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Romero V, Sant'Anna C, Lavilla I, Bendicho C. Fluorescent paper-based sensor integrated with headspace thin-film microextraction for the detection of acyclic N-nitrosamines following in situ photocatalytic decomposition. Anal Chim Acta 2023; 1239:340729. [PMID: 36628727 DOI: 10.1016/j.aca.2022.340729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/16/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022]
Abstract
BACKGROUND In this work, a novel analytical approach based on the photocatalytic decomposition of N-nitrosamines combined with headspace thin-film microextraction of the generated nitrogen oxides such as NO has been developed for the determination of the acyclic N-nitrosamine fraction in drinking water samples. A hydrophilic cellulose substrate modified with fluorescent silver nanoclusters (Ag NCs) was used both as extractant and sensing platform. A quenching effect of Ag NCs fluorescence occurs as the concentration of N-nitrosamines increases. Front-face fluorescence spectroscopy with a solid sample holder was employed for directly measuring the fluorescence quenching onto the cellulose substrate. RESULTS In order to achieve an optimal analytical response, different parameters involved in the photocatalytic reaction as well as those concerning the microextraction step were fully investigated. It is demonstrated that the photodegradation rate of cyclic N-nitrosamines at acidic pH is much lower than that of acyclic ones, which can be the basis for the determination of the later fraction in waters. Under optimal conditions, a detection limit for the acyclic N-nitrosamine fraction around 0.08 μg L-1 using N-nitrosodimethylamine (NDMA) as model compound for calibration was obtained. Several drinking waters were spiked with acyclic N-nitrosamines showing recoveries in the range of 98-102% with a relative standard deviation of 3-4% (N = 3). SIGNIFICANCE AND NOVELTY N-nitrosamines generated as by-products during disinfection processes applied to water cause multiple adverse effects on human health being classified as potential human carcinogens. This study highlights the suitability of a fluorescent paper-based sensor for the rapid analysis of the acyclic N-nitrosamine fraction (i.e. the most abundant fraction) as a total index in drinking water, being useful as screening tool before exhaustive chromatographic analysis, which saves costs, time and reduces waste generation.
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Affiliation(s)
- Vanesa Romero
- Centro de Investigación Mariña, Universidade de Vigo, Departamento de Química Analítica y Alimentaria, Grupo QA2, 36310, Vigo, Spain.
| | - Carolina Sant'Anna
- Centro de Investigación Mariña, Universidade de Vigo, Departamento de Química Analítica y Alimentaria, Grupo QA2, 36310, Vigo, Spain
| | - Isela Lavilla
- Centro de Investigación Mariña, Universidade de Vigo, Departamento de Química Analítica y Alimentaria, Grupo QA2, 36310, Vigo, Spain
| | - Carlos Bendicho
- Centro de Investigación Mariña, Universidade de Vigo, Departamento de Química Analítica y Alimentaria, Grupo QA2, 36310, Vigo, Spain.
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Moreira FTC, Correia BP, Sousa MP, Sales GF. Colorimetric cellulose-based test-strip for rapid detection of amyloid β-42. Mikrochim Acta 2021; 188:334. [PMID: 34498145 DOI: 10.1007/s00604-021-04996-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 08/13/2021] [Indexed: 11/30/2022]
Abstract
An innovative sensing assay is described for point-of-care (PoC) quantification of a biomarker of Alzheimer's disease, amyloid β-42 (Aβ-42). This device is based on a cellulose paper-dye test strip platform in which the corresponding detection layer is integrated by applying a molecularly imprinted polymer (MIP) to the cellulose paper surface. Briefly, the cellulose paper is chemically modified with a silane to subsequently apply the MIP detection layer. The imprinting process is confirmed by the parallel preparation of a control material, namely a non-imprinted polymer (NIP). The chemical changes of the surface were evaluated by Fourier transform infrared spectroscopy (FTIR), contact angle, and thermogravimetric analysis (TG). Proteins and peptides can be quantified by conventional staining methods. For this purpose, Coomassie blue (CB) was used as a staining dye for the detection and quantification of Aβ-42. Quantitative determination is made possible by taking a photograph and applying an appropriate mathematical treatment to the color coordinates provided by the ImageJ program. The MIP shows a linear range between 1.0 ng/mL and 10 μg/mL and a detection limit of 0.71 ng/mL. Overall, this cellulose-based assay is suitable for the detection of peptides or proteins in a sample by visual comparison of color change. The test strip provides a simple, instrument-free, and cost-effective method with high chemical stability, capable of detecting very small amounts of peptides or proteins in a sample, and can be used for the detection of any (bio)molecule of interest.
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Affiliation(s)
- Felismina T C Moreira
- BioMark@ISEP, School of Engineering, Polytechnic of Porto, R. Dr. António Bernardino de Almeida, 431, 4249-015, Porto, Portugal. .,CEB, Centre of Biological Engineering, Minho University, Braga, Portugal.
| | - Barbara P Correia
- BioMark@ISEP, School of Engineering, Polytechnic of Porto, R. Dr. António Bernardino de Almeida, 431, 4249-015, Porto, Portugal.,CEB, Centre of Biological Engineering, Minho University, Braga, Portugal
| | - Mariana P Sousa
- BioMark@ISEP, School of Engineering, Polytechnic of Porto, R. Dr. António Bernardino de Almeida, 431, 4249-015, Porto, Portugal.,CEB, Centre of Biological Engineering, Minho University, Braga, Portugal
| | - Goreti F Sales
- CEB, Centre of Biological Engineering, Minho University, Braga, Portugal.,BioMark@UC, Faculty of Sciences and Technology, University of Coimbra, R. Sílvio Lima, pólo II, 3030-790, Coimbra, Portugal
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