This study focuses on a general method that has been developed for the identification of both polar- and nonpolar pesticidespolar pesticides in a known solution from EPA 8151 Herbicide acid mix by Merck including the ordered non-polar pesticide Prosulfocarb. The EPA-solution contains 16 analytes that has been completely identified when derivatized and spiked in acetone. The solution has also been spiked in blood samples, resulting in five calibration solutions in the range of 0,01 – 2,5 µg/g, followed by quantification. Identification of dinoseb and bentazone, spiked in blood, failed whereas the remaining 145 analytes were identified. The method uses headspace (HS) solid phase microextraction (SPME) in combination with gas chromatography (GC) with mass spectrometry (MS) in both scan and selected ion monitoring mode. A standard extraction- and derivatization procedure has been performed for the analysis of alcohols, phenols, and carboxylic acids with help from a protocol regarding the analysis of ethylene glycol in blood. Samples were introduced on the column with splitless injection where 1 µl were injected with an injector temperature of 250oC. Effective separations were achieved by using GS-GasPro PLOT-column (30 m x i.d. 320 µm x df 0 µm) in combination with a temperature programme that started at an initial temperature of 80oC (1 min) that increased by 10oC/min up to 280oC (1 min). The limit of detection (LOD) for the pesticides, spiked blood, were 0,01 – 2,5 µg/g where the lowest limit of 0,01 µg/g meant difficult identification whereas a greater identification was made at 0,05 µg/g. No identification was succeeded for the most polar substances in the forms of amines and amides in combination with carboxylic acid. Identification was however made for the less polar pesticides in the forms of alcohols, phenols, and carboxylic acids. The method must be further developed to identify the highly polar pesticides in different chemical classes. The current method can be used in occurring intoxications and in autopsy cases.

No description available.

Also aged bottles are safer to use than new bottles because their chemical leaching was found to be lower than that of new bottles. This study recommends the reassessment of the absence of international guidelines for acetaldehyde in water and foods. The study also recommends that the amount of acetaldehyde that can be added to soft drinks as flavouring agent should be below the specific migration limit (SML) for migration of acetaldehyde from PET bottle into bottle contents. This is essential since the SML was designed to ensure that exposure to acetaldehyde, as a result of intake of bottled water and soft drinks in PET bottles, is below the tolerable daily intake (TDI) for acetaldehyde. As antimony was reported to go beyond the safe limits in some Nigerian bottled water and soft drinks after 11 months of storage this study discourages the use of bottle contents stored for a very long time.

Polycyclic aromatic hydrocarbons (PAHs) and nitrogen-containing polycyclic aromatic compound (N-PAC) are widespread toxic pollutants in environments. The fate of PAHs and N-PACs are of great concern because some of these compounds were identified as caricinogenic, mutagenic and teratogenic compounds. As described in literature, dissolved organic matter (DOM) is an important factor in control of their fate; however, the binding behaviors between these compounds and DOM are still not fully understood. The binding constants (KDOC) between humic substances and one selected N-PAC, benzo[h]quinoline, were measured at varying pH levels using fluorescence quenching (FQ) method. As fluorescence characteristics of benzo[h]quinoline change with pH, determination required two optimum sets of excitation and emission wavelength pairs. A simple mixing model was proposed and used to eliminate the inherent fluorescence interference between benzo[h]quinoline (BQ) and its protonated form, benzo[h]quinolinium (BQH+), and to deduce Kmix which represents the overall binding as the sum of that for the individual analogs. The characteristics of humic substances, especially their hydrophobicity and aromaticity, established by principal components analysis of structural and elemental compositions, were the main determinants of their binding affinity with both benzo[h]quinoline