Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 304 for “"Detection limit"”.
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Quantitative analysis of volatile organic compounds (VOCs) in soil via passive sampling : polyethylene sampler design and optimization
… predict VOC soil vapor concentrations is still limited. A polyethylene (PE) quantitative passive sampler using performance reference compounds and deployed via a hand driven probe is proposed as a solution. Additionally, a 1D diffusion mass transfer model was developed in MATLAB to predict the …
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Determination of hydrogen peroxide using immobilized chemiluminescence reagents and flow injection analysis
… peroxide using solution-phase hemin as catalyst (detection limit = 0.4 $\mu$M, relative standard deviation (rsd) = 2.5%). Next, horseradish peroxidase (HRP) was immobilized on nylon membranes. Luminol was immobilized on to an anion exchange resin and packed in a column. When used in the FIA mode, …
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Analytical application of proton-induced prompt photon specrometry
… the yields of about 2200 gamma-rays and their detection limit for analysis. Because the data were measured under identical experimental conditions, the relative values may be generally applicable. For each element, the gamma-ray spectrum and the numerical data are presented in tables listing …
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Time series photometry of the dwarf planet Eris
… that the rotation period of Eris was below the detection limit of the data, so this detection limit was calculated. For a 6 hour period, the data would have had a 2 sigma significance for a full amplitude of 0.16 magnitudes, a 12 hour period is 0.125 magnitudes, an 18 hour period is 0.155 …
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Development of a Magnetically Enhanced Quartz Crystal Microbalance
… to immunosensors has often been driven by, and limited to, the analyte detection limit of the system in use. Recently, a great deal of attention has been paid to piezoelectric sensing devices, more specifically: quartz crystal microbalances (QCM). In an attempt to push the detection limit of …
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CHEMILUMINESCENCE ANALYSIS BASED ON TWO PHASE REACTANT SYSTEMS
… new approach to analysis with chemiluminescent detection is proposed and demonstrated. Two Phase Chemiluminescence utilizes an immobilized reagent bulk phase and a sample phase which contains the analyte. The analyte is permitted to diffuse into the reagent phase under controlled conditions. A …
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Liquid Crystal-Based Biosensors for the Detection of Bile Acids
… diseases. Conventional methods of bile acid detection such as chromatography-mass spectrometry and enzymatic reactions are complex and expensive. It is highly desired to have a simple, fast, and low-cost detection of bile acids that is available for self-testing or point-of-care testing. To …
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Fluorescence Detectors for Proteins and Toxic Heavy Metals
… detector for proteins is described. The detection technique was based on two-photon excitation intrinsic protein fluorescence using a visible 532 nm diode-pumped nano laser as the excitation source. Proteins that exhibit intrinsic fluorescence must contain at least one tryptophan, …
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The Use of Mass Spectrometry for the Analysis of Biological Samples From Macro- and Microorganisms
… to the stainless steel target. An excellent detection limit of 500 fmol was obtained using hydrophobic membranes.
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Flow injection analysis (FIA) determination of lead by hydride generation in banded coral skeletons /
… system were optimized to achieve a good detection limit and sample throughput. The technique developed gave a detection limit of 0.7 ng.ml-l(3ob). The precision at 20 ng.ml"* level was 1.6 % RSD with 1 1 measurements (n=l 1). Volume of sample loop was 500 |J.l. A sample throughput of 120 …
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Development of an optical fibre array fluorosensor for monitoring in the aqueous environment.
… investigated. The technique of fluorescence detection was chosen as the preferred method to be used in the novel Optical Fibre Array Fluorosensor (OFAF) developed during the work. The initial benchtop instrument development and testing of the single probe/array white light system as well as …
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Printable graphene sensing systems for drug and alcohol detection
… of several newly created selective and sensitive detection techniques for drugs and alcohol, involving the use of 2D materials. Thesis discusses the strategies used to turn pristine graphene into a highly selective sensor and how reliable developed sensors are when testing various authentic …
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A System For Conducting Laser-Induced Fluorescence Measurements On Gas Mixtures Exposed To Alpha Radiation
… that can be used to develop an alternative detection method that can be implemented from a safe distance. The selection of molecules for experimental validation has been limited to those which can be detected utilizing cavity ringdown spectroscopy. The current model indicates nitric oxide …
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Designing, construction and analysis of line-scanning detection instrument for photonic crystal enhanced fluorescence
… and analysis of a portable line-scanning detection instrument for photonic crystal enhanced fluorescence. In order to increase the fluorescence signal for low-concentration detection, we introduced the photonic crystal enhanced fluorescence detection modality and demonstrated that it is a …
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Portable EIS and SERS sensing with flexible sensors
… function, 100 cells per milliliter detection limit has been achieved. In the following dissertation, the difficult-to-fabricate silicon sensor was replaced by a filter-based sensor, combining with a 3D printed scaffold and low-melting 3D printed filament confining the microfluidic …
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Microfluidic Techniques for Protein Detection and Manipulation
… interactions, but each class of methods has key limitations. In particular, dissociation constants of biologically relevant interactions are often in the nM to μM range, probing at such low concentrations requires highly sensitive techniques. An improved understanding of the functioning of …
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Sample Preparation/Concentration for Trace Analysis in GC/MS (A study of solid phase microextraction and headspace sampling)
… as potato chips and coffee. The technique gave a detection limit of 2 ppb for Veltol Plus ® which is 200 times more sensitive than conventional GC technique. Headspace injection is characterized by simple and easy handling of complicated solid and solution matrices. Headspace injection, however, …
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In Vitro Selection of Highly Efficient DNA Enzymes as RNA Nucleases and Metal Biosensors
… Pb2+ and the high sensitivity of fluorescence detection, 17E can measure the presence of Pb2+ ions over a concentration range of three orders of magnitude, with a detection limit as low as 10 nM. This system represents the first example of DNA-based biosensor for metal ions. Similar approaches …
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Anharmonic Acoustic Technique for Detection of Surface-bound Particles
Receptor-based biological detection techniques often suffer from the problem of non-specific interactions. This is largely due to the presence of weak electrostatic and Van der Waals forces between the receptor and the non-target substances in the analyte that are not easily dissociated in …
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Efficacy of Ultraviolet Light and Antimicrobials to Reduce Listeria monocytogenes in Chill Brines
… from approximately 6 log CFU/mL to below the detection limit (i.e., 1 log CFU/mL) in 15 minutes with the reduction rate of 0.87 log CFU/mL per minute. However, cells were detectable by enrichment through 120 minutes. The highest rate of decline (0.90 log CFU/mL per minute) was achieved by the …
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