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Development of an assay for the detection of cytomegalovirus in urineAllen, Robert Douglas, III 12 1900 (has links)
No description available.
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Speciation and identification of low molecular weight organoselenium metabolites in human urineHoang, Tiffany Truc 05 1900 (has links)
No description available.
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Steroid estrogen conjugates in the urine of laying hens : a thesis.Baker, Susan Jane January 1977 (has links)
No description available.
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Steroid estrogen conjugates in the urine of laying hens : a thesis.Baker, Susan Jane January 1977 (has links)
No description available.
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Confirmation of urinary benzodiazepines by gas chromatography/mass spectrometryWest, Robert E., 1952- January 1989 (has links)
A new method is described for the quantitative analysis of urinary benzodiazepines by gas chromatography/mass spectrometry. Development work was aimed at satisfying federal requirements for methods used in forensic urine drug testing which have become the standard in the laboratory industry. Trimethylsilyl (TMS), tert-butyl-dimethylsilyl (TBDMS) and benzophenone derivatives were tested in the development of the new assay. TBDMS derivatives were found to be the most suitable for the analysis of six common benzodiazepine metabolites. Precision for all metabolites tested, as measured by the within run coefficient of variation, was less than 7% at 100 ng/ml (n = 15). Assay sensitivity varied with the specific analyte in the range of 5 to 10 ng/ml. Validation of the procedure included the reanalysis of benzodiazepine positive urine specimens obtained from a forensic drug testing laboratory and comparison of the results from the independent assays. These specimens were tested first by radioimmunoassay using a 100 ng/ml cutoff and then confirmed by GC/MS. Sensitivity was sufficient to confirm the presence of benzodiazepine metabolites in all specimens tested.
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Studies on the urinary conversion products of orally administered isoflavones in the domestic fowl.Tang, Gregory Wing Chan. January 1968 (has links)
No description available.
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Studies on the urinary conversion products of orally administered isoflavones in the domestic fowl.Tang, Gregory Wing Chan. January 1968 (has links)
No description available.
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An evaluation of analytical procedures for detection of drug abuse with particular reference to opiatesLow, Ann Stewart January 1998 (has links)
No description available.
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Liquid phase microextraction of hallucinogenic compounds from human urine samples based on single hollow fibre followed by chromatographic determinationNcube, Somandla January 2016 (has links)
A dissertation submitted to the Faculty of Science, University of the
Witwatersrand in fulfilment of the requirements for the degree of
Master of Science. University of the Witwatersrand, Johannesburg, March 2016 / A liquid phase microextraction based on single hollow fibre followed by liquid
chromatographic determination was developed for the extraction and
quantification of the hallucinogenic muscimol and its two precursors, tryptophan
and tryptamine from urine samples. A multivariate design of experiment was used
in which a half fractional factorial approach was applied to screen six potential
factors (donor phase pH, acceptor phase concentration, supported liquid
membrane composition, stirring rate, extraction time and salt content) for their
extent of vitality on the extraction of muscimol, tryptophan and tryptamine using
the developed method. Four factors were identified as essential for an enhanced
enrichment of each of the three research analytes from diluted urine samples.
The paired vital factors were then optimized using central composite designs
where empirical quadratic response models were used to visualize the response
surface through contour plots, surface plots and optimization plots of response
output. When the muscimol-based optimum factor levels were applied for the
simultaneous extraction of the three research analytes, a composite desirability of
0.687 was obtained implying that the set conditions were ideal for a combined
extraction of the analytes from the donor phase into the acceptor phase across a
supported liquid membrane impregnated with a carrier molecule. This was an
acceptable result considering that only the optimized muscimol factor levels were
set as universal factor values. Muscimol was the analyte of interest in this
research.
The composite desirability value was predicted by setting the extraction
conditions to 20% (w/w) di-(2-ethylhexyl) phosphoric acid (DEHPA) in dihexyl
ether (DHE) supported on the walls of a hollow fibre into a 200 mM HCl acceptor
phase inside the hollow fibre from a 20% (v/v) diluted urine donor phase spiked in
the 0.1 – 10 μg mL-1 analyte concentration range maintained at pH 4 and stirred at
800 rpm for 60 mins. Experimentally, average enrichments of 4.1, 19.7 and 24.1
were obtained for muscimol, tryptophan and tryptamine, respectively.
iv
The complexity of urine and the anionic nature of the carrier molecule embedded
on the supported liquid membrane resulted in interfering peaks that could not be
completely resolved from the analyte peaks. Thus matrix-based calibration curves
were used to address matrix effects.
Various statistical approaches were used to validate suitability of the developed
method for its potential use in quantifying muscimol and its precursors from urine
samples. These validation measures were used as a way of determining the
method’s ability to maintain the extraction process at equilibrium over a specific
range of analyte concentrations over a period of analyte existence in a urine
sample. The r² values of the matrix-based linear regression prediction models
ranged from 0.9933 to 0.9986. The linearity of the regression line of the matrixbased
calibration for each analyte was directly linked to the analyte enrichment
repeatability. Simultaneous analyte enrichment repeatability over a 0.1 – 10 μg
mL-1 analyte spiking concentration ranged from an RSD value of 8.3% to 13.1%.
Limits of detection were 0.021 μg mLˉ¹, 0.061 μg mL-1 and 0.005 μg mL-1 for
muscimol, tryptophan and tryptamine, respectively.
Other validation parameters that were considered included specificity (and
selectivity), accuracy, robustness, extraction range and system suitability. The
accuracy of the developed method was reported as the reproducibility of
enrichment factor values over six spiking concentrations used in constructing
matrix-based calibration curves. System suitability was limited to an HPLC-UV
approach. Method suitability was addressed through a comparative summary in
which the LOD, LOQ and r² values for the developed method were compared to
other methods that have been used to extract muscimol from urine samples. The
relevance or acceptability of the enrichment factor values obtained for the
extraction of the three analytes was achieved by comparison with enrichment
factor values of several compounds with similar polarity that have been extracted
from urine samples using carrier-mediated hollow fibre liquid phase
microextraction. / GR2016
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CystinuriaCleland, Joan Burton. January 1947 (has links) (PDF)
Typewritten copy Includes bibliographical references.
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