and benzo[h]quinolinium (KBQ and KBQH+) across a range of pH values. Hydrophobic interaction is likely to control the binding between humic substance and benzo[h]quinoline and benzo[h]quinolinium, in lower and higher pH ranges (pH<3, pH>6). In contrast, cation exchange seems to control on the binding affinity of benzo[h]quinolinium in the middle range of pH. Determination of PAH concentration is quite essential for investigating the fate of PAHs in environments. Microwave-assisted headspace solid-phase microextraction (MA-HS-SPME) with a polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber was applied as a single step prior to determination of PAH concentrations in water using GC-MS. To optimize the extraction efficiency of PAHs by MA-HS-SPME, the influence of various parameters, including temperature, duration of thermal desorption, microwave irradiation power and duration, and the temperature of the circulating cooling water system, was studied. The proposed method was demonstrated applicable to environmental water samples. In addition, DOM matrix effect did not influence the determination and extraction efficiency of PAHs. Although the proposed simple mixing model can eliminate the fluorescent interference of hydrophobic organic compounds with acid-base pair forms, it is still limited in using for correcting the KDOC measurement of more than two fluorescent compounds simultaneously. A new alternative protocol, complexation-flocculation combined with MA-HS-SPME/GC-MS method, was proposed to determine the binding constants of seleted PAHs to humic substances. The results obtained are comparable with KDOC data reported in literatures. CF-MA-HS-SPME/GC-MS provides some advantages over other methods, such as applicable not limited to fluorescent compounds, faster in determination and capable in measuring varieties of compounds simultaneously.

Methylone, Ethylone, Methylenedioxypyrovalerone (MDPV), and α-Pyrrolidinopentiophenone (α-PVP) collectively referred to as bath salts are a new trend of illicit substances known as synthetic cathinones. Designed by chemically modifying the core structure of the compound cathinone, synthetic cathinones became prevalent within the United States around the mid-2000s. As a cheap and less controlled alternative to methylenedioxymethamphetamine (MDMA, ecstasy), it has become heavily abused, prompting emergency scheduling by federal regulators. Although regulations have been placed to halt incoming traffic of these drugs, lack of ground efforts still leave a large percentage of bath salts available. This study is two-fold, as it seeks to develop an extraction method for the development of Volatile Organic Compound profiles associated with various synthetic cathinones; and also determine the odorant used for canine recognition. The initial goal of this dissertation was to develop an extraction method to characterize various cathinone derivatives. The present study concluded that by employing a Polydimethylsiloxane Divinylbenzene (PDMS/DVB) coated fiber along with complimentary soft ionization techniques, the volatile components and all parent drugs could be identified within sixteen synthetic cathinone cases. The second goal of the dissertation was to assess and enhance the detection capabilities of narcotic detection teams. Canine field detection is routinely used to stop the increasing distribution influx of drugs into the United States that go undetected by standard procedures currently employed. Although currently canines can detect a multitude of drugs including heroin, cocaine, MDMA, and methamphetamine; this study revealed that more than ten canine teams (throughout south Florida) were not able to detect the presence of synthetic cathinones with current training material. While concerns have grown concerning the safety and reliability of canines being trained on various illicit substances, this research aimed to develop a safe, efficient, controlled alternative to training any canine for detection in the form of a Controlled Mimic Permeation System (COMPS). Field examination concluded that 3,4-methylenedioxypriophenone was the odorant responsible for the canine recognition of the cathinone derivative odor. Therefore a mimic training aid was developed and deployed within the field to enhance the detection capabilities of various canine teams.

