Prospects and limitations of a clay-enabled pre-concentration method for spectrophotometric quantification

Tsotsou, Georgia Eleni; Mazarakis, Anastasios Phoebus

doi:10.1016/j.clay.2023.106829

Cited by 3 publications

(7 citation statements)

References 36 publications

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“…2). A similar trend was observed upon quantitative analysis using the delamination-based protocol (10).…”

Section: Resultssupporting

confidence: 78%

“…Based on the results presented above, there is a good agreement between the camera-enabled colour intensity measurement and the established absorbance measurement after delamination (10), for all model, structurally diverse, chemical entities. We next calculated the lower limit of linear response for each studied chemical entity (Table 1).…”

Section: Resultssupporting

confidence: 62%

“…4b). Such a two-stage behaviour was observed upon quanti cation using the delamination-based technique (10). Colouration of the supernatant was observed at pH 10.0, however no supernatant colouration was apparent at pH 2.75, since only the anionic form of methyl red at basic pH is released to the supernatant, being repelled by the clay.…”

Section: Resultsmentioning

confidence: 94%

“…In a previous work we demonstrated pre-concentration of methyl red, Co II , and topotecan, among other model chemical entities, from dilute aqueous solution in the presence of Bentone LT. Treatment of Bentone LT-adsorbate with a suitable solvent resulted in clay delamination, where the adsorbate apparently remained adsorbed onto delaminated clay particles of nanodimensions (10). In this particular state, the adsorbate was available to participate in a chromogenic reaction allowing its photometric quanti cation, while interference from nanomaterial in suspension was acceptable (9).…”

Section: Resultsmentioning

confidence: 99%

“…For instance, we observed that there is very limited colour generation in an ion pair formation-based chromogenic assay, most likely since the positively charged moiety on the adsorbate which should form the ion pair, is consumed through direct interaction with the clay negatively charged sites. Poor chromogenic reaction yield may also be the result of the negatively charged chromogenic reagent being repulsed by the clay (10). In such cases, adsorbate release from the pellet should allow the chromogenic reaction to take place in the supernatant, with subsequent colour monitoring in the supernatant.…”

Section: Resultsmentioning

confidence: 99%

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Smartphone-based colourimetric detection of analytes after pre-concentration onto a hectorite clay-hydroxyethylcellulose hybrid

Mazarakis

Tsotsou

2023

Preprint

Self Cite

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This paper describes a new, smartphone-enabled quantitative analysis format, based on analyte pre-concentration by adsorption onto Bentone LT. Bentone LT pellet isolation comes after adsorption, followed by in-situ application of an analyte-selective chromogenic reaction. Resulting pellet colouration is captured by the phone’s integrated camera and assessed using the free open-source image processing software, ImageJ. Responses are calibrated and quantified. We here demonstrate the extended applicability of the proposed methodology for the smartphone-based quantification of specific model analytes. The smartphone-based assay is reliable in quantifying model analytes, alone or in mixture, from dilute aqueous solutions and depicts accurately the adsorption behaviour followed photometrically in solution. Its quantification capability was found to extend below that of the respective chromogenic reaction in solution. It is likely that the applicability of the proposed quantitative analysis format extends to other analytes where analyte-specific colour formation is feasible.

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“…2). A similar trend was observed upon quantitative analysis using the delamination-based protocol (10).…”

Section: Resultssupporting

confidence: 78%

Section: Resultssupporting

confidence: 62%

Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

Smartphone-based colourimetric detection of analytes after pre-concentration onto a hectorite clay-hydroxyethylcellulose hybrid

Mazarakis

Tsotsou

2023

Preprint

Self Cite

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Cadmium sensing with bentonite-modified carbon paste electrode: electrochemical insights

Mourak,

Hajjaji,

Idoulhi

et al. 2023

J Solid State Electrochem

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Smartphone-Based Colourimetric Detection of Methyl Red, Co(II), Uric Acid, and Topotecan after Pre-concentration onto a Hectorite Clay-Hydroxyethylcellulose Hybrid

Mazarakis,

Tsotsou

2024

CAC

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Objective: This paper describes a new, digital image colourimetry-based format for the quantification of analytes in an aqueous solution. Method: The proposed method is based on analyte pre-concentration by adsorption onto Bentone LT. Bentone LT pellet isolation comes after adsorption, followed by in-situ application of an analyteselective chromogenic reaction. The resulting pellet colouration is captured by the phone’s integrated camera and assessed using the free open-source image processing software, ImageJ. Responses are calibrated and quantified. Results: We tested the applicability of the proposed methodology for the quantification of specific model analytes which are of concern in environmental matrices (methyl red, Co(II), uric acid, topotecan). The smartphone-based assay was proven reliable in quantifying the model analytes (standard recovery of 82-116%), alone or in mixture, from dilute aqueous solutions and was found to depict accurately the adsorption behaviour followed photometrically in solution. Lower limit of linearity was calculated at 0.05, 0.11, 0.85 and 0.20 μg/mL for methyl red, Co(II), uric acid, and topotecan, respectively. The proposed format was found superior when compared to alternative published photometric/ colourimetric assays in terms of the lower limit of linearity. In the presence of possible adsorption interferents, the lower limit of linear response was shifted to slightly higher concentrations for topotecan i.e. from 0.2 μg/mL to 0.5 μg/mL. Conclusion: We here demonstrate the extended applicability of the proposed methodology for the smartphone-based quantification of the specific model analytes. The applicability of this analysis format likely extends to other analytes, where analyte-specific colour formation is feasible.

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Prospects and limitations of a clay-enabled pre-concentration method for spectrophotometric quantification

Cited by 3 publications

References 36 publications

Smartphone-based colourimetric detection of analytes after pre-concentration onto a hectorite clay-hydroxyethylcellulose hybrid

Smartphone-based colourimetric detection of analytes after pre-concentration onto a hectorite clay-hydroxyethylcellulose hybrid

Cadmium sensing with bentonite-modified carbon paste electrode: electrochemical insights

Smartphone-Based Colourimetric Detection of Methyl Red, Co(II), Uric Acid, and Topotecan after Pre-concentration onto a Hectorite Clay-Hydroxyethylcellulose Hybrid

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