Development of a highly sensitive fluorescence method for tartrazine determination in food matrices based on carbon dots

A comprehensive exploration of tartrazine detection in food products: Leveraging fluorescence nanomaterials and electrochemical sensors: Recent progress and future trends

Azo dyes are widely used as food coloring agents because of their affordability and stability. Examples include brilliant blue, carmoisine, sunset yellow, allura red, and tartrazine (Tar), etc. Notably, Tar is often utilized in hazardous food goods. They are frequently flavoured and combined with food items, raising the likelihood and danger of exposure. Therefore, detecting Tar in food is crucial to prevent health risks. Fluorescence nanomaterials and electrochemical sensors, known for their high sensitivity, affordability, simplicity, and speed, have been widely adopted by researchers for Tar detection. This comprehensive paper delves into the detection of Tar in food products. It extensively covers the utilization of advanced carbon-based nanomaterials, including CDs, doped CDs, and functionalized CDs, for sensitive Tar detection. Additionally, the paper explores the application of electrochemical sensors. The paper concludes by addressing current challenges and prospects, emphasizing efforts to enhance sensitivity, and selectivity for improved food safety.

Green-emitting carbon dots as a "turn on" fluorescence bio-probe for highly sensitive and selective detection of lipase in human serum

Enzyme activity assays play a crucial role in numerous fields, including biotechnology, the food industry, and clinical diagnostics. Lipases are particularly important enzymes due to their widespread use in lipid metabolism and esterification reactions. Here, we present a pioneering method for the sensitive and selective determination of lipase activity using green carbon dots (G-CDs) for first time. G-CDs are a fascinating class of carbon nanomaterials with unique optical properties and biocompatibility, making them ideal candidates for enzyme activity assays. This approach eliminates the need for traditional fluorophores or chromogenic substrates, reducing costs, fast response time (1 min), and environmental impact with a quantum yield (QY) of 7.42%. As designed, the G-CDs fluorescent probe turn-on demonstrated a reliable linear detection range from 0 to 9 mg/mL under ideal conditions, with detection limit of 0.01 mg/mL and limit of quantification (LOQ) of 0.045 mg/mL, respectively. Furthermore, the G-CDs system was thoroughly evaluated in human serum samples, showing recoveries ranging from 100.0 to 105.0%. These findings highlight the promising applicability of the G-CDs probe for lipase detection, yielding highly favorable results.

A fluorescent sensor based on sulfur nanodots encapsulated into zeolitic imidazolate framework-8 for ultrasensitive detection of tartrazine

A new composite material (SDs@ZIF-8) was synthesized by integrating sulfur nanodots (SDs) into metal-organic frameworks (ZIF-8) through a facile one-step self-assembly strategy. The obtained SDs@ZIF-8 has not only the high adsorption performance of ZIF-8 but also the superior fluorescence characteristics of SDs. The composite featured good dispersibility, stable structure as well as excellent fluorescence in water solution, and can be used as an ideal fluorescent sensor for tartrazine detection. Due to the high specific surface area and adsorption performance of ZIF-8, the prepared composite material can significantly enrich tartrazine, further enhancing the sensitivity of analysis. The fluorescence of SDs @ZIF-8 composite can be effectively quenched by tartrazine through the inner filter effect. The sensing technique exhibited exceptional sensitivity, as evidenced by its impressive detection limit of 6.5 nM across a broad linear range spanning from 0.02 to 90 μM. In addition to its high sensitivity, the technique displayed rapid response times and excellent selectivity. Moreover, the fluorescent sensing technology we developed has been employed successfully for the detection of tartrazine in real samples, which is expected to promote the development of the food safety industry.

Using a Smartphone-Based Colorimetric Device with Molecularly Imprinted Polymer for the Quantification of Tartrazine in Soda Drinks

The present study reports the development and application of a rapid, low-cost in-situ method for the quantification of tartrazine in carbonated beverages using a smartphone-based colorimetric device with molecularly imprinted polymer (MIP). The MIP was synthesized using the free radical precipitation method with acrylamide (AC) as the functional monomer, N,N'-methylenebisacrylamide (NMBA) as the cross linker, and potassium persulfate (KPS) as radical initiator. The smartphone (RadesPhone)-operated rapid analysis device proposed in this study has dimensions of 10 × 10 × 15 cm and is illuminated internally by light emitting diode (LED) lights with intensity of 170 lux. The analytical methodology involved the use of a smartphone camera to capture images of MIP at various tartrazine concentrations, and the subsequent application of the Image-J software to calculate the red, green, blue (RGB) color values and hue, saturation, value (HSV) values from these images. A multivariate calibration analysis of tartrazine in the range of 0 to 30 mg/L was performed, and the optimum working range was determined to be 0 to 20 mg/L using five principal components and a limit of detection (LOD) of 1.2 mg/L was obtained. Repeatability analysis of tartrazine solutions with concentrations of 4, 8, and 15 mg/L (n = 10) showed a coefficient of variation (% RSD) of less than 6%. The proposed technique was applied to the analysis of five Peruvian soda drinks and the results were compared with the UHPLC reference method. The proposed technique showed a relative error between 6% and 16% and % RSD lower than 6.3%. The results of this study demonstrate that the smartphone-based device is a suitable analytical tool that offers an on-site, cost-effective, and rapid alternative for the quantification of tartrazine in soda drinks. This color analysis device can be used in other molecularly imprinted polymer systems and offers a wide range of possibilities for the detection and quantification of compounds in various industrial and environmental matrices that generate a color change in the MIP matrix.

Progress in Fluorescence Biosensing and Food Safety towards Point-of-Detection (PoD) System

The detection of pathogens in food substances is of crucial concern for public health and for the safety of the natural environment. Nanomaterials, with their high sensitivity and selectivity have an edge over conventional organic dyes in fluorescent-based detection methods. Advances in microfluidic technology in biosensors have taken place to meet the user criteria of sensitive, inexpensive, user-friendly, and quick detection. In this review, we have summarized the use of fluorescence-based nanomaterials and the latest research approaches towards integrated biosensors, including microsystems containing fluorescence-based detection, various model systems with nano materials, DNA probes, and antibodies. Paper-based lateral-flow test strips and microchips as well as the most-used trapping components are also reviewed, and the possibility of their performance in portable devices evaluated. We also present a current market-available portable system which was developed for food screening and highlight the future direction for the development of fluorescence-based systems for on-site detection and stratification of common foodborne pathogens.

Facile hydrothermal synthesis and purification of fluorescent carbon dots for food colorant tartrazine detection based on a dual-mode nanosensor

Colorant tartrazine is widely used in the food industry, but its long-term and excessive consumption is harmful to human health. Therefore, it is necessary to establish a sensitive detection method for tartrazine. Blue fluorescent carbon dots with L-arginine and o-phenylenediamine as precursors, namely L-Arg/oPD-CDs, were prepared via the hydrothermal method. Then, L-Arg/oPD-CDs were further purified by dialysis, thin layer chromatography and column chromatography. A dual-mode nanosensor based on fluorescent and UV absorption was successfully developed. Excellent linear ranges of 0-5 μM and 10-50 μM were obtained with a low detection limit of 42.3 nM based on fluorescence. A good linear range of 0-50 μM was obtained with a low detection limit of 130.15 nM based on UV absorption. The quenching mechanism of tartrazine towards L-Arg/oPD-CDs fluorescence was the inner filter effect. In addition, a dual-mode nanosensor was used for tartrazine determination in millet, maize flour, carbonated drink, and sugar samples. This study provides new insight into the detection of tartrazine by applying a dual-mode nanosensor.