Polyethylene terephthalate (PET) is an excellent material for bottling water, beverages, edible oils and other liquids because it is light, tough and transparent. PET bottles are also extensively reused for storage of drinking water, beverages and other liquids and for solar disinfection of microbiologically unsafe drinking water in the tropics. In spite of the usefulness of PET bottles earlier works have reported leaching of antimony and acetaldehyde from the bottle matrix into the liquid contents. Both antimony trioxide and acetaldehyde belongs to Group 2B (possible carcinogens) in the International Agency for Research on Cancer (IARC) carcinogen classification. Additionally acetaldehyde associated with alcoholic beverages (derived from alcoholic beverage and formed endogenously) has recently been upgraded to IARC Group 1 carcinogen (carcinogenic to humans). The research aims to assess the pattern and extent of antimony and acetaldehyde migration from British and Nigerian polyethylene terephthalate bottles into bottle contents under typical use and reuse conditions. The research compares the assessed extents of migration with the current regulations to determine whether the maximum acceptable levels of antimony and acetaldehyde are being exceeded and whether current regulations might need to be reassessed. To achieve these goals the pattern and extent of PET bottle use and reuse in Britain and Nigeria were appraised through survey. The survey revealed that new bottles with contents are typically stored prior to use for periods ranging between one and 7 days, with Nigerians storing for longer periods than British respondents. However storage of up to one year was reported. The extent of bottle reuse was high and similar for the two countries. Nevertheless Nigerian respondents reuse bottles for longer periods than British respondents. The survey findings together with relevant literature were used to design laboratory experiments that assessed the extent of antimony and acetaldehyde migration from PET bottles into water/beverages. A total of 82 brands of bottled water and soft drinks in plastic and glass bottles and in cartons were collected. A few samples from Nigeria in plastic pouches were collected. Materials used in bottling including glass and plastic bottle materials, metal and plastic bottle cap materials and plastic cap lining materials were collected. All samples were collected in supermarkets and shops in Britain and Nigeria except drinking water from taps which was collected in Britain only. Some bottles were aged for the purpose of studying the impact of bottle aging on chemical migration. Other bottles were stored with their contents to study the impact of long term storage of bottle contents on chemical migration. Energy dispersive X-ray spectrometry (EDX) and Raman spectroscopy were used to characterise PET bottle material and other materials associated with water and soft drink bottling. Antimony and other trace metals in water and soft drinks were determined using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Antimony content of PET and other plastics was determined by microwave digestion and ICP-MS. Acetaldehyde content of water and soft drinks and PET were determined using headspace gas chromatography with flame ionisation detection (GC-FID). Accuracy and precision for determination of antimony and other trace elements in bottle materials and bottle contents were good as recoveries were around 100% and coefficients of variation were less than 15% for all analysis types. Accuracy and precision for determination of acetaldehyde in bottle materials and bottle contents were also good as recoveries were around 100% and coefficients of variation were less than 15% for all analysis types. Impact of long term storage, elevated temperatures, bottle thickness, carbonation, bottle aging and bottle size on migration of antimony and acetaldehyde were also assessed. All plastic bottle materials analysed were found to be PET. Bottle cap materials were either polyethylene or polypropylene. All plastic cap lining materials from Britain and some from Nigeria were found to be ethylene vinyl acetate/polypropylene copolymer. Plastic cap lining materials from some Nigerian soft drinks were identified as polyvinyl chloride. Glass bottle materials analysed were found to be soda-lime glass. Metal bottle caps were identified as tinplate, tin-free-steel coated with chromium or aluminium coated with chromium. The antimony concentration in 32 PET bottle materials from Britain and Nigeria were similar and ranged between 177 and 310 mg/kg with an average of 250±30 mg/kg. The concentration agrees well with the industry reported concentration of between 150 and 350 mg/kg. The concentration of residual acetaldehyde in 25 fresh PET bottle materials from Britain and Nigeria ranged between 