Analysis of bromacil, diuron and 3,4-dichloroaniline in contaminated well water, using a high-performance liquid chromatographic column-switching procedure

Goewie, C.E.; Hogendoorn, E.A.

doi:10.1016/s0021-9673(00)90051-7

Cited by 39 publications

(13 citation statements)

References 6 publications

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“…The results were analysed statistically using the linear regression analysis of the one set of assay results versus the other. 22,23…”

Section: Comparison Studiesmentioning

confidence: 99%

“…The next stage was to find two compatible eluents of different elutropic strengths. 23 One should have a poor elution capability to concentrate the analytes on the pre-column and the second a strongly eluting solvent to elute the analytes off the pre-column and onto the analytical column. The washing eluent should also be miscible with the mobile phase, as even slight incompatibility could result in a plug of solvent travelling down the analytical column partially carrying sample components which may cause band broadening.…”

Section: Optimisation Of Analyte Separation In Human Plasmamentioning

confidence: 99%

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Bioavailability studies of oral dosage forms containing levodopa and carbidopa using column-switching chromatography followed by electrochemical detection

Sagar

Smyth

2000

Analyst

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A reliable multi-dimensional column chromatographic method employing amperometric detection using a carbon fibre microelectrode procedure was used for monitoring the plasma profiles and to evaluate the pharmacokinetics and bioavailability of levodopa (L-dopa) and carbidopa (C-dopa), after ingestion of oral formulations containing these drugs. The peak currents obtained for the different analytes were directly proportional to the analyte over the concentration range 0.02-4 micrograms ml-1. Using this method, the minimum detectable concentration was estimated to be 5 and 8 ng ml-1 for L-dopa and C-dopa, respectively. Recovery studies ranged from 93.83 to 89.76%, with a relative standard deviation of less than 7%. The study was carried out in two separate weeks on five healthy non-patient fasted male/female volunteers in the age range 20-37 years and weighing between 60 kg and 78 kg. The pharmacokinetic profile of two controlled-release products containing both L-dopa and C-dopa (Sinemet CR3 and CR4) was compared on the one hand and Sinemet conventional tablets on the other. The pharmacokinetic parameters, peak concentration (Cmax), the time taken to obtain this level (Tmax), elimination half-time T1/2, elimination rate constant (Kel), plasma level ratio, fluctuation index (FI) and the area under the time-concentration curve (AUC0-8), were investigated for each individual formulation. A comparison of the uptake of L-dopa from the conventional formulation showed that L-dopa entered the plasma and achieved peak levels higher than that of the controlled release formulations. However, it showed a much higher fluctuation index and the plasma concentrations were more stable with the controlled release formulations. The data also indicated a very low accumulation of both levodopa and carbidopa following repeated administration of the drugs, which was consistent with their relatively short half-lives (less than 2 h). In contrast, the half-life for the metabolite 3-orthomethyl dopa (3-OMD) is in the order of 13 h. As a result, there was an extensive accumulation of 3-OMD and its levels were significantly higher than those of levodopa or carbidopa upon repeated administration. Urine recoveries of the three analytes over one 8 h dosing interval showed that the majority of the excreted levodopa and carbidopa was recovered during the first 4 h, and there is proportionally greater excretion of the carbidopa dose than the levodopa dose.

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“…The results were analysed statistically using the linear regression analysis of the one set of assay results versus the other. 22,23…”

Section: Comparison Studiesmentioning

confidence: 99%

Section: Optimisation Of Analyte Separation In Human Plasmamentioning

confidence: 99%

Bioavailability studies of oral dosage forms containing levodopa and carbidopa using column-switching chromatography followed by electrochemical detection

Sagar

Smyth

2000

Analyst

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“…Table 5 reports the estimated breakthrough volumes obtained with the 1 x 0.21 cm ID precolumns packed with C18 silica and PRP-1, respectively. The copolymer-based C18 and (b) a PRP-I precolumn on percolated sample volume Solute Recovery (7;) for sample volume ( m l ) 10 25 …”

Section: Amounts Preconcentrated and Recoveries On Each Precolumnmentioning

confidence: 99%

Off-Line and On-Line Preconcentration Techniques for the Determination of Phenylureas in Freshwaters

Hennion

Subra

Rosset

et al. 1990

International Journal of Environmental Analytical Chemistry

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“…A number of instrumental methods have been developed for the detection of bromacil in soil and water samples (14, [16][17][18][19][20] . These analyses share drawbacks such as the need of laborious extraction and/or cleanup procedures, highly qualified analysts, and expensive instrumentation.…”

Section: Assay For Bromacilmentioning

confidence: 99%

Near-Infrared Fluorescent Immunoassays: A Novel Approach to Environmental Analysis

Swamy

Danesvar

Evans

et al. 1997

ACS Symposium Series

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The near-infrared (NIR) region of spectrum provides many advantages over conventional UV--visible region and is particularly useful when background interference is the primary concern. Many NIR fluorophores have high molar absorptivities and fluorescence quantum yields. The use of laser diodes for excitation and photodiodes for detection makes the NIR fluorophores an ideal choice as tracers for various applications. NIR fluorescence immunoassays (NIRFIAs) for disease-related antigens have been developed and optimized in our laboratory during the past few years. NIRFIA can be used in both sandwich and competitive formats. We have successfully adapted the NIRFIA as both a microtiter plate assay and a fiber optic probe. This paper is focussed on the environmental analytical applications of this novel technique. Physical properties of ideal NIR labels and engineering problems of devising remote sensors are discussed. Conventionalimmunoassays have been recognized as a powerful tool in the analysis of minor components in a complex media.The use of laser induced fluorescence in the development of immunoassays has been reviewed (1). The limitations in using conventional lasers as an excitation source are size, high price, and maintenance costs. Recent advances in semiconductor laser technology have made the use of these lasers as an excitation source more

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Analysis of bromacil, diuron and 3,4-dichloroaniline in contaminated well water, using a high-performance liquid chromatographic column-switching procedure

Cited by 39 publications

References 6 publications

Bioavailability studies of oral dosage forms containing levodopa and carbidopa using column-switching chromatography followed by electrochemical detection

Bioavailability studies of oral dosage forms containing levodopa and carbidopa using column-switching chromatography followed by electrochemical detection

Off-Line and On-Line Preconcentration Techniques for the Determination of Phenylureas in Freshwaters

Near-Infrared Fluorescent Immunoassays: A Novel Approach to Environmental Analysis

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