Impact of humic acids on fluorimetric determination of phenol in aqueous solutions

The photoluminescence of carbon quantum dots synthesized from natural honey and mixtures of honey and sugar has been studied. An increase in the sugar content leads to a decrease in the photoluminescence intensity without changing the shape of the luminescence spectrum of these quantum dots aqueous solutions, which is associated with a decrease in the yield of their synthesis in the sugar presence. The discovered effect can be used to detect sugar in honey. When examining five different market samples of flower honey using this method, two of them showed a significant decrease in the photoluminescence intensity. A laboratory test for compliance with GOST 19792-2017 Standard requirements established an excess of the sucrose content in these samples. Luminescent determination of sugar in honey does not require complicated equipment and can be used to develop a new analytical method for determining the sugar content in counterfeit natural honey.

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Brown coals and lignites. Determination of humic acids

10.3403/30274555u ◽

2015 ◽

Keyword(s):

Humic Acids ◽

Brown Coals

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Simple Method for Spectrophotometric Determination of Benzidine in Aqueous Solutions by Coupling with Β-Naphthol

Journal of Al-Nahrain University-Science ◽

10.22401/jnus.14.2.05 ◽

2011 ◽

Vol 14 (2) ◽

pp. 43-50

Author(s):

Ameera .H. Hamed ◽

Keyword(s):

Aqueous Solutions ◽

Spectrophotometric Determination ◽

Simple Method

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The fluorimetric determination of cerium and terbium

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19890616 ◽

1989 ◽

Vol 54 (3) ◽

pp. 616-621 ◽

Cited By ~ 3

Author(s):

Záviš Holzbecher

Keyword(s):

Rare Earth ◽

Detection Limit ◽

Rare Earth Elements ◽

Fluorimetric Determination ◽

Fluorescence Maximum ◽

Relative Standard ◽

And Shifts ◽

Hcl Medium ◽

Fold Excess

It has been found that phosphoric acid decreases the first excitation maximum of Ce(III) at 256 nm, increases the second excitation maximum at 297 nm and shifts the fluorescence maximum from 350 to 346 nm. Under optimum conditions, with λexc = 297 nm and λem = 346 nm, Ce(III) can be determined fluorimetrically with a detection limit of 1.2 ng ml-1 in 12M-H3PO4 medium. No interference was observed from a 20-200 fold excess of HCl, H2SO4, Na, K, NH4+, Al and the rare earth elements. HNO3 interferes and Ce(IV) and Fe(III) interfere strongly. It follows from the stereofluorograms of Ce and Tb that the spectra of the two elements are practically independent. The detection limit for Tb(III) in 0.02-2.5M-H2SO4 medium for λexc = 222 nm and λem = 494 nm is 33 ng ml-1. No interference was observed from a 5-20 fold excess of Al3+ and the other rare earth elements. The determination is slightly less sensitive in H3PO4 or HCl medium. The relative standard deviation of the measurement for 10 ng ml-1 Ce(III) or 50 ng ml-1 Tb(III) is about 3%.

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Sorption of Lead by the Selective Ion Exchanger Ostsorb DETA

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19921393 ◽

1992 ◽

Vol 57 (7) ◽

pp. 1393-1404 ◽

Cited By ~ 3

Author(s):

Ladislav Svoboda ◽

Jan Uhlíř ◽

Zdeněk Uhlíř

Keyword(s):

Phosphoric Acid ◽

Aqueous Solutions ◽

Functional Groups ◽

Ion Exchanger ◽

Preconcentration Procedure ◽

Bead Cellulose

The properties of Ostsorb DETA, a selective ion exchanger based on modified bead cellulose with chemically bonded diethylenetriamine functional groups, were studied, and its applicability to the preconcentration of trace amounts of lead from aqueous solutions was verified. The conditions of the preconcentration procedure in the column and batch modes were optimized for this purpose. The results obtained were applied to the determination of lead in phosphoric acid.

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