Determination of dehydroepiandrosterone sulfate in plasma by a one-step enzyme immunoassay with a microtitre plate.

1985 ◽  
Vol 31 (11) ◽  
pp. 1876-1879 ◽  
Author(s):  
T K Dhar ◽  
C Müller ◽  
M Schöneshöfer
Keyword(s):  
Hydrogen Peroxide ◽  
Detection Limit ◽  
Enzyme Immunoassay ◽  
Cost Effective ◽  
Dehydroepiandrosterone Sulfate ◽  
Turnaround Time ◽  
Microtitre Plate ◽  
Standard Curve ◽  
One Step

Abstract We have developed a rapid and cost-effective enzyme immunoassay for dehydroepiandrosterone sulfate (DHEA-S) in plasma, performed with samples on a microtitre plate within 2.5 h. No extraction or centrifugation steps are involved. The 3-hemisuccinate of dehydroepiandrosterone is labeled with horseradish peroxidase, then mixed with hydrogen peroxide substrate in the presence of the chromogen, tetramethylbenzidine. The detection limit of the assay is 12.5 pg of DHEA-S per well. Intra- and interassay CVs at three steroid concentrations (12.8, 1.28, and 0.16 mumol/L) ranged from 2.3 to 5.4% and 6.1 to 8.4%, respectively. Results correlated well (r = 0.95) with those of a radioimmunoassay with iodinated DHEA-S. The turnaround time for 41 samples (in duplicate) is 2.5 h, which includes 2 h of incubation time. The sensitivity of this one-step version and the linearity of its standard curve are equivalent to those of a less practicable two-step version. This technique may replace coated-tube enzyme immunoassays for routine use.

Rapid Fluorometric Determination of Benzo(a)pyrene in Foods

1982 ◽  
Vol 45 (2) ◽  
pp. 139-142 ◽  
Author(s):  
YASUHIDE TONOGAI ◽  
SHUNJIRO OGAWA ◽  
MASATAKE TOYODA ◽  
YOSHIO ITO ◽  
MASAHIRO IWAIDA
Keyword(s):  
Detection Limit ◽  
Peak Height ◽  
Excitation Wavelength ◽  
Activated Alumina ◽  
Fluorometric Method ◽  
Fluorometric Determination ◽  
Standard Curve ◽  
Layer Chromatography ◽  
Entire Procedure

A simple and rapid fluorometric method for determining benzo (a) pyrene in foods was developed. Benzo (a) pyrene is extracted from foods with n-hexane:ether mixture (4:1), purified through a column of activated alumina and determined fluorometrically. An excitation wavelength of 295 nm and emission wavelength of 403 nm were used for calculating concentrations of benzo (a) pyrene. The peak height at 403 nm and baseline between 392 and 418 nm were employed to derive a standard curve for quantitating benzo (a) pyrene. A calibration curve for between 0.04 – 4 ng/ml of benzo (a) pyrene was used. Recoveries of benzo (a) pyrene from 14 kinds of food spiked at levels of 20 and 2ppb were within the range of 79.5 – 93.8% and 50.0 – 80.6%, respectively. The entire procedure takes only one hour with the detection limit being 0.1 ppb. Benzo (a) pyrene detected was reconfirmed by thin-layer chromatography.

Sandwich enzyme immunoassay of Mucor miehei proteinase (Fromase) in cheese

1989 ◽  
Vol 56 (5) ◽  
pp. 793-797 ◽  
Author(s):  
Pavel Rauch ◽  
Igor Hochel ◽  
Eva Beránková ◽  
Jan Káš
Keyword(s):  
Detection Limit ◽  
Horseradish Peroxidase ◽  
Enzyme Immunoassay ◽  
Commercial Preparation ◽  
Mucor Miehei ◽  
Cross Reactions ◽  
Sandwich Enzyme Immunoassay

