High photoluminescent TPA and the ratiometric sensor for free chlorine

Fang, Qingqing; Wang, Qian; Lin, Wei; Xu, You; Dong, Yongqiang; Chi, Yuwu

doi:10.1016/j.snb.2017.01.070

Cited by 21 publications

(9 citation statements)

References 27 publications

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“…For example, Fang et al experimented with TPA molecule for free chlorine sensing. [86] Specifically, the TPA molecule (CA-Cys) was synthesized from the condensation of CA and L-cysteine, and the obtained TPA molecule exhibited strong blue fluorescence (QY 90.5%) with a maximum excitation at 345 nm and a maximum emission at 415 nm. It was found that the fluorescence signal of TPA can be quenched sensitively by the free chlorine, which was determined by the oxidation of sulfur atom of TPA into sulfoxiby chlorine.…”

Section: Citrate-based Molecular Fluorophoresmentioning

confidence: 99%

Citrate‐Based Fluorescent Biomaterials

Shan

Hsieh

Bai

et al. 2018

Adv Healthcare Materials

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Fluorescence imaging has emerged as a promising technique for monitoring and assessing various biologically relevant species in cells and organisms, driving the demand for effective fluorescent agents with good biocompatibility and high fluorescence performance. However, traditional fluorescent agents, such as quantum dots (QDs) and organic dyes, either suffer from toxicity concerns or poor fluorescence performance (e.g., low photobleaching-resistance). In this regard, citrate-based fluorescent biomaterials, which are synthesized from the natural and biocompatible precursor of citric acid (CA), have become competitive alternatives for fluorescence imaging owing to their biocompatibility, cost effectiveness, straightforward synthetic routes, flexible designability, as well as strong fluorescence with adjustable excitation/emission wavelengths. Accordingly, numerous citrate-based biomaterials, including carbon dots (CDs), biodegradable photoluminescent polymers (BPLPs), and small molecular fluorophores, have been developed and researched in the past few decades. This review discusses recent progress in the research and development of citrate-based fluorescent materials with emphasis on their design and synthesis considerations, material properties, fluorescence properties and mechanisms, as well as biomedical applications. It is expected that this review will provide an insightful discussion on the citrate-based fluorescent biomaterials, and lead to innovations for the next generation of fluorescent biomaterials and fluorescence-based biomedical technology.

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Section: Citrate-based Molecular Fluorophoresmentioning

confidence: 99%

Citrate‐Based Fluorescent Biomaterials

Shan

Hsieh

Bai

et al. 2018

Adv Healthcare Materials

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“…9 The latter is also known as colorimetry, since the resulting color change in the visible region can also be judged by the eye. Free chlorine concentration can also be measured by an optical response to addition of an indicator reagent through methods such as colorimetry, 10 photoluminescence, 11 and chemiluminescence. 12 The indicator/analyte mixture resulting from these measurements cannot be disposed into the environment.…”

Section: ■ Introductionmentioning

confidence: 99%

Reagent-Free Quantification of Aqueous Free Chlorine via Electrical Readout of Colorimetrically Functionalized Pencil Lines

Mohtasebi

Broomfield

Chowdhury

et al. 2017

ACS Appl. Mater. Interfaces

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Colorimetric methods are commonly used to quantify free chlorine in drinking water. However, these methods are not suitable for reagent-free, continuous, and autonomous applications. Here, we demonstrate how functionalization of a pencil-drawn film with phenyl-capped aniline tetramer (PCAT) can be used for quantitative electric readout of free chlorine concentrations. The functionalized film can be implemented in a simple fluidic device for continuous sensing of aqueous free chlorine concentrations. The sensor is selective to free chlorine and can undergo a reagent-free reset for further measurements. Our sensor is superior to electrochemical methods in that it does not require a reference electrode. It is capable of quantification of free chlorine in the range of 0.1-12 ppm with higher precision than colorimetric (absorptivity) methods. The interactions of PCAT with the pencil-drawn film upon exposure to hypochlorite were characterized spectroscopically. A previously reported detection mechanism relied on the measurement of a baseline shift to quantify free chlorine concentrations. The new method demonstrated here measures initial spike size upon exposure to free chlorine. It relies on a fast charge built up on the sensor film due to intermittent PCAT salt formation. It has the advantage of being significantly faster than the measurement of baseline shift, but it cannot be used to detect gradual changes in free chlorine concentration without the use of frequent reset pulses. The stability of PCAT was examined in the presence of free chlorine as a function of pH. While most ions commonly present in drinking water do not interfere with the free chlorine detection, other oxidants may contribute to the signal. Our sensor is easy to fabricate and robust, operates reagent-free, and has very low power requirements and is thus suitable for remote deployment.

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“…While offline methods are well-established, recent work has focussed on improving continuous online water quality analysis. Colorimetric, 70,71 photoluminescence, 28 chemoluminescence, 25 or uorescence 72,73 based optical online free chlorine monitors can be optimized for high 70,73 or low 25,28,71,72 detection ranges depending on application. Detection limits around 10 ppb are comfortably achievable, but all these methods require the use of fresh reagents for each sample point.…”

Section: Discussionmentioning

confidence: 99%

“…14 Examples of other reagents for colorimetric detection include ABTS, 22 Michler's thioketone, 23 and syringaldazine. 24 Chemiluminescence [25][26][27] and uorescence 28,29 are also successful optical sensing strategies. Multiple electrochemical sensors have also been developed, based on the principles of voltammetry 30,31 and amperometry.…”

Section: Introductionmentioning

confidence: 99%