0.95 and 12.52 µg/g. The average concentration in British and Nigerian soft drinks PET materials are 4.76 and 2.17µg/g respectively. Concentration of residual acetaldehyde was higher in soft drinks and still water PET materials than in sparkling water materials. The concentration of residual acetaldehyde decreases as the bottle wall material becomes older. Also the thinner the bottle walls the lower the concentration of residual acetaldehyde. Antimony concentration in 47 freshly purchased British bottled water and soft drinks ranged between 0.03 and 6.61µg/L with only one sample going above the EU acceptable limit. Concentrations of other trace elements measured were low except titanium which was detected at part per million levels in soft drinks. Lead content of a Nigerian soft drink in glass bottle stored for 2 months was above the EU acceptable limit for lead. At realistic temperatures of 40 and 60°C antimony concentration in the water remained below the EU acceptable limit even after 48 hours of exposure but the concentration exceeded the limit for most exposures at 80°C. Concentration of antimony in some Nigerian bottled water and soft drinks was above the EU limit after 11 months of storage at room temperature. Aged bottles leach lower amount of antimony than new bottles. Similarly larger bottles leach lower amount of antimony than smaller bottles. The average acetaldehyde concentrations found in British fruit juices, carbonated soft drinks, sparkling water and still water were 5113, 1458, 22 and 8 µg/L respectively. Acetaldehyde was not detected in water bottled in glass. The concentration of acetaldehyde in five fruit juice samples in PET bottles and carton was beyond the EU specific migration limit (SML) of 6mg/kg. Also the tolerable daily intake of acetaldehyde could be exceeded as a result of intake of some soft drinks and fruit juices. Acetaldehyde content in soft drinks increase with storage but the increase cannot be accounted for by the residual acetaldehyde in PET. Acetaldehyde was found to be outgassing from some bottles. It was also found to be capable of migrating from soft drinks into bottle wall. Without replenishment the concentration of acetaldehyde in solution decreases with time. The use of PVC cap lining in Nigeria as found in this study is a cause for concern as PVC is associated with health risk issues. The study recommends actions to ensure that antimony in fruit juices and other bottled products remain within the regulatory standard from bottling to consumption for the purpose of safeguarding the health of consumers. Glass used in bottling should be well scrutinized to ensure that it does not contain high levels of lead or other chemical substances that can cause harm to consumers through migration into contents. PET bottles can safely be used for solar water disinfection without the risk of antimony intake at concentrations above safe limits as water temperature achievable as the result of the technique doesn¿t go beyond 60°C. Also aged bottles are safer to use than new bottles because their chemical leaching was found to be lower than that of new bottles. This study recommends the reassessment of the absence of international guidelines for acetaldehyde in water and foods. The study also recommends that the amount of acetaldehyde that can be added to soft drinks as flavouring agent should be below the specific migration limit (SML) for migration of acetaldehyde from PET bottle into bottle contents. This is essential since the SML was designed to ensure that exposure to acetaldehyde, as a result of intake of bottled water and soft drinks in PET bottles, is below the tolerable daily intake (TDI) for acetaldehyde. As antimony was reported to go beyond the safe limits in some Nigerian bottled water and soft drinks after 11 months of storage this study discourages the use of bottle contents stored for a very long time. / Commonwealth Scholarship Commission in the United Kingdom

Данная работа предполагает разработку методики анализа остаточных органических растворителей (ООР) в субстанциях натрия 3,8-диэтоксикарбонил-4-оксо-4Н-пиразоло[5,1-c][1,2,4]триазинид моногидрата (AB-19) и натрия 7-метилтио-4-оксо-3-циано-4Н-[1,2,4]триазоло[5,1-c][1,2,4]триазинида тригидрата (MNR-857). Анализ литературных данных показал, что наиболее предпочтительным методом определения ООР является метод газожидкостной хроматографии с парофазным вводом пробы. Для определения целевых аналитов в исследуемых субстанциях рассмотрены схемы синтеза и строение соединений, и определено, что образцы могут содержать органические растворители II (гексан, пиридин, метанол) и III (этанол, этилацетат, 2-пропанол) классов опасности. Однако опытные данные показали наличие в образцах субстанций только этанола и пропан-2-ола. В связи с этим проводили количественное определение только указанных