SummarySandwich enzyme immunoassay of Mucor miehei proteinase (from the commercial preparation Fromase) has been developed using horseradish peroxidase as a marker. The enzyme may be determined to a detection limit of 50 ng/ml. Slight cross reactions by chymosin, bovine, porcine and chicken pepsin did not affect the assay. Recovery of Fromase added to cheese extracts varied between 92 and 106%. The method was used for the determination of M. miehei proteinase in different cheese extracts.

scholarly journals Development of enzyme immunoassay for endogenous ouabain-like compound in human plasma

1997 ◽  
Vol 43 (5) ◽  
pp. 715-722 ◽  
Author(s):  
Steven Harwood ◽  
John A Little ◽  
Gerard Gallacher ◽  
David Perrett ◽  
Raymond Edwards ◽  
...  
Keyword(s):  
Detection Limit ◽  
Healthy Volunteers ◽  
Enzyme Immunoassay ◽  
Human Plasma ◽  
Hplc Analysis ◽  
Cross Reactivity ◽  
Standard Curve ◽  
Endogenous Ouabain ◽  
Endogenous Steroid ◽  
Hplc Study

Abstract Widespread evidence supports the existence of an endogenous digitalis-like compound in mammals. We report here the development of a novel enzyme immunoassay for ouabain that, in conjunction with a detailed HPLC study, identifies a ouabain-like compound (OLC) in extracted human plasma. The assay is sensitive—minimum detection limit for OLC 37 pmol/L (11 pmol/L in plasma)—and has a working range (between-assay CV <10%) of 180–10 000 pmol/L (54–3000 pmol/L in plasma). Mean recoveries of ouabain added to plasma ranged from 90% to 100%, and plasma extracts diluted in parallel to the standard curve. Plasma OLC concentrations in 10 healthy volunteers averaged 92 pmol/L (range 55–168), assuming 100% cross-reactivity of OLC in the ouabain assay. HPLC analysis with two distinct chromatographic conditions demonstrated that endogenous human plasma OLC co-eluted with authentic ouabain. The enzyme immunoassay is rapid and easy to perform and will support further investigation of the nature of this controversial endogenous steroid.

Rapid determination of the hypoxanthine increase in ischemic exercise tests.

1988 ◽  
Vol 34 (8) ◽  
pp. 1607-1610 ◽  
Author(s):  
P A Bolhuis ◽  
R Zwart ◽  
P R Bär ◽  
M de Visser ◽  
H J van der Helm
Keyword(s):  
Hydrogen Peroxide ◽  
Detection Limit ◽  
Rapid Determination ◽  
Serum Lactate ◽  
Benzenesulfonic Acid ◽  
Exercise Tests ◽  
Ph Optimum ◽  
Absorbance Maximum ◽  
Myoadenylate Deaminase

Abstract After ischemic exercise tests, performed to detect glycogenoses or myoadenylate deaminase (EC 3.5.4.6) deficiency, the increases in serum lactate and ammonia usually are measured. Determination of hypoxanthine instead of ammonia can also be used to show myoadenylate deaminase deficiency, but HPLC of hypoxanthine is time-consuming. As a substitute, we developed an indirect enzymatic equilibrium method for hypoxanthine based on coupling the chromogenic system 3,5-dichloro-2-hydroxy-benzenesulfonic acid/4-aminophenazone with formation of hydrogen peroxide by xanthine oxidase (EC 1.1.3.22). The pH optimum is at 7.8 and the absorbance maximum at 510 nm. The calibration curve is linear from 0 to 100 mumol/L and the detection limit is 0.9 mumol/L. Analytical variability (CV) was 1.5% to 3.6% within-run, 4.5% to 8.5% between-run. The assay can be performed with a standard spectrophotometer or a centrifugal analyzer. The coefficient of correlation was 0.68 between hypoxanthine and ammonia increases in plasma from controls who performed the exercise test.

