Vortex assisted-ionic liquid dispersive liquid-liquid microextraction and spectrophotometric determination of quercetin in tea, honey, fruit juice and wine samples after optimization based on response surface methodology

A comprehensive review of the current trends and recent advancements on the authenticity of honey

The authenticity of honey currently poses challenges to food quality control, thus requiring continuous modernization and improvement of related analytical methodologies. This review provides a comprehensively overview of honey authenticity challenges and related analytical methods. Firstly, direct and indirect methods of honey adulteration were described in detail, commenting the existing challenges in current detection methods and market supervision approaches. As an important part, the integrated metabolomic workflow involving sample processing procedures, instrumental analysis techniques, and chemometric tools in honey authenticity studies were discussed, with a focus on their advantages, disadvantages, and scopes. Among them, various improved microscale extraction methods, combined with hyphenated instrumental analysis techniques and chemometric data processing tools, have broad application potential in honey authenticity research. The future of honey authenticity determination will involve the use of simplified and portable methods, which will enable on-site rapid detection and transfer detection technologies from the laboratory to the industry.

An eco-friendly and sensitive deep eutectic solvent-based liquid-phase microextraction procedure for extraction preconcentration of Pb (II) ions

In recent years, interest in green solvents, which are environmentally friendly, easy to prepare and biodegradable, and in their applications in chemistry has considerably increased. In the current study, a new and easy deep eutectic solvent-based liquid-phase microextraction method compatible with green chemistry principles was developed for preconcentration of Pb (II) ions. The amount of Pb (II) ions was determined with graphite furnace atomic absorption spectrometry (GFAAS). Various analytical parameters such as deep eutectic solvent (DES) ratio and amount, ligand amount, pH, sample volume were optimized and the effects of potential matrix ions on the method were investigated. The preconcentration factor of the method was found to be 160, while the limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.071 µg L^-1 and 0.236 µg L^-1, respectively. The developed procedure was performed to determine Pb (II) ions in lake and river waters, and the accuracy of the procedure was determined with certified reference wastewater (SPS-WW1) analysis.

Smartphone imaging spectrometer for egg/meat freshness monitoring

Data transmission between spectroscopy equipment and mobile terminals is critical to realising hand-held field-level monitoring. Currently, on-the-go (OTG) communication technology is a convenient and efficient method of data transmission for mobile devices. However, few people associate spectroscopy equipment with smartphones through the OTG port. This study developed a portable imaging spectrometer with a spectral resolution of approximately 12 nm in the visible-near-infrared band (400-1000 nm). It can be connected to a smartphone through the USB-OTG port to process the spectral signal through the smartphone's system on a chip (SoC). It also displays real-time spectral images of the food samples through the smartphone's screen. Using a support vector machine (SVM) to classify the spectra of the various experimental samples (e.g. eggs and pork), the model prediction accuracy rate is approximately 90%. This further proves the reliability of the proposed smartphone imaging spectrometer for monitoring the freshness of food samples onsite.

An optimization approach for fast, simple and accurate determination of indigo-carmine in food samples

This study report optimization of vortex-assisted natural deep eutectic solvent based liquid-phase microextraction (VA-NADES-LPME) for determination of indigo-carmine in some food samples by UV-Visible spectrophotometer. To ensure efficient extraction, nine different NADES were prepared and tested for the extraction of indigo-carmine. In order to increase extraction efficiency of indigo-carmine, the effects of VA-NADES-LPME variables and their interactions were optimized with central composite design. The optimized method exhibited a linear range between 10 and 900 ng mL^-1. Limit of detection, limit of quantification and enrichment factor were determined as 3.3 ng mL^-1, 10 ng mL^-1 and 135-fold, respectively. The applicability of the optimized method was investigated in selected food samples using the matrix-matching calibration curve. Using optimised experimental conditions (pH of 3.2, 75 µL of NADES-4, 285 µL of THF, and 4 min vortexing), satisfactory recovery results were found in the range of 95.9-104.2% with 1.4-3.7% of relative standard deviation. Finally, the optimized method was economical, simple, green, requires less laborious sampling, and provides superior accuracy and precision in trace-level analysis.

Optimization of green and rapid analytical procedure for the extraction of patulin in fruit juice and dried fruit samples by air-assisted natural deep eutectic solvent-based solidified homogeneous liquid phase microextraction using experimental design and computational chemistry approach

In this paper, a green and inexpensive air-assisted natural deep eutectic solvent-based solidified homogeneous liquid phase microextraction procedure was optimized for extraction of patulin in fruit juice and dried fruit samples using experimental design prior to its spectrophotometric determination. Four different natural deep eutectic solvent were prepared and applied to ensure efficient, and selective extraction of patulin. The significant variables including Zn(II) amount, cooling time, pH and amount of natural deep eutectic solvent were optimized by using central composite design. Under optimized conditions, working range was 10-750 μg L^-1 with 0.9996 of correlation coefficient. Detection limit and preconcentration factor were 3.5 μg L^-1 and 150, respectively. The repeatability and reproducibility precision were in the range of 3.2-4.6% and 4.3-5.6% respectively. Recoveries ranging from 94% to 104% proved the accuracy of the method. The optimized method was successfully applied to the extraction and identification of patulin in the selected samples.

Analysis of Zinc and Chromium in Grain Samples Using Ionic Liquid-Based Ultrasound-Assisted Microextraction Followed by Flame-AAS After Microwave Digestion

A simple, rapid and eco-friendly microextraction method was developed for the determination and preconcentration of zinc (Zn) and chromium (Cr) from grain products by ultrasonic-assisted ionic liquid dispersive liquid-liquid microextraction (UA-IL-DLLME) combined with flame atomic absorption spectrometry (FAAS). Quercetin (2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one dihydrate) was used for the complexation of Zn(II) and Cr(III) ions at different pHs. The 1-hexyl-3-methylimidazolium bis[(trifluoromethyl) sulfonyl]imide ([Hmim][NTf2] and acetonitrile were used as extraction solvent and dispersive solvent, respectively. To provide quantitative extraction of analytes, important experimental variables such as pH of sample solution, temperature, ultrasonic time, amount of chelating agent, amount of ionic liquid, type and amount of dispersive solvent, and interference effect were extensively studied and optimized. The detection limits and operating ranges for Zn(II) and Cr(III) using the optimized conditions were 7.5, 25-450 and 2.4, 8-300 μg L^-1, respectively. For the validation of the proposed method, the certified reference material was tested using the standard addition method. After microwave digestion analysis of grain products, relative standard deviations (RSDs%) and recoveries were ranged from 1.2 to 2.3% and from 91.2 to 103.7%, respectively. The UA-IL-DLLME method has been successfully applied for the determination of Zn and Cr in grain samples (chickpea, broad bean, pea, beans, and wheat).