Evaluation of atrazine soil extraction methods for the determination by enzyme immunoassay and gas chromatography

1994 ◽  
Vol 27 (3) ◽  
pp. 375-383 ◽  
Author(s):  
P. L. Del Valle ◽  
J. O. Nelson
Keyword(s):  
Gas Chromatography ◽  
Enzyme Immunoassay ◽  
Extraction Methods ◽  
Soil Extraction

Substrate-labeled fluorescent immunoassay for phenytoin in human serum.

1979 ◽  
Vol 25 (5) ◽  
pp. 686-691 ◽  
Author(s):  
R C Wong ◽  
J F Burd ◽  
R J Carrico ◽  
R T Buckler ◽  
J Thoma ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Human Serum ◽  
Enzyme Immunoassay ◽  
Serum Sample ◽  
Competitive Binding ◽  
Major Metabolite ◽  
Enzyme Substrate ◽  
Beta Galactosidase ◽  
Assay Conditions ◽  
Substrate Addition

Abstract A homogeneous substrate-labeled fluorescent immunoassay has been applied to the measurement of phenytoin concentrations in human serum. We coupled a fluorogenic enzyme substrate, galactosyl-umbelliferone, covalently to a derivative of phenytoin. Under assay conditions, this drug-substrate conjugate was nonfluorescent but became fluorescent upon hydrolysis catalyzed by bacterial beta-galactosidase. When antibody to phenytoin is bound to the drug-substrate conjugate, it is inactive as an enzyme substrate. Addition of phenytoin to competitive-binding reactions relieves the inactivation, and the resulting fluorescence is proportional to the phenytoin concentration. We validated the fluorescent immunoassay by comparing values for phenytoin obtained with this technique to those obtained by gas chromatography and by enzyme immunoassay (EMIT). All three methods correlated well. The major metabolite of phenytoin, 5-(p-hydroxyphenyl)-5-phenylhydantoin, and other drugs at concentrations expected in serum had no effect on the assay. The fluorescent immunoassay is rapid and simple to perform and requires only 2 microL of serum sample per test.

scholarly journals Evaluation of Biochar Nitrate Extraction Methods

2019 ◽  
Vol 9 (17) ◽  
pp. 3514 ◽  
Author(s):  
Jenna Walsh ◽  
Joseph Sanford ◽  
Rebecca Larson
Keyword(s):  
Extraction Method ◽  
Extraction Efficiency ◽  
Agricultural Soils ◽  
Extraction Methods ◽  
Multiple Methods ◽  
Soil Extraction ◽  
Future Studies ◽  
Different Types ◽  
Increasing Temperature ◽  
Biochar Amendment

Biochar amendment to soil is a method used to mitigate losses of nitrogen leaching through agricultural soils. Multiple methods for extraction of nitrogen have been used, and recent studies have indicated that traditional soil extraction methods underestimate biochar nitrate. This study evaluated the nitrate extraction efficiency of a KCl extraction method under different temperature (20 and 50 °C) and duration (24 and 96 h) conditions. Increasing the duration of extraction from 24 to 96 h did not have a significant impact on extraction efficiency. However, increasing temperature resulted in nitrate extraction efficiencies above 90%. Rinsing the biochar once with deionized (DI) water following filtration after extraction increased the extraction efficiency significantly, but any subsequent rinses were not significant. This study recommends extracting nitrate from biochar using 2 M KCl at 50 °C for a period of 24 h with one additional rinse to increase nitrate recovery above 90%. However, future studies should evaluate this procedure for different types of biochar produced from alternative biomasses and at varying temperatures.

Adaptation of "EMIT" technique for serum phenobarbital and diphenylhydantoin assays to the miniature centrifugal analyzer.

1976 ◽  
Vol 22 (6) ◽  
pp. 905-907 ◽  
Author(s):  
S D Brunk ◽  
T P Hadjiioannou ◽  
S I Hadjiioannou ◽  
H V Malmstadt
Keyword(s):  
Gas Chromatography ◽  
Enzyme Immunoassay ◽  
Reaction Rates ◽  
Anticonvulsant Drugs ◽  
Rate Measurement ◽  
Serum Samples ◽  
Analytical Recovery ◽  
Reagent Cost ◽  
Measurement Mode ◽  
Multiple Samples

Abstract We used a miniature centrifugal analyzer in a spectrophotometric rate-measurement mode to determine the anticonvulsant drugs phenobarbital and diphenylhydantoin in serum, by use of a modified enzyme immunoassay ("EMIT", Syva Corp.) We decreased reagent cost per determination by at least sixfold by means of microscale techniques. Also, the analysis rate is increased by measuring multiple samples simultaneously. Our method requires only 3 mul of serum for duplicate determinations. Replicate analyses of sera containing phenobarbital and diphenylhydantoin gave reaction rates with a CV of 1.5%. Run-to-run CV was 15%. Analytical recovery for drug-supplemented serum samples was 98%, and results for a series of samples compared well with results obtained by gas chromatography (for phenobarbital, r = 0.95; for diphenylhydantoin, r = 0.91).

Comparison of Different Extraction Methods Applied to Volatile Compounds in Wine Samples Previous to the Determination by Gas Chromatography

2004 ◽  
Vol 37 (14) ◽  
pp. 3063-3084 ◽  
Author(s):  
S. Cabredo‐Pinillos ◽  
T. Cedrón‐Fernández ◽  
C. Sáenz‐Barrio
Keyword(s):  
Gas Chromatography ◽  
Volatile Compounds ◽  
Extraction Methods
Sign in / Sign up

Export Citation Format

Share Document