chromatographic determination of carbamate pesticides in environmental samples

... Preconcentration of aminoalcohols in urine by combined use of offcolumn static three-phase LPME and on-column stacking for trace analysis by CZE ………………………………………………………………………….114 4.3.1.1 Determination of aminoalcohols ... analysis of aromatic amines in water samples [89], phenoxy herbicides in bovine milk [90] and aminoalcohols in urine [91] Recently dynamic three-phase LPME was developed to determine anilines combined ... Mental Health Services Administration established cut-off values for preliminary testing Cocaine and cocaine metabolites in urine samples have also been investigated using LPME [58] 16 Recently,...

Ngày tải lên: 17/09/2015, 17:20

... used to investigate the chemical degradation behavior of N-methylcarbamate in environmental water samples Propoxur was selected as a model compound to study the degradation behavior in ultrapure ... ultrapure water, drinking water, rain water, river water and seawater under various pH and irradiation sources (sunlight, darkness, indoor incandescent lighting and artificial UV lighting) Hydrolysis ... pH-dependent irrespective of the type of water matrix Light intensity could prompt degradation significantly under mild alkaline conditions, while its influence was minor at higher pH (pH > 9)...

Ngày tải lên: 16/09/2015, 17:13

... power setting for the microwave heating This setting was proportional to the number of samples undergoing extraction during one run Furthermore, according to previous experience with MAE and intuition, ... within 1-2 minutes of microwave heating during the extraction An important point to note when employing the OAD procedure is that although some parameters (duration of extraction and volume of ... follows: 20-ml of methanol, an optimum microwave heating temperature of 80 °C, and a 6-min of microwave heating Table 5-4 Variance analysis table in the OA (27) matrix for the optimization of MAE from...

Ngày tải lên: 16/09/2015, 17:13

... increased to 200°C at a rate of 25°C/min, then maintained at 200°C for min; a second ramp 230°C at rate of 5°C/min, increased to 280°C at a rate of 20°C/min; The final temperature of 280°C was held for ... methanol 88 An interesting result observed from Fig 4-6 is that in the same solvent, the recovery increases in going from PAHs to PCBs, and then to triazines (i.e, increasing polarity of analyte) ... degradation of each carbamate in different extractants under MAE conditions was determined in the absence of soil From Fig 4-3, it can be seen that thermal degradation of all five carbamates occurred in...

Ngày tải lên: 16/09/2015, 17:13

... application of LC-APCI-MS for the determination of carbamates: carbofuran and 3hydroxy-carbofuran, and the analysis of triazine herbicides in water [8] LC-ESI-MS has been ... simultaneous determination of carbamate pesticides [7, 9-12] In addition, with the introduction of ion-trap mass analyzers (ITMS), higher sensitivity and accuracy of the structural information ... degradation rates increase in the order of increasing pH (seawater [pH 7.8] or river water [pH 7.6] > drinking water [pH 7.03] > rain water [pH 4.2]) For example, the percentage of degradation in seawater...

Ngày tải lên: 16/09/2015, 17:13

... 60mesh sieve In order to remove possible traces of PAHs, PCBs, triazines, carbamates and other organic contaminants, 100 g of each of the soil sample was immersed in 200 ml 46 each of methanol, ... Polychlorinated biphenyls (PCB-1242 and PCB-1248) were purchased as individual standard stock solutions containing a nominal concentration of 100 µg/ml in methanol from Ultra-Scientific Atrazine (purity ... possible trace organic contaminants prior to preparation, all of them were washed in fresh running water and then rinsed with deionized water The fish samples were grinded in a mortar and pestle with...

Ngày tải lên: 16/09/2015, 17:13

... separation and determination of pesticide 13 residues in environmental and biological samples In order to obtain qualitative and quantitative information on the presence of trace levels of pesticides ... analysis of triazine and phenylurea pesticides in environmental samples [118]; sample volumes of 20 ml of ground water provided LODs 26 Table 1-5 The application of LC-API-MS for pesticides in environmental ... Table 1-3 Comparison of the boiling points of solvents in open and closed systems [64] Solvent Dichloromethane Boiling point (°C) in open system 39.8* Boiling point (°C) in closed system (175psi)...

Ngày tải lên: 16/09/2015, 17:13

... result of the amino group of one amino acid reacting with the carboxyl group of a second amino acid to form an amide bond (Figure 1.5) Amino acid polymers can be composed of any number of amino ... compared Miniaturization is playing an increasing role in the development of CE It may change the pattern of conventional CE and bring about a new appreciation of simple and low-cost technique As introduced ... possibilities of applying hydrophobic compounds as terminating ions Since the miniaturization has received considerable attention in the recent development of CE The use of microfabrication techniques...

Ngày tải lên: 11/09/2015, 14:27

Ngày tải lên: 17/02/2014, 20:20

... future of parsing in the analysis of dictionary definitions or of any other large text corpus lies in a simpler, less computationally intensive parsing technique In addition, a parser for definition ... most of the duplicate relational triples Finding relational triples by text processing As the performance statistics above show, parsing is painfully slow For the simple business of finding and ... }? warning } of danger (29) noun: Parsing, again Simple text processing, even without such lexical knowledge as parts of speech, is about as accurate as parsing in terms of correct vs incorrect...

