea, creatinine, octadecanoic acid and cyclohexane were shared among all groups.

<p>U okviru doktorske disertacije su razvijeni i optimizovani postupci pripreme uzoraka hrane (žitarica, sirovina, poluproizvoda i prehrambenih proizvoda na bazi žitarica, voća i povrća) i stočne hrane, kao i simultano određivanje tropanskih i glikoalkaloida primenom gasne i tečne hromatografije uz maseno-spektrometrijsku detekciju. Razdvajanje alkaloida primenom gasne hromatografije je izvedeno na kapilarnoj koloni (HP-5MS UI), uz detekciju sa kvadrupolnom masenom spektrometrijom SIM tehnikom, u intervalu m/z 50&ndash;550 a.m.u. Pri optimizovanim uslovima postignuto je razdvajanje homatropina, atropina i skopolamina u vremenu od 12.75 min, pri čemu<br />tropin i anisodamin nisu mogli biti detektovani. Glikoalkaloidi nisu direktno mogli biti određivani gasnom hromatografijom usled njihove visoke molekulske mase i male isparljivosti. Za simultano određivanje tropanskih alkaloida (tropin, l-hiosciamin, atropin, skopolamin, homatropin i anisodamin) i glikoalkaloida (&alpha;-solanin i &alpha;-kakonin) validirana je brza i osetljiva multirezidualna LC&ndash;MS/MS metoda. Kori&scaron;ćena je disperzivna čvrsto-fazna ekstrakcija sa 0.5% mravlje kiseline u acotonitrilu/vodi (75:25, v/v), solima magnezijum sulfat, natrijum hlorid i natrijum citrat kao i C₁₈ sorbent. Analiti su razdvojeni na Chirobiotic V koloni, sa mobilnom fazom sastavljenom od 10 mM amonijum formata u voda/acetonitril (90:10, v/v) i metanol/acetonitril (50:50, v/v), me&scaron;anim u odnosu 20:80 (v/v). Detekcija komponenti je izvedena u pozitivnom elektrosprej modu (ESI+), kori&scaron;ćenjem reakcionog vi&scaron;estrukog monitoring akvizacionog moda (MRM). Optimizovana tečno hromatografska metoda je podrazumevala brz i jednostavan proces ekstrakcije, sa prinosom od 61-111% za pojedine alkaloide, dobru linearnost u &scaron;irokom opsegu (5-80 &mu;g/kg, r²=0.998), dobru selektivnost, robusnost i preciznost (CV &lt; 5%). Granica detekcije (LOD) za sve alkaloide je bila u opsegu od 0.74 do 0.79 ng/g dok se granica kvantifikacije (LOQ) kretala od 2.17 do 2.46 ng/g u svim žitaricama, izuzev za tropin u soji i lanenom semenu (LOD = 1.55 i LOQ = 4.91 ng/g). Pri analizi uzoraka sa trži&scaron;ta alkaloidi nisu detektovani u analiziranim uzorcima hrane, kao &scaron;to su: p&scaron;enica, raž, kukuruz, bra&scaron;no od me&scaron;anih žitarica, kukuruzno bra&scaron;no, biskvit i krekeri. Stočna hrana namenjena ishrani svinja i peradi je sadržala atropin, skopolamin, &alpha;-solanin i &alpha;-kakonin u koncentracionom opsegu od 3.6 do 21.7 ng/g. Atropin i skopolamin su detektovani u koncentracionom opsegu od 2.8 do 9.8 ng/g u hrani namenjenoj ishrani krava i zečeva, dok u hrani nemenjenoj ishrani konja i divljih životinja alkaloidi nisu detektovani. U analiziranim uzorcima voća i povrća (jabuka, kru&scaron;ka, avokado, mrkva, krastvac i paprika) po prvi put u ovom radu su detektovani glikoalkaloidi, &alpha;-solanin i &alpha;-kakonin. Koncentracija oba glikoalkaloida se kretala u opsegu od 0.3 do 15 ng/g. Sadržaj glikoalkaloida u krompiru i čipsu (8708.9-18794.7 ng/g) se nalazio u okviru preporučenog ukupnog sadržaja glikoalkaloida od 200 mg/kg (sirova odvaga) (FAO/WHO, 1999). Apsorpcija i translokacija alkaloida od strane p&scaron;enice u koren, listove i stabljiku je ustanovljena upotrebom atropina ¹⁴C. Utvrđeno je da biljka nakon 15 dana apsorbuje 4.30% i 2.28% atropina ¹⁴C za niži (13676 dpm/g soil) i vi&scaron;i (37203 dpm/g soil) sadržaj standarda sa kojim je zemlji&scaron;te spajkovano, redom. Količina apsorbovanog atropina se smanjivala tokom rasta biljke. Biljka starosti 90 dana je apsorbovala 0.38% i 0.21% atropina ¹⁴C za niži i vi&scaron;i sadržaj standarda, redom. Povećanje koncentracije supstance u zemlji&scaron;tu nije uticalo na dalje povećanje apsorpcije. Do nagomilavanja supstance je do&scaron;lo u listovima (83%) dok su niže koncentracije zabilježene u korenu (8.6%), stabljici (4.2%) i semenu (4.1%). U analiziranim uzorcima vode, koja je poticala od ispiranja zemlji&scaron;ta obogaćenog atropinom ¹⁴C, nakon 30 dana supstanca je detektovana u koncentraciji od 0.5%. Tokom vremena je ustanovljeno smanjenje ispiranja ove supstance (0.01% nakon 90 dana). Analiza uzoraka zemlji&scaron;ta nakon 30 i 60 dana je pokazala značajne adsorpcione osobine atropina, tako da je količina čvrsto adsorbovanog (neekstrahovanog) atropina iznosila 60% i 70%, redom. Zaostali atropin je bio stabilan i nakon 90 dana.