FLUORIMETRIC DETERMINATION OF ADRENAL CORTICOSTEROIDS: OBSERVATIONS ON INTERFERING FLUOROGENS IN HUMAN PLASMA

1964 ◽  
Vol 30 (2) ◽  
pp. 255-263 ◽  
Author(s):  
J. R. DALY ◽  
J. SPENCER-PEET
Keyword(s):  
Experimental Data ◽  
Human Plasma ◽  
Plasma Volume ◽  
Fluorescence Intensity ◽  
Plasma Sample ◽  
Accurate Estimation ◽  
Fluorimetric Determination ◽  
Low Concentrations ◽  
Theoretical Considerations

SUMMARY Simple fluorimetric methods for the determination of corticosteroids are not sufficiently specific to allow the accurate estimation of low concentrations in plasma. It has been noted previously and is confirmed here, that the measured fluorescence is not proportional to the volume of plasma used, but includes a component which is relatively independent of the plasma volume extracted. This gives rise to a positive intercept on the fluorescence axis when fluorescence intensity is plotted against volume. The suggestion that the determination of plasma corticosteroids can be made specific by subtracting the value of this intercept from the measured fluorescence intensity of the plasma sample has been examined. In the light of experimental data and certain theoretical considerations presented here, this suggestion is rejected. It is concluded that the inaccuracy due to interfering fluorogens can be reduced by taking fluorimeter readings within 5 min. of extraction into the fluorescence reagent, but that even then specificity is not complete.

High-throughput determination of ultra-low concentrations of LAG078, a lipid modulator, in human plasma

2005 ◽  
Vol 37 (5) ◽  
pp. 1039-1048
Author(s):  
Tapan K. Majumdar ◽  
Ray Bakhtiar ◽  
Cindy Chen ◽  
Luis Ramos ◽  
Francis L.S. Tse
Keyword(s):  
Human Plasma ◽  
High Throughput ◽  
Low Concentrations

2-(2'- Chloro Phenyl)- 5- (2'-Hydroxyl Phenyl)-1,3,4-Oxadiazole as a Florescent Probe for DNA Determination

2011 ◽  
Vol 301-303 ◽  
pp. 361-365
Author(s):  
Mei Ding ◽  
Ying Jie Lei ◽  
Ou Yang Jie
Keyword(s):  
Experimental Data ◽  
Fluorescence Quenching ◽  
Quantitative Determination ◽  
Fluorescent Probe ◽  
Fluorescence Intensity ◽  
Dna Analysis ◽  
Fluorescence Spectrometry ◽  
Experimental Conditions ◽  
Convenient Synthesis

In recent years, fluorescence spectrometry was widely used in quantitative determination of DNA. In this paper, a convenient synthesis of a new fluorescent 2-(2'- Chloro phenyl)- 5- (2'- hydroxyl phenyl)-1,3,4-oxadiazole (HOXD) was realized. Experimental data showed that fluorescence of HOXD could be quenched by DNA and the decreased fluorescence intensity of HOXD resulting from fluorescence quenching is proportional to DNA concentrations suggesting that HOXD could be used as a new fluorescent probe for quantitative determination of DNA. Optimal experimental conditions for DNA analysis were also studied in the paper.

scholarly journals Micellar Enhanced Spectrofluorimetric Method for the Determination of Ponatinib in Human Plasma and Urine via Cremophor RH 40 as Sensing Agent

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Hany W. Darwish ◽  
Ahmed H. Bakheit ◽  
Ali Saber Abdelhameed ◽  
Amer S. AlKhairallah
Keyword(s):  
Human Plasma ◽  
Fluorescence Intensity ◽  
Limit Of Detection ◽  
Biological Fluids ◽  
Great Success ◽  
Limit Of Quantification ◽  
Human Plasma And Urine ◽  
Spectrofluorimetric Method ◽  
Fluorescence Characteristics

An impressively simple and precise spectrofluorimetric procedure was established and validated for ponatinib (PTB) quantitation in biological fluids such as human plasma and human urine. This method depends on examining the fluorescence characteristics of PTB in a micellar system of Cremophor RH 40 (Cr RH 40). Cr RH 40 enhanced the intrinsic fluorescence of PTB distinctly in aqueous water. The fluorescence spectra of PTB was recorded at 457 nm following its excitation at 305 nm. Maximum fluorescence intensity was attained by addition of 0.7 mL of Cr RH 40 and one mL of phosphate buffer to PTB aliquots and then dilution with distilled water. There is a linear relationship between the fluorescence intensity of PTB and its concentration over the range 5–120 ngmL−1, with limit of detection and limit of quantification equal to 0.905 ngmL−1and 2.742 ngmL−1, respectively. The accuracy and the precisions of the proposed method were checked and gave adequate results. The adopted method was applied with a great success for PTB quantitation in different biological matrices (spiked human plasma and urine) giving high recovery values.