Enzyme immunoassay of insulin at picomolar levels based on the coulometric determination of hydrogen peroxide

2008 ◽  
Vol 135 (1) ◽  
pp. 304-308 ◽  
Author(s):  
Fumio Mizutani ◽  
Eiji Ohta ◽  
Yasuhiro Mie ◽  
Osamu Niwa ◽  
Tomoyuki Yasukawa
Keyword(s):  
Hydrogen Peroxide ◽  
Enzyme Immunoassay ◽  
Coulometric Determination

Development of a Highly Sensitive Chemiluminescence Enzyme Immunoassay for the Determination of Bisphenol A

2013 ◽  
Vol 726-731 ◽  
pp. 1283-1286
Author(s):  
Li Rui Liu ◽  
Li Qin Liu ◽  
Xue Qing Chen ◽  
Guo Qing Shi
Keyword(s):  
Detection Limit ◽  
Bisphenol A ◽  
Enzyme Immunoassay ◽  
Rapid Determination ◽  
Secondary Antibody ◽  
Average Recovery ◽  
Highly Sensitive ◽  
Optimized Conditions ◽  
Chemiluminescence Enzyme Immunoassay

A highly sensitive chemiluminescence enzyme immunoassay (CLEIA) method for the determination of bisphenol A (BPA) was developed, which used a secondary antibody labeled with horseradish peroxidase detected with a luminol-based substrate. Under the optimized conditions, the linear range was 0.01μg/mL~0.74μg/mL, and the detection limit was 0.008μg/mL. The average recovery for BPA in barreled water was 104%. This developed method could be applied for the selective, high-throughput, and rapid determination of BPA in barreled water.

scholarly journals Photoinduced triplet-state electron transfer of platinum porphyrin: a one-step direct method for sensing iodide with an unprecedented detection limit

2015 ◽  
Vol 3 (13) ◽  
pp. 6733-6738 ◽  
Author(s):  
Dilshad Masih ◽  
Shawkat M. Aly ◽  
Erkki Alarousu ◽  
Omar F. Mohammed
Keyword(s):  
Electron Transfer ◽  
Detection Limit ◽  
Triplet State ◽  
Direct Method ◽  
Economical Method ◽  
State Electron ◽  
One Step ◽  
Platinum Porphyrin ◽  
First Time

Herein, we report for the first time the photoinduced triplet-state electron transfer of Pt(ii)TMPyP as an easy, rapid, environmentally friendly, ultra-sensitive and economical method for the determination of iodide in the aqueous phase.

Comparison of EEIM and Cumulative Efficiency Methods for the Evaluation and Optimization of Advanced Oxidation Processes for DOC Removal from Water

2003 ◽  
Vol 6 (2) ◽  
Author(s):  
Gary R. Peyton ◽  
Michael J. Fleck ◽  
Mary Hagen LeFaivre
Keyword(s):  
Hydrogen Peroxide ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Cost Effective ◽  
Electrical Energy ◽  
Process Selection ◽  
Oxidation Processes ◽  
Tandem Process ◽  
Using Data

AbstractTwo published criteria for analyzing and optimizing Advanced Oxidation Processes are compared with respect to their usefulness for process optimization and for determination of the most cost-effective of several candidate processes for a particular application. The Cumulative Efficiency (CE) method compares the amount of target contaminant removed per amount of oxidant used. The Electrical Energy per Mass (EE/M) method compares electrical energy required per kilogram of target pollutant removed. The methods were evaluated using data from treatability studies for DOC removal from a ground water contaminated with 50 mg/L of organic carbon, using processes consisting of combinations of ozone, hydrogen peroxide, and ultraviolet light. It was found that the CE method gave better information about how to manipulate the chemistry for optimization, while the EE/M method provided clearer guidance for process selection on economic grounds, making the methods complimentary in treatability studies. The CE method also predicted that a tandem process might function more efficiently than either of the component single processes, which was found experimentally to be the case.

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