</p> / <p>The methods of sample preparation have been developed and optimized for food (grains, raw materials, food products based on grains and fruits and vegetables) and feed analyses for the purpose of simultaneous determination of tropane and glycoalkaloids by gas and liquid chromatography hyphenated to mass spectrometry. Separation of alkaloids by gas chromatography was achieved by using capillary column HP-5MS UI. The alkaloids have been detected by using a quadrupole mass spectrometer inSIM mode for the range of m/z 50&ndash;550 a.m.u. Under optimised conditions, good separation of homatropine, atropine and scopolamine was achieved after 12.75 min, while tropine and anisodamine couldn`t be detected. Glycoalkaloids could not be analysed directly by gas chromatography due to their high molecular weight and low volatility. For simultaneous determination of tropane alkaloids (tropine, atropine, scopolamine, homatropine, anisodamine) and glycoalkaloids (&alpha;-solanine, &alpha;-chaconine) fast and sensitive multiresidue LC&ndash;MS/MS method was validated. In sample preparation dispersive solid phase extraction (DSPE) was performed with 0.5% formic acid in acetonitrile/water (75:25, v/v) and a mixture of magnesium sulphate, sodium chloride, sodium citrate and C18 sorbent. The analytes were separated by isocratic HPLC on a Chirobiotic V column with the mobile phase that consisted of 10 mM ammonium formate in water/acetonitrile (90:10, v/v) and methanol/acetonitrile (50:50, v/v), mixed in the ratio of 20:80 (v/v).<br />Compounds were detected in positive electrospray ionization mode (ESI+), using multi reaction monitoring (MRM). Optimised liquid-chromatographic method exhibited good linearity in the range 5-80 ng/g (r²=0.998). The method has shown to be specific, selective, accurate (recoveries from 61- 111%), precise (CV &lt; 5%) and rugged. Calculated limits of detection (LOD) for all alkaloids were in the range 0.74-0.79 ng/g, while the limits of quantitation (LOQ) were in the range 2.2-4.9 ng/g in all grains, except for tropine in soybean and linseed (LOD = 1.55 and LOQ = 4.91 ng/g). The proposed method was applied in the analyses of samples obtained from local supermarkets. The alkaloids were not detected in following food samples:<br />wheat, rye, maize, mixed grain flour, corn flour, biscuits and crackers. The feeds for pigs and chicken were the most contaminated with atropine, scopolamine, &alpha;-solanine and &alpha;-chaconine with the contents of alkaloids in the range of 3.6 to 21.7 ng/g. Atropine and scopolamine were detected in cattle and rabbit feed in concentrations ranging from 2.8 to 9.8 ng/g, while in feed for horses and wild animals none of the target alkaloids were detected. Conducted research reports for the first time the presence of glycoalkaloids, &alpha;-solanine and &alpha;-chaconine in fruit and vegetable samples (apple, pear, avocado, carrot, cucumber and paprika). The concentrations of these alkaloids were in the range of 0.3 to 15 ng/g. The content of glycoalkaloids in potato and chips complied with the recommended content of total glycoalkaloids concentration of 200 mg/kg (raw weight) (FAO/WHO, 1999). Absorption and translocation of alkaloids in wheat (roots, leaves, stem) was determined by using atropine ¹⁴C. It was found that young wheat after 15 days absorbed approximately 4.30% and 2.28% of atropine ¹⁴C for low (13676 dpm/g soil) and high (37203 dpm/g soil) spiked levels in soil, respectively. Increase in the spiked concentration in the soil did not affect higher absorption of atropine ¹⁴C in wheat. The highest accumulation of atropine ¹⁴C was observed in the leaves (83%) while lower<br />concentrations were detected in the roots (8.6%), stems (4.2%) and seeds (4.1%). In collected water samples during the soil leaching, atropine ¹⁴C was detected in the concentration of 0.5%. Leaching decreased with the time (0.01% after 90 days). Analyses of soil samples after 30 and 60 days showed strong adsorption of atropine to the soil and quantity of adsorbed atropine was 60% and 70%, respectively. Adsorbed atropine in the soil was stable after 90 days.</p>

