A continuous method incorporating β-cyclodextrin modified CdSe/ZnS quantum dots for determination of ascorbic acid

Abstract

A flow system using water-soluble CdSe/ZnS quantum dots modified with b cyclodextrin (b-CD) was developed for the determination of ascorbic acid. The system was based on the quenching effect produced by ascorbic acid on the fluorescence intensity of surface modified QDs with b-CD. Under the optimized conditions, the relationship between the fluorescence intensity of the b-CD-CdSe/ZnS-QDs and ascorbic acid concentration was linear in the 2-100 mg L À1 range. LOD and LOQ values of 0.6 and 2.0 mg L À1 were obtained, respectively. A reproducibility of 4.2% in terms of relative standard deviation (3.2% under repeatability conditions) was obtained. The proposed methodology was applied to the determination of ascorbic acid in fruit juices and a pharmaceutical formulation. The results obtained were in good agreement with both the titrimetric method and the amount specified by the manufacturer, thus indicating the usefulness of the proposed methodology in the alimentary field.

Interactions of Native Cyclodextrins with Metal Ions and Inorganic Nanoparticles: Fertile Landscape for Chemistry and Materials Science

“…In a similar manner, water-soluble CD-modified CdSe/ZnS QDs were utilized as selective fluorescent assays for the recognition of amino acid enantiomers. , The selective enantiorecognition of l -Penicillamine and d -Penicillamine was accomplished by host–guest interaction between the penicillamines and the β-CD pockets on the QDs (Figure c). Another sensing system based on β-CD and CdSe/ZnS QDs was developed for determination of ascorbic acid (Figure d) . In this case, the fluorescence of the QDs was quenched by the oxidized ascorbic acid.…”

“…(d) Determination of ascorbic acid. (Reprinted with permission from ref . Copyright 2015 Royal Chemical Society.…”

Analysis of penicillamine using Cu-modified graphene quantum dots synthesized from uric acid as single precursor

“…Among those, photoluminescent nanomaterials have drawn increasing attention because they have the potential to impact a wide number of fields ranging from optoelectronics to bio-analysis [5] , [6] . While the synthesis and applications of semiconductor quantum dots (S-QDs) [2] , [7] , [8] , [9] , [10] , [11] have gained abundant recognition [11] , their toxicity can severely impair their use, especially for biomedical applications. Addressing this limitation, carbon-based QDs (CQDs) present themselves as an attractive alternative.…”

A highly sensitive switch-on spectrofluorometric method for determination of ascorbic acid using a selective eco-friendly approach

“…The reported spectrofluorometric methods employed fluorescent dyes, or quantum dots as shown in Table 5 . These methods suffered from a number of limitations such as the complicated procedures [14] , [39] , [40] , the long reaction time [15] , the high temperature required [18] , [41] , [42] and the necessity for catalyst addition. Compared with these reported methods, our proposed method is easier, faster, and does not require heating or catalysis due to the instantaneous reaction and the high yield.…”

“…A number of techniques have been utilized for determination of ASC in different matrices, including UV/visible spectroscopy [9] , [10] , [11] , spectroflurometry [12] , [13] , [14] , [15] , [16] , [17] , [18] , high performance liquid chromatography [19] , [20] , and electrochemistry [21] , [22] , [23] . Compared with other techniques, spectroflurometry is more sensitive and more selective than UV/visible spectroscopy and does not require sophisticated instruments such as HPLC and LC/MS [24] , [25] .…”