Application of single and dual fluorophore-based pH sensors for determination of milk quality and shelf life using a fibre optic spectrophotometer

Choudhary, Sandeep; Joshi, Bhavana; Pandey, Gaurav; Joshi, Abhijeet

doi:10.1016/j.snb.2019.126925

Cited by 28 publications

(20 citation statements)

References 18 publications

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“…This indicated that the storable N-CQDs could reduce the reagent preparation time and simplify the experimental steps. This FL method was more credible and more reproducible, compared to other detection methods for milk acidity [7,8,13]. As a result, the FL method based on acidity-responsive N-CQDs can be successfully used to detect different levels of acidity in milk, by investigating the FL characteristics of milk samples without any pre-processing steps.…”

Section: N-cqds-based Sensitive Fl Assaymentioning

confidence: 94%

“…Traditional methods for the detection of milk acidity include neutralization titrations (phenolphthalein indicator titration) [7] and potentiometers (pH meter) [8,9]. These methods have been successfully applied in the accurate detection of milk freshness [7,9].…”

Section: Introductionmentioning

confidence: 99%

“…Eye-readable sensors have attracted increasing attention for their simple and convenient assessment, without the need for electronics and external digital readouts [13,14]. Such sensors have been fabricated using organic fluorophores, such as fluorescein isothiocyanate (FITC) [8] and succinimide substituted 2-(2 -hydroxyphenyl) benzothiazole derivative (BTSA) [15]. These fluorescent dyes, which have good fluorescence emission performance, often suffer from certain disadvantages, including poor biocompatibility, broad red-tailed photoluminescence spectra, and high susceptibility to photobleaching [16], prompting us to improve the fluorescence properties of eye-readable sensors.…”

Section: Introductionmentioning

confidence: 99%

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Easy-to-Use Visual Sensing System for Milk Freshness, Sensitized with Acidity-Responsive N-Doped Carbon Quantum Dots

Zhang

et al. 2022

Foods

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This study established a flexible and eye-readable sensing system for the easy-to-use, visual detection of milk freshness, using acidity-responsive N-doped carbon quantum dots (N-CQDs). N-CQDs, rich in amino groups and with characteristic acidity sensitivity, exhibited high relative quantum yields of 25.2% and an optimal emission wavelength of 567 nm. The N-CQDs fluorescence quenching upon the dissociated hydrogen ions (H+) in milk and their reacting with the amino groups produced an excellent linear relation (R2 = 0.996) between the fluorescence intensity and the milk acidity, which indicated that the fluorescence of the N-CQDs was highly correlated with milk freshness. Furthermore, a fluorescence sensor was designed by depositing the N-CQDs on filter-papers and starch-gel films, to provide eye-readable signals under UV light. A fluorescence colorimetric card was developed, based on the decrease in fluorescence brightness as freshness deteriorated. With the advantages of high sensitivity and eye readability, the proposed sensor could detect spoiled milk in advance and without any preprocessing steps, offering a promising method of assessing food safety.

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Section: N-cqds-based Sensitive Fl Assaymentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Easy-to-Use Visual Sensing System for Milk Freshness, Sensitized with Acidity-Responsive N-Doped Carbon Quantum Dots

Zhang

et al. 2022

Foods

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“…Consumed milk largely for high nutritional value but limited shelf life, as it cannot keep up quality for more than (2 -3) days [2]. Milk and milk products are susceptible to lightinduced oxidation reactions, which can negatively affect odor and flavor Photooxidation of milk occurs under the presence of light (artificial, sunlight) [3], is an indicating of degradation of milk during transportation [4]. Exposure of milk to light facilitates the degradation of amino acids and vitamin A, and fat oxidation [5].…”

Section: Introductionmentioning

confidence: 99%

Study of the effect of sunlight on the chemical composition of Milk

Jameel

2020

Journal of Bioscience and Applied Research

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Light-induced degradation reactions make a serious problem for the milk because of the development of flavors and a decrease in nutritional quality, materials of Packaging are important to avoid this particular degradation of milk. In this study, were divided milk into two groups (light exposed ) + (light protected (foil overwrap)) under the same cooling conditions at 3°C for 15 days, those expectant during the show in stores of retail and markets. And the effect of this on the chemical composition of milk, the results of my study then showed that the appropriate blocking light with an overwrap of foil helped inhibit lipid and protein Lipolysis compared with the samples exposed to light under the same cooling conditions. Therefore, the appropriate Blocking of visible light with foil overwrap can increase milk's shelf life.

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“…As one of the most important parameters, pH plays a crucial role in various fields like human health care, biomedical analysis, environmental monitoring, chemical and biochemical reaction monitoring and control, and electrochemical sensing 1–5 . The development of convenient and effective methods for detection of pH thus attracted increasing attention and among the multiple pH determination methodologies fluorescent pH probes have emerged as an efficient method which has aroused much interest from scientists because these probes exhibit advantages of high selectivity and sensitivity, rapid response, low cost, simplicity, and non‐invasiveness 6‒8 .…”

Section: Introductionmentioning

confidence: 99%

A novel reaction‐based fluorescent probe sensitive to pH changes in multiple intervals

Жен

Zheng

et al. 2020

Coloration Technology

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A new coumarin derivative containing both imine bond and amide moiety was synthesised. It was used as a reaction‐based pH probe and was sensitive to pH changes in the intervals 1.50–4.10 and 10.20–12.86. In the pH range 1.50–4.10, the ultraviolet‐visible (UV‒vis) absorption band of the probe gradually shifted from 353 nm to 340 nm with decrease in the pH value. The colour changed from pale yellow fluorescence at pH 4.10 to blue fluorescence at pH 1.50. Meanwhile the fluorescence emission band at 501 nm gradually shifted to 560 nm accompanying a gradual enhancing in the emission intensity. This pH response is caused by the hydrolysis of the imine bond in the probe under acidic conditions (pH 1.50–4.10). The colourless probe solution turned yellow at pH range 10.20–12.86. Bathochromic shift of the fluorescence band from 501 nm gradually to 550 nm was observed with the increase of pH value from 10.20 to 12.86 accompanying a gradual enhancement of the fluorescence emission intensity, indicating that the new compound serves as a fluorescent pH probe at pH range 10.20–12.86 through a deprotonation process. Under strongly alkaline conditions with pH larger than 12.86, hydrolysis of the lactone structure in the probe occurred to produce non‐fluorescent species.

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Application of single and dual fluorophore-based pH sensors for determination of milk quality and shelf life using a fibre optic spectrophotometer

Cited by 28 publications

References 18 publications

Easy-to-Use Visual Sensing System for Milk Freshness, Sensitized with Acidity-Responsive N-Doped Carbon Quantum Dots

Easy-to-Use Visual Sensing System for Milk Freshness, Sensitized with Acidity-Responsive N-Doped Carbon Quantum Dots

Study of the effect of sunlight on the chemical composition of Milk

A novel reaction‐based fluorescent probe sensitive to pH changes in multiple intervals

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