scholarly journals Spectrofluorometric Determination of Citalopram in Pharmaceutical Preparations and Spiked Human Plasma Using Organized Media

2006 ◽  
Vol 89 (5) ◽  
pp. 1288-1295 ◽  
Author(s):  
Dina T El-Sherbiny
Keyword(s):  
Aqueous Solution ◽  
Human Plasma ◽  
Fluorescence Intensity ◽  
Pharmaceutical Preparations ◽  
Citrate Buffer ◽  
Acidic Aqueous Solution ◽  
Sds Micelles ◽  
Spectrofluorometric Determination ◽  
Organized Media

Abstract The native fluorescence of citalopram (CIT) was (obtained in citrate buffer of pH 6.5 with and without β-cyclodextrin (β-CD) or sodium dodecyl sulfate (SDS) as fluorescence enhancers at 305 nm using 242 nm for excitation. Micellar systems of ionic and nonionic surfactants were investigated by measuring the fluorescence intensity of the analyte-surfactant system. In slightly acidic aqueous solution of pH 6.5, CIT was better incorporated in CDs and SDS micelles. The luminescence emission from CIT was found to be greatly enhanced by SDS micelles. The fluorescence intensity enhancements in CDs medium and in SDS as ionic surfactant relative to slightly acidic aqueous solution were 125 and 250%, respectively. Organized media-enhanced spectroflourometric methods were developed for the determination of CIT, in pure form as well as in pharmaceutical preparations. The fluorescence intensity-concentration plots were rectilinear over the ranges 0.06 to 0.64, 0.04 to 0.40, and 0.02 to 0.26 μg/mL with lower detection limits of 0.02, 0.01, and 0.007 μg/mL, either in citrate buffer only or in β-CD and SDS as organized media, respectively. Furthermore, the high sensitivity attained by using SDS as organized medium allowed in vitro spectrofluorometric determination of CIT in spiked human plasma. Interference from endogenous amino acids has been overcome by using the solid-phase extraction technique; the mean recovery (n = 5) was 100.1 ± 0.8%

A direct sensitized fluorimetric determination of 5,10,15,20-tetra(m-hydroxyphenyl)chlorin [m-THPC (Foscan)®] in human plasma using a cyclodextrin inclusion complex

The Analyst ◽  
2001 ◽  
Vol 126 (6) ◽  
pp. 923-927 ◽  
Author(s):  
Marie-Catherine Desroches ◽  
Athena Kasselouri ◽  
Pierre Chaminade ◽  
Patrice Prognon ◽  
Olivier Bourdon ◽  
...  
Keyword(s):  
Inclusion Complex ◽  
Human Plasma ◽  
Fluorimetric Determination ◽  
Cyclodextrin Inclusion ◽  
Cyclodextrin Inclusion Complex

scholarly journals Masking Ability of Various Metal Complexing Ligands at 1.0 mM Concentrations on the Potentiometric Determination of Fluoride in Aqueous Samples

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Sakuni M. De Silva ◽  
Samitha Deraniyagala ◽  
Janitha K. Walpita ◽  
Indira Jayaweera ◽  
Saranga Diyabalanage ◽  
...  
Keyword(s):  
Experimental Data ◽  
Natural Waters ◽  
Ethylenediaminetetraacetic Acid ◽  
Aqueous Samples ◽  
Metal Chelating ◽  
Low Concentrations ◽  
Masking Agents ◽  
Potentiometric Analysis ◽  
Common Anion

Fluoride is a common anion present in natural waters. Among many analytical methods used for the quantification of fluoride in natural waters, potentiometric analysis is one of the most widely used methods because of minimum interferences from other ions commonly present in natural waters. The potentiometric analysis requires the use of ionic strength adjusting buffer abbreviated as TISAB to obtain accurate and reproducible data. In most of the reported literature, higher concentrations of strong metal chelating ligands are used as masking agents generally in the concentration range of 1.0 to 0.01 M. In the present study, effectiveness of the masking agents, phosphate, citrate, CDTA ((1,2-cyclohexylenedinitrilo)tetraacetic acid), EDTA (ethylenediaminetetraacetic acid) HE-EDTA ((hydroxyethyl)ethylenediaminetriacetic acid)), triethanolamine, and tartaric acid at 1.0 mM in TISAB solutions was investigated. The experimental data were compared with a commercially available WTW 140100 TISAB solution as the reference buffer. According to the experimental data, the reference buffer always produced the highest fluoride concentrations and the measured fluoride concentrations were in the range of 0.611 to 1.956 mg/L. Out of all the masking agents investigated, only CDTA performed marginally well and approximately a quarter of the samples produced statistically comparable data to the reference buffer. All the other masking agents produced significantly low concentrations compared to the reference buffer. The most probable reasons for the underestimation of fluoride concentrations could be shorter decomplexing time and lower masking agent concentrations.

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