Os métodos convencionais para a determinação de fármacos em fluidos biológicos baseiam-se em técnicas cromatográficas e imunoquímicas. O tratamento prévio de amostras biológicas, o qual abrange as etapas de extração, pré-concentração e “clean-up", tem sido requerido nas análises de fármacos, para aumentar a sensibilidade e seletividade analítica. No entanto, nos últimos anos, com o avanço das técnicas instrumentais, diversas técnicas têm sido avaliados para a análise de diferentes fármacos em fluidos biológicos, destacando-se entre elas a Microextração em Fase Sólida (SPME) e a Cromatografia Líquida acoplada a Espectrometria de Massas (LC/MS). A SPME apresenta uma série de vantagens em relação às técnicas de extração tradicionais, ou seja: não requer instrumentação analítica sofisticada, não utiliza solvente orgânico, permite automação das análises, a reutilização das fibras extratoras e integra em um único sistema, a extração, concentração e introdução da amostra no sistema cromatográfico. Neste trabalho, foi desenvolvida uma interface versátil e de baixo custo, que permite o acoplamento das técnicas SPME-LC/MS para análise dos fármacos antidepressivos tricíclicos e anticonvulsivantes. O planejamento fatorial empregado mostrou ser uma ferramenta estatística importante e simples, sendo obtido mais informações com um número menor de experimentos, avaliando não só os efeitos principais como os efeitos de interação de todas as variáveis nas respostas. As condições cromatográficas otimizadas foram adequadas para a análise por LC/MS. Os níveis de detecção alcançados ressaltam a importância e destaque da técnica de cromatografia líquida de alta eficiência acoplada à espectrometria de massas (LC/MS). O método desenvolvido, tanto para os fármacos antidepressivos tricíclicos como para os anticonvulsivantes, mostrou especificidade, precisão, linearidade e limite de quantificação adequado para a análise. / Conventional methods used for the determination of drugs in biological fluids are based on chromatographic and immunochemical techniques. The biological samples treatment - which includes extraction, pre-concentration and clean up steps – has been required in drugs analysis in order to increase both analytical sensitivity and selectivity. Nevertheless, lately, within the advancements in instrumentation, different techniques have been evaluated for the analysis of different drugs in biological fluids, such as: solid phase microextraction (SPME) and liquid chromatography coupled to mass spectrometry (LC/MS). SPME presents many advantages towards the conventional extraction techniques (soxhlet, LLE and SPE), which include: use of simple analytical instrumentation, analysis automation, reuse of extractor fibers and integration of extraction, concentration and sample introduction in the same chromatographic system. In this work, a versatile and low cost interface was developed, which allows the coupling of SPME-LC/MS techniques to tricyclic antidepressants and anticonvulsivant drugs analysis. The employed factorial design has shown to be a simple and useful statistical tool. With this device more information could be obtained with fewer experiments by evaluating not only the main interaction effects but also the interaction effects of all variables on the results. The optimized chromatographic conditions were adequate for LC/MS analysis. The obtained detection levels highlight the importance of high performance liquid chromatography coupled to mass spectrometry (LC/MS). The developed method, for both tricyclic antidepressants and anticonvulsivants drugs, has presented specificity, accuracy, linearity and adequate limit of detection for this analysis.

