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Tartrazine is used as a synthetic colorant to improve the color of food. Excessive intake of tartrazine will seriously harm human health. In this paper, a green and facile one-pot hydrothermal approach is proposed for the preparation of sulfur-doped carbon quantum dots (S-CQDs) with Alternanthera philoxeroides (AP) powder and thiourea. The S-CQDs w...
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... Continuous consumption of food items with these preservatives predisposes consumers to ailments associated with the presence of these substances in food items and drinks. Allergies, diarrhea, cancer, migraine, liver and kidney damage are few of the life-threatening ailments associated with long term consumption of food items containing additives such as tartrazine (75,76). To avoid human exposure to this risk, sensors have been developed to determine the concentration of these substances in food and drink for quality assurance purposes. ...
... Table 5 depicts the figures of merit of the fluorescence and electrochemical sensors for the determination of food additives and heavy metals detection . Fluorescence sensors made from CQDs or CQDs-based fluorescent probes such as CQDs (from citrus peels), N-CQDs, N,Cl-CQDs, CQDs (crayfish shell), CQDs (from vehicle exhaust soot), S-CQDs, and CQDs (from citric acid & urea) have been applied for a single wavelength detection of tartrazine by fluorescence quenching (75)(76)(77)(78), as depicted in Table 5. On the other hand, dual mode tartrazine detection with N,S-CQDs based fluorescent probe has been reported (79). ...
Carbon quantum dots (CQDs) belong to a remarkable category of nanocarbon materials with unique properties because of their nanoscale dimensions. These nanocarbons have earned significant attention because of their exceptional properties and advantages, making them versatile in a wide range of applications. This chapter delves into the fundamental principles underlying CQDs, along with their synthetic procedures and outstanding characteristics. These fundamental characteristics empower precise tuning of their optical and electronic properties, setting the stage for their diverse applications. Their phoยญtoยญluยญmiยญnesยญcenceโcombined with their biocompatibility, water solubility, and various surface functional groupsโposition CQDs as crucial components in the fields of nanotechnology, materials science, and medicine. As a result, this chapter highlights the broad spectrum of applications where CQDs have made significant contributions in the 21st century.
... "Recently, Carbon dots (CDs) based fluorescence sensors for food safety monitoring have attracted more and more attention due to excellent characteristics of CDs, such as excellent water solubility, low toxicity, tunable emission, and stability against photobleaching" [16][17][18]. A series of CDs were prepared for fluorescence sensing of TAR with good analytical performances [19][20][21][22][23][24][25][26][27][28]. However, hydrothermal procedure is still the most popular means of obtaining CDs with excellent optical properties, which is a time-consuming, energyconsuming preparation method, often accompanied by a longer dialysis purification process. ...
Rapid, green and high yield synthesis of nitrogen doped carbon dots(N-CDs) through exothermic decomposition reaction of H2O2 using grasshopper powder as precursor and polyethyleneimine (PEI) as a surface passivation reagent. Water-soluble fluorescent N-CDs can be obtained by reacting 5 minutes and purified N-CDs were obtained after an activated carbon adsorption separation procedure with a product yield of 53.3%. TEM, FT-IR, XPS, fluorescence and UV-vis spectra were used to investigate the morphology, elemental information and optical properties of N-CDs. The results indicated that the fluorescence emission of N-CDs is typical excitation wavelength dependent with a strongest emission peak at 417 nm under 330 nm excitation wavelength. There is a good linear response between the fluorescence intensity of N-CDs and temperature, which makes N-CDs a potential nanothermometer to monitor temperature. The great spectral overlap between the blue emission peak (417 nm) of N-CDs and the absorption peak (430 nm) of tartrazine (TAR) leads to an effectively fluorescence quenching phenomenon by TAR through inner filter effect (IFE) and the fluorescence quenching degree (lg(I0/I)) was linearly response to the TAR concentration in the range of 1-100 ยตM. The detection limit of developed method is 54.3 nM for TAR, and the relative standard deviation (RSD) is 1.14% (n=7, c=10 ฮผM). The N-CDs came from an exothermic reaction is a highly selective and sensitive fluorescent probe for TAR, and it was successfully applied to the determination of TAR in food samples with satisfactory results.
... CQDs were prepared using E. odoratum L. powder instead of biomass coffee grounds as carbon source [24,25]. The green synthesis process of CQDs is shown in Scheme 1. ...