растворителей. На основе литературных данных были определены исходные условия проведения хроматографического анализа. На практике исходная методика была скорректирована: изменение массы навески, разведения образца, времени выдерживания виалы, установление диапазона концентраций применения методики и метода количественного определения. Разработанную методику анализа подвергали испытаниям на пригодность по таким показателям как специфичность, линейность, предел количественного определения, сходимость, промежуточная прецизионность и правильность. Согласно проведенным исследованиям была доказана достоверность и надежность получаемых с использованием данной методики результатов. Количественное определение ООР с помощью разработанной методики в образцах субстанций AB-19 (3 партии синтеза) и MNR-857 (5 партий синтеза) подтвердило их соответствие требованиям ОФС.1.1.0008.15 по показателю остаточные органические растворители (не более 0,5 % для растворителей III класса опасности). / This paper discusses the development of a method for assay of residual organic solvents in substances in substances such as sodium 3,8-diethoxycarbonyl-4-oxo-4H-pyrazolo[5,1-c][1,2,4]triazinide monohydrate (AB-19) and sodium 7-methylthio-4-oxo-3-cyano-4H-[1,2,4]triazolo[5,1-c][1,2,4]triazinide trihydrate (MNR-857). An analysis of the literature data showed that the most preferred method for determining residual organic solvents is headspace gas-liquid chromatography. To determine the target analytes in the studied substances, synthesis schemes and the structure of compounds are considered. Thanks to this, it was decided that the samples might contain organic solvents of hazard classes II and III. Class II includes hexane, pyridine, methanol, and сlass III includes ethanol, ethyl acetate, 2-propanol. However, experimental data showed the presence of only ethanol and propan-2-ol in the samples of substances. In this regard, an assay was carried out only for these two solvents. Based on literature data, the initial conditions for the chromatographic analysis were determined. The original method was adjusted by changing the test portion of sample, diluting the samples, the holdup time of the vial, as well as by establishing ranges of concentrations and the method of quantitative measurement. The developed analysis method was tested for suitability by such indicators as specificity, linearity, limit of quantification, repeatability, intermediate precision, and accuracy. According to the research, it was demonstrated that the analytical technique is acceptable for solving the task. The residual organic solvents were quantified using the developed procedure for three batches of synthesis of substance AB-19 and for five batches of synthesis of substance MNR-857. The percentage of residual organic solvents in all samples was less than 0.5%. Thus, the results obtained satisfy the requirements of the article OFS.1.1.0008.15 of the State Pharmacopoeia of the Russian Federation in terms of residual organic solvents.

No description available.

<p dir="ltr">The detection of explosives and explosive devices based upon the volatile compounds they emit is a long-standing tool for law enforcement and physical security. Towards that end, solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) has become a crucial analytical tool for the identification of volatiles emitted by explosives. Previous SPME studies have identified many volatile compounds emitted by common explosive formulations that serve as the main charge in explosive devices. However, limited research has been conducted on initiators like fuses, detonating cords, and boosters. In this study, a variety of SPME fiber coatings (i.e., polydimethylsiloxane (PDMS), polydimethylsiloxane/divinylbenzene (PDMS/DVB), divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS), carboxen/polydimethylsiloxane (CAR/PDMS), and polyacrylate (PA)) were employed for the extraction and analysis of volatiles from Composition C-4 (cyclohexanone, 2-ethyl-1-hexanol, and 2,3-dimethyl-2,3-dinitrobutane (DMNB)) and Red Dot double-base smokeless powder (nitroglycerine, phenylamine). The results revealed that a PDMS/DVB fiber was optimal. Then, an assortment of explosive items (i.e., detonation cord, safety fuse, slip-on booster, and shape charge) were analyzed with a PDMS/DVB fiber. A variety of volatile compounds were identified, including plasticizers (tributyl acetyl citrate, N-butylbenzenesulfonamide), taggants (DMNB), and degradation products (2-ethyl-1-hexanol). </p><p dir="ltr">Taggants, like DMNB, are one of the pivotal components added to explosives. These distinctive chemical markers, deliberately introduced during manufacturing to facilitate the identification of explosives, are commonly detected using SPME GC- MS, but their quantitation remains underexplored. To address this, we investigated total vaporization headspace (TV- HS) GC- MS for quantifying taggants in the headspace of Composition C4. Factors effecting the extraction of DMNB, such as shape and age of the sample, and surface depletion, were also examined. The results revealed that the shape of the sample did not affect the amount of DMNB in the headspace but the older the sample, the more DMNB was detected in the headspace. Surface depletion was also seen in samples that were exposed to air for more than one week. Then calibration curves with calibrants of DMNB in acetone were established for quantitation. The average concentration of DMNB in the headspace was determined to be 125 parts per million (ppm).</p><p><br></p>

