Search results for "Pill"
showing 10 items of 1870 documents
Synchronized gradient elution in capillary liquid chromatography
2013
Abstract The synchronization of injection valve operation and gradient elution in capillary liquid chromatography (cHPLC) is studied. Focus is placed on the cHPLC systems which rely on the splitting of a primary flow to provide the much smaller secondary flow required at the injection device and analytical column. Owing to the tiny secondary flow rates, synchronization is necessary to achieve proper optimization of gradient elution methods. Otherwise, there is a risk of having the analytes totally or partially eluted in the initial isocratic conditions, and there is no control on the actual gradient profile reaching the column. Synchronization is first achieved by switching back the valve t…
On-line Chloride Interference Removal for Arsenic Determination in Waste Water and Urine by ICP-MS Using a Modified Capillary
2002
The determination of arsenic in environmental samples like waste waters from industrial effluents and in biological samples like urine is very important due to the toxic nature of some of its species at moderate levels of exposure. The objective of this study was to evaluate the capability of modified anionic capillaries to remove chloride for ICP-MS determination of arsenic, which causes spectral interference due to formation of 40 Ar 35 Cl + . Also high chloride content gives non-spectral interferences. The results indicate that arsenic at a concentration higher than 1 µg L m 1 in a matrix with a chloride content up to 600 mg L m 1 can be accurately determined using a 3-aminopropyltrimeth…
High-resolution pyrolysis–gas chromatography with a movable reaction zone
1997
Abstract A new device was constructed for pyrolysis–gas chromatography and it was laboratory tested. The device enables the thermal degradation of polymers inside a capillary pre-column and transfer of the reaction zone into a column oven. The pyrolysis procedure described protects the thermally sensitive compounds prior to pyrolysis, prevents the process of irreversible condensation of high-boiling pyrolysis products during the chromatographic process and eliminates extracolumn effects on the peak broadening.
Gas—liquid chromatographic analyses
1984
Abstract The gas choromatographic retention behaviour of veratrole and all nine chlorinated veratroles was studied on SE-30 and OV-351 capillary columns. Temperature programming from 100°C at 6°C min−1 and isothermal operation at 140, 160, 180 and 200°C were used. The complete separation of a mixture was obtained on SE-30, the isomers being eluted in order of their degree of chlorination. On OV-351, however, the 3,4,5-trichloro and tetrachloro isomers overlap with temperature programming, being separated at 140, 160 and 200°C. Retention indices and increments of retention indices for each position of substitution are examined and the effect of increasing temperature on retention is discusse…
Optimization of experimental conditions for the identification of pesticide mixtures on six GLC columns
1994
Gas chromatographic and gas chromatographic-mass spectrometric studies of acetate esters of chlorinated phenols
1983
CAPILLARY ELECTROPHORESIS | Crop-Protecting Agents
2007
Capillary eletrophoresis (CE) is becoming an advantageous technique for determining crop protecting agents as a result of its simplicity and high separation efficiency. Controversely, inappropriate limits of detection (LODs) and a lack of selective detectors restrict its applications. The present article provides a general idea of recent advances in off-column and on-column approaches to trace enrichment in analyzing real samples, and recapitulates the determination of crop-protecting agents by conventional CE as well as by emerging techniques, such as CE-laser induced fluorescence (LIF) or CE-mass spectrometry (MS). The usefulness of these approaches in food and environmental applications …
Analytical Techniques for Furosemide Determination
2006
Abstract Due to the clinical importance of furosemide, a large number of analytical procedures to detect the presence of this drug in pharmaceutical and physiological samples has been developed. In this manuscript, a review of the most frequent analytical techniques described to determine furosemide is presented. Special attention has been paid to spectrophotometric and chromatographic techniques, but also to relevant methods using capillary electrophoresis or flow‐injection analysis, as well as the detection modes coupled to these techniques. The review also focuses on the different degradation pathways of the drug and cautions to prevent it, otherwise rarely or confusedly mentioned in the…