Ngày tải lên: 08/03/2014, 18:20

... paradoxical result can be explained in the following way The chance of finding a seed-match and of producing a local alignment of significant similarity rises with the length of the fragment Longer fragments, ... Additional file 1) Therefore, requiring a minimum distance in bitscore between the best and second best hit is Page of 15 very effective in removing most of the remaining reads that would otherwise ... length of the shorter read including the 454 adapter sequence A read is added to an existing cluster if the same condition is met by any one of the sequences in the cluster (single-linkage clustering)...

Ngày tải lên: 09/08/2014, 20:22

... present integral inequalities Main results In the rest of the paper we denote the set of real numbers as R, and R+ = [0, ∞) is a subset of R Dom(f) and Im(f) denote the definition domain and the ... differential equation, while in the second example, we will obtain the bound of the solutions of an integral equation For the sake of proving the global existence of solutions of differential equations, ... R+, R+), and a, j, ψ, ω, a, b, J, Y are defined as in Theorem 2.3 If u Î C(R+ × R+, R+) satisfies the following integral inequality containing multiple integrals β(y) φ(u(x, y)) ≤a(x, y) + [f (s,...

Ngày tải lên: 21/06/2014, 01:20

... action, responding to the arguments of the opponents and foreseeing opposing dangers 33 Secondly, in quoting the declarations of independence of America in 1776 and the declaration of the French ... fell into the tense situation: In the North of Vietnam, the Japanese was about to come in; in the South, the French colonists, hiding behind the British troops, had an intention of occupying the ... discourse analysis involves the study of language in use A wide range of linguistic texts are explored in the study of discourse These might be in either spoken or written form, including a conversation...

Ngày tải lên: 14/12/2013, 00:41

... percentage of errors increase In terms of error causes, the following findings have been obtained: - Most of errors collected belong to intralingual category and there are three main causes which ... major findings above, some following suggestions are made to improve the quality of teaching and learning SVA in English writing at high shool 3.2.1 Suggestion for teaching SVA in English writing ... examples of attraction arise with singular nouns of kind and quantity E.g: a A large number of people are gathering in the square b The majority of them are American c Lots of wood is going to...

Ngày tải lên: 18/12/2013, 10:04

... of surroundings (Nguyen Hoa, 2000: 104) - The indefinite article "a/ an" This indefinite article is capable of being used to signal something that is new owing to its basic meaning of "indefiniteness" ... Subject) of what he will speak about later in Rheme In other words, Theme is the starting point of the utterance or point of departure of the message In many cases (Unmarked), the Theme of a Declarative ... study, secondly explaining the data source, thirdly suggesting some principles of the analysis, and finally describing the procedure of studying 2.2 Research Hypothesis In the investigation, we...

Ngày tải lên: 22/12/2013, 12:59

... successful metabolic engineering of freezing tolerance in plants should include such an analysis of the dynamics of metabolism to gain comprehensive information about the effects of individual overexpression ... that of vInv, the activities of nInv and eInv were low, and became noticeably higher only in Rsch after days of cold exposure (Fig 3B,C) However, in both accessions, values of Vmax for eInv increased ... kept in mind that the sink export rate in our model is composed of assimilate export to sink organs and flux into further pools of carbon-containing metabolites and structural components, e.g amino...

Ngày tải lên: 14/02/2014, 22:20

... phthalates were detected predominantly in indoor air samples. 93) The dominant path of phthalates intake was the ingestion of foodstuffs compared to inhalation of indoor air by children.94) n-Tetradecane ... can meet local needs in dealing with SHS.152) CONCLUSION Healthy indoor air is a fundamental right for people studying in schools, working in of ces and living in residences Indoor air quality ... combustion gases in residences and buildings CO is well-known to cause poisoning by CO-hemoglobin (Hb) formation, inhibiting oxygen utilization by internal organs NO2 sources in buildings include gas...

Ngày tải lên: 17/02/2014, 22:20

... provide important information in terms of optimizing processes of environmental sampling To overcome some of the above-mentioned limitations, an evaluation procedure was designed in a previous study ... subjects interviewed Exploring the generality of such a categorization in other geographical scenes, incorporating the analysis of places considered ‘‘unattractive,’’ is one of the aims of the ... guiding the design of this study is establishing categories of urban places from the perspective of their daily observers, as well as attempting to identify some of the important dimensions of...

Ngày tải lên: 19/02/2014, 17:20

... analysis of environmental work in the sector, including legislation and environmental regulations • Other relevant information on the institutional situation • An analysis of the combined effects of ... unpublished) 20 6.6 Inland shrimp farming The establishment of low salinity shrimp farms in areas far inland from the coast has greatly contributed to maintaining the high production of shrimp in Thailand ... according to Tookwinas (pers comm., 2001) Intensive shrimp farming has introduced a wide variety of side industries at different stages of the shrimp production: feed and chemical manufacturing industries,...

Ngày tải lên: 26/02/2014, 20:20