O álcool é uma das substâncias psicoativas mais consumidas mundialmente e seu uso por mulheres em idade reprodutiva, em particular, tem representado grande preocupação por parte de especialistas e da sociedade em geral. Apesar dos efeitos adversos associados ao ato de ingerir bebidas alcoólicas durante a gestação ser bastante documentados e conhecidos, sabe-se que uma parcela de mulheres grávidas tem dificuldades em abandonar o hábito. O consumo excessivo de álcool durante a gravidez tem sido associado com a síndrome fetal pelo álcool (FAS), caracterizada por crianças com dificuldades comportamentais e de aprendizado. Entretanto, devido ao sentimento de culpa e medo de ações punitivas, mulheres raramente admitem terem utilizado álcool durante a gestação. Como resultado, uma série de marcadores biológicos tem sido estudada para se diagnosticar a exposição fetal ao etanol. Dentre os marcadores utilizados estão os ésteres etílicos de ácidos graxos (FAEE), que podem ser detectados em amostras de mecônio de recém-nascidos. No presente trabalho, um método analítico foi desenvolvido visando a detecção de oito FAEEs em amostras de mecônio e aplicada em amostras coletadas de recém-nascidos cujas mães admitiram ou não o uso de etanol durante a gestação. A microextração em fase sólida por Headspace (HS-SPME), uma técnica de preparação de amostras relativamente recente, foi utilizada para análise. Os FAEEs foram identificados e quantificados por cromatografia gasosa/espectrometria de massas (GC/MS), operado no modo de ionização química. Os correspondentes ésteres etílicos deuterados foram sintetizados e utilizados como padrão interno. Os limites de quantificação (LOQ) obtidos foram abaixo de 150 ng/g e limites de detecção (LOD) foram abaixo de 100ng/g para todos os analitos. O método mostrou boa linearidade na concentração estudada (LOQ-2000ng/g), com coeficiente (r2) melhor que 0.98. Os valores de precisão apresentaram coeficientes de variação menores que 15% para todos os FAEEs estudados. Quando o método foi aplicado em amostras de mecônio, foi possível detectar níveis de alguns FAEEs de recém-nascidos não suspeitos a exposição fetal ao etanol. / Alcohol is the main psychoactive drug consumed worldwide and its increasing use by young women has been a great problem point out by specialists in the subject. Although the adverse effects associated to the habit of drinking alcoholic beverages during gestation being very much documented, it is known that a considerable number of pregnant women have difficulties to abandon the habit. Excessive alcohol use during pregnancy has been associated with Fetal Alcohol Syndrome (FAS) characterized by children with cognitive and behavioral disorders. However, because of denial, embarrassment and fear, maternal reports of gestational use of alcohol are often inaccurate. Consequently, a series of biomarkers have been studied to diagnose fetal exposure to alcohol. Recently, fatty acid ethyl esters (FAEE) have been studied as biomarkers found in meconium of neonates exposed in utero. In the present work, an analytical method was developed aiming the detection of eight FAEEs in meconium samples and applied to real specimens collected from newborns whose mothers admitted or not the use of alcohol during pregnancy. Headspace solid-phase microextraction (HS-SPME), a relatively recent sample preparation technique, was used for analysis. FAEEs were identified and quantified by gas chromatography/mass spectrometry (GC/MS), operated in chemical ionization mode. The corresponding deuterated ethyl esters were synthesized and used as internal standards. The lower limits of quantification (LOQ) obtained were below 150ng/g and limits of detection (LOD) were bellow 100ng/g for all analytes. The method showed good linearity in the range of concentration studied (LOQ-2000ng/g), with coefficient of linearity better than 0.98. The precision assay, given by the relative standard deviation (RSD) of the method was lower than 15% for all FAEEs studied. When the method was applied to real samples, it was possible to detect trace levels of some FAEEs from non-suspected ethanol exposed newborns.