<p>Liquid chromatography – mass spectrometry (LC-MS) methods were developed for the analysis of positron emission tomography (PET) radiotracers in biological matrices. Additionally, radiotracer chemistry was explored as an analytical tool for supporting LC-MS method development and imaging molecular interactions in miniaturised chemical analysis systems.</p><p>Conventional radiodetection methods can offer high sensitivity in the analysis of radiotracers in biological matrices, although with the short half-life of PET tracers, this mass sensitivity decreases rapidly with time. This limits the time frame for analysis, and may compromise the precision and accuracy of the later measurements. Performing LC-MS analysis of the dominant stable isotope form of the tracer removes such time restrictions.</p><p>An LC-MS/MS method was developed for determination of the tracer flumazenil in human plasma, with high inter-assay precision (RSD < 7%) and accuracy (95 – 104%). The method was applied in a multiple scan PET study where the plasma concentration spanned from 0.07 to 0.21 nM. The method removed the time restrictions associated with radiodetection methods and thus provided the opportunity of analysing a greater number of samples than would have been possible with radioanalysis.</p><p>Furthermore, an LC-MS/MS method was developed that provided an efficient metabolic screening tool of potential PET tracers, whereby the substrates could be collected directly from 11C-labelling batches. This permitted repeated incubation experiments without the need of repeated labelling syntheses. A para-methoxy-benzamide analogue of the radiotracer WAY-100635 was thus identified as a potential tracer with improved metabolic stability. Additionally, a capillary LC-MS method was developed with rapid (0.75 min) and efficient (> 99%) on-line high flow-rate extraction for determination of metabolic stability of PET radiotracers.</p><p>Finally, the concept of radionuclide imaging of miniaturised chemical analysis systems was demonstrated with the direct study of interactions within capillary extraction columns and microchannels moulded in a plastic CD and poly(dimethylsiloxane).</p>

Liquid chromatography – mass spectrometry (LC-MS) methods were developed for the analysis of positron emission tomography (PET) radiotracers in biological matrices. Additionally, radiotracer chemistry was explored as an analytical tool for supporting LC-MS method development and imaging molecular interactions in miniaturised chemical analysis systems. Conventional radiodetection methods can offer high sensitivity in the analysis of radiotracers in biological matrices, although with the short half-life of PET tracers, this mass sensitivity decreases rapidly with time. This limits the time frame for analysis, and may compromise the precision and accuracy of the later measurements. Performing LC-MS analysis of the dominant stable isotope form of the tracer removes such time restrictions. An LC-MS/MS method was developed for determination of the tracer flumazenil in human plasma, with high inter-assay precision (RSD &lt; 7%) and accuracy (95 – 104%). The method was applied in a multiple scan PET study where the plasma concentration spanned from 0.07 to 0.21 nM. The method removed the time restrictions associated with radiodetection methods and thus provided the opportunity of analysing a greater number of samples than would have been possible with radioanalysis. Furthermore, an LC-MS/MS method was developed that provided an efficient metabolic screening tool of potential PET tracers, whereby the substrates could be collected directly from 11C-labelling batches. This permitted repeated incubation experiments without the need of repeated labelling syntheses. A para-methoxy-benzamide analogue of the radiotracer WAY-100635 was thus identified as a potential tracer with improved metabolic stability. Additionally, a capillary LC-MS method was developed with rapid (0.75 min) and efficient (&gt; 99%) on-line high flow-rate extraction for determination of metabolic stability of PET radiotracers. Finally, the concept of radionuclide imaging of miniaturised chemical analysis systems was demonstrated with the direct study of interactions within capillary extraction columns and microchannels moulded in a plastic CD and poly(dimethylsiloxane).