Artificial sweetener needs to control the maximum dosage, such as aspartame, cyclamate, saccharin sodium, and sucralose, are mainly used in fruits, jams, beverages, desserts, and dairy products. In this research, a novel label-free fluorescent sensor based on carbon quantum dots (CQDs) were prepared by a one-step hydrothermal method using Eupatorium odoratum L., as a highly sensitive โturn-onโ-type fluorescent probe for the detection of artificial sweetener. They exhibit photoluminous emission at 444 nm under 370 nm excitation, with a quantum yield of 20.36%. Under optimal conditions, the standard curve of aspartame, neotame, and sucralose had good linearity in the concentration range of 0โ750 ยตmol/L, 0โ400 ยตmol/L, and 100โ800 ยตmol/L, respectively, and the linear correlation coefficients were 0.9913, 0.9978, and 0.9974. The CQDs were also shown to selectively react with aspartame, neotame, and sucralose, leading to fluorescence enhancing effect, and low limits of detection were 4.2383 ยตmol/L, 6.8834 ยตmol/L, and 7.6576 ยตmol/L, respectively, which were much lower than the limits of detection for aspartame (1.0194โ33.9789 mmol/L), neotame (26.4229โ792.6861 ยตmol/L), and sucralose (0.3772โ12.5745 mmol/L) in various foodstuffs as stipulated in GB 2760-2014. The results indicated our developed sensor based on E. odoratum L. CQDs has great application prospects for artificial sweeteners detection.
... A high concentration of tartrazine can cause anxiety, hyperactivity, depression, and asthma. DNA damage and interference with DNA synthesis can occur in case of exposure to excessive amounts of tartrazine (Li et al., 2022). Some studies have shown that carcinogenic effects can also occur, resulting in subcutaneous sarcoma, liver cancer, and intestinal cancer (Munoz-Flores et al., 2022). ...
... Previous studies have shown that excessive intake of artificial colors can affect children's mental development and even pose serious health risks. Li et al. [75] synthesized sulfurdoped CDs (S-CDs) from hollow rosemary and thiourea. The S-CQDs possessed excellent fluorescence properties, with a QY of 20.19%, and a selective reaction with lemon yellow, resulting in a fluorescence-quenching effect with a detection limit of 0.45 ฮผmol/L. ...
Food safety is connected to public health, making it crucial to protecting peopleโs health. Food analysis and detection can assure food quality and effectively reduce the entry of harmful foods into the market. Carbon dots (CDs) are an excellent choice for food analysis and detection attributable to their advantages of good optical properties, water solubility, high chemical stability, easy functionalization, excellent bleaching resistance, low toxicity, and good biocompatibility. This paper focuses on the optical properties, synthesis methods, and applications of CDs in food analysis and detection, including the recent advances in food nutritional composition analysis and food quality detection, such as food additives, heavy metal ions, foodborne pathogens, harmful organic pollutants, and pH value. Moreover, this review also discusses the potentially toxic effects, current challenges, and prospects of CDs in basic research and applications. We hope that this review can provide valuable information to lay a foundation for subsequent research on CDs and promote the exploration of CDs-based sensing for future food detection.
Food analysis is a key element in monitoring food quality for risk assessment concerning public health. Instead of using chemically prepared carbon sources for food analysis, eco-friendly and green technology based CQDs are in great demand due to their least toxicity. Carbon quantum dots (CQDs) represent an innovative group of fluorescent nanomaterials, possessing characteristics like photoluminescence, minimal toxicity, high water solubility, and a strong affinity for biocompatibility. Their versatility extends to various applications in fields like sensor technology, biomedicine, and photocatalysis, among other areas. This paper reviews the current challenges related to the use of food by-products as a source of carbon not only enhances the value of waste but also facilitates food safety detection. The integration of CQDs into food technology for food safety analysis shows a great impact on the economy and environment. Furthermore, the details of synthesis, toxicity, application, and characterization of CQDs were also described along with a brief conceptual overview. Particularly, the detection of food additives, food-borne pathogens, heavy metal ions, and pesticide residues was also elaborated. Furthermore, the advantages and the drawbacks are also discussed, with an emphasis on their future prospects in this emerging research field. This review concluded that the use of food residual components has been associated with several toxic effects and accumulation of these residues leads to many disorders like cancer, neurological disorder, reproductive disease, cardiovascular and arthritis. Moreover, the carbon source produced from food waste interacted with other functional groups like oxygen, hydrogen, and nitrogen through ฯ - ฯ * and n- ฯ* interactions. Overall, understanding the mechanism of fluorescence quenching of residual components is of great interest in the field of food detection, as it can provide insights into the design of cost-effective fluorescence probes with low toxicity.
The preparation of high-performance heteroatom-doped fluorescent carbon dots (CDs) from renewable biomass or biometabolites hold an extensive attention. Here, we report an excess sodium hydroxide (NaOH) assisted method by for the preparation of sulfur-doped carbon dots (S-CDs) at lower temperatures using thioctic acid (TA). Excessive NaOH can promote the thermal decomposition process of thioctic acid in the hydrothermal process, thereby realizing rapid reaction rate (critical time 1 h) and scalable synthesis at low temperature (120 ยฐC). The amount of NaOH and the reaction time were identified as the main factors affecting the synthesis, and the reaction of NaOH with disulfide bonds contributed the most to the generation of fluorescent S-CDs. This in-situ sulfur doping process resulted in excellent fluorescence properties, high relative quantum yield of 11.5%, low biotoxicity, good biocompatibility and excellent solubility, etc. In addition, this as-prepared fluorescent S-CDs showed excellent concentration dependence on ferric ions (Feยณโบ) and can achieve high-precision and selective detection. This work may provide a high-efficiency synthesis strategy for S-CDs for biological and detection applications.