In this study, the Persistent Organic Pollutants (POPs) specifically / 17 Organochlorine Pesticides (OCPs) and 19 Polycyclic Aromatic Hydrocarbons (PAHs) were evaluated in the sediment samples of Balikesir (Ikizcetepeler) Dam Lake. Sixteen sampling points were chosen for determination of concentrations of OCPs and PAHs After ultrasonic bath extraction of the sediment samples GC-MS was used as analytical tool. Extraction efficiencies changes from 63.8 to 87.4% depending on the type of the POPs. Average OCP concentration was found in the range of 3.33-379 &micro / g/kg a, average PAH concentration was found in the range of 3.28-32.9 &micro / g/kg. Pollution maps regarding OCP and PAH distributions were drawn and the correlation between these two pollutant types was investigated. The quality control (QC) and quality assurance tests were applied by the analysis of standard reference materials (SRMs), surrogate standards and analysis replicates.

As agrarian society developed, the most fertile soils able to sustain the nutritional requirements needed for high crop yield were assigned to farming, while the more penurious soils were left to uphold the forest ecosystems. Some temperate forests are developed on acidic soils considered to be nutrient poor, as much of the inorganic nutrients are entrapped in poorly weatherable soil minerals and not easily accessed by plant roots. In an undisturbed ecosystem, the largest contribution of available nutrients comes from the recycling of organically bound nutrients via the decomposition of dead plant material. If biomass is removed, for instance with a more intensified exploitation of the forest ecosystems including whole tree harvesting, this source of nutrients is consequently decreased. The importance of soil mineral weathering as a source of nutrients, and especially that promoted by soil biota, is thereby emphasized. This thesis addresses biotic parameters associated with mineral weathering. Different aspects of soil solution sampling strategies and analysis of different organic ligands as well as biomarkers for the estimation of fungal biomass were investigated. These chemical parameters were also evaluated as indicators of microbial activity in relation to mineral nutrient availability in soil. With the assumption that the current nutrient status of a soil will affect the microbial interest of certain minerals as sources of inorganic nutrients, a mineral amendment trial was performed in a Swedish boreal forest soil. Overall, the amended soil presented good nutrient status, but with a possible shortage of iron. Due to this, it was hypothesized that the amended mineral with the highest iron content i.e. biotite would cause an elevation of microbial activity in its vicinity when compared to the bulk soil. The level of microbial activity in the vicinity of the amended minerals was evaluated via quantification of organic acids and siderophores, as well as estimation of fungal biomass and enzymatic activity. The highest microbial activity was measured for the O horizon of the investigated podzol, although nothing indicated an elevated association with the amended minerals. In the E horizon, however, elevation in microbial activity was observed in the vicinity of the biotite mineral when compared with bulk soil, although only a few of the investigated parameters differed significantly when evaluated separately.   To enable this study, a highly sensitive analytical method employing liquid chromatography and mass spectrometry was developed to quantify a number of hydroxamate siderophores. On-line pre-concentration enabled detection of these organic ligands in the pico-molar range – a necessity when analyzing natural samples. Furthermore, an analytical method was developed for the estimation of fungal biomass via quantification of chitin-derived glucosamine, which also employed liquid chromatography and tandem mass spectrometry. Unlike currently available methods, the one presented in this thesis did not involve analyte derivatization, which resulted in high sample throughput while simultaneously avoiding complications involved with the additional derivatization procedure. The distribution of a group of organic ligands known as aromatic low molecular mass organic acids was also studied in a boreal forest podzol soil. Different sampling and samples preparation techniques, namely tension-lysimeters, soil centrifugation and liquid-soil extraction, were compared when analyzing soil solution components. Significant differences in analyte amount and species type were found between these sampling techniques. Some of the differences could be accounted for by variation in soil composition at different depths of the investigated podzol, but others could be attributed to structural differences within the studied analyte group. This clearly illustrated the intricacy of sampling and analysis when working with a sample matrix as complex and diverse as soil. As previously, liquid chromatography and mass spectrometry was used to quantify the analytes of interest. A highly sensitive analytical method was developed that was able to detect eleven aromatic low molecular mass organic acids in the nano-molar range. High selectivity was ensured by applying multiple reaction monitoring enabled by collision induced fragmentation of the analytes. / FORE