Foodstuff Samples Research Articles

Toxic Metal Concentrations and Exposure Risks Associated with Surface Water, Seafood (Clarias gariepinus, Oreochromis niloticus, Cottus gobio) and Vegetable (Telfairia occidentalis) from Elebele River, Nigeria

Human exposure to elevated levels of environmental contaminants is an important concern of health toxicology. This study assessed the toxicity level of toxic metals including Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Lead (Pb) and Nickel (Ni) in samples of water, seafood (Clarias gariepinus, Oreochromis niloticus, Cottus gobio) and vegetable (Telfairia occidentalis) from the adjacent area of Elebele River, Nigeria, bioconcentration and toxic metal exposure posed to communities consuming these foodstuffs. The following indices: single-factor index and the comprehensive pollution index, metal pollution index, estimated daily and weekly intakes, hazard index and lifetime cancer risk were applied. Samples of water, seafood and vegetable were analysed using Atomic Absorption Spectrophotometer. The results showed that the concentrations of metals except for Cd in water samples were higher than the permissible limits by international organisations. Results also revealed that the concentrations of metals in foodstuff samples were within limits. Furthermore, the values of estimated weekly intakes calculated were lower than the limits of provisional tolerable weekly intakes established by the Food and Agriculture Organization and World Health Organization. This suggests no health risks and is consistent with the HI results. However, As was a major contributor (96.9%) to health risks associated with the ingestion of water. Lifelong consumption of T. occidentalis might be hazardous in the study locality. The carcinogenic risk was > 1 × 10‒4 for As and Ni. Therefore, to reduce the health risk and the extent of metal contamination, steps must be taken for the efficient removal of metals from the water body.

A sensitive electrochemical biosensor for quinolones detection based on Cu2+-modulated signal amplification

In this work, a sensitive electrochemical biosensor is developed for the detection of quinolones based on Cu2+-modulated signal amplification. In the presence of target quinolones, the formation of quinolones-Cu2+ complex inhibits the activity of Cu2+-specific DNAzyme. As a result, the intact substrate DNA probe of Cu2+-specific DNAzyme is reserved to trigger the hybridization chain reaction, forming long dsDNA nanowires on the surface of the electrode and finally generating a significant amplification of electrochemical signal positively correlated with the concentration of target quinolones. Benefiting from the Cu2+-modulated signal amplification, a good linear relationship between the electrochemical signal and the logarithm of ciprofloxacin concentration can be obtained in the range from 0.1 ng mL−1 to 200 ng mL−1, and the limit of detection is low to 0.052 ng mL−1. With the advantages of simple operation, high sensitivity and specificity, the electrochemical biosensor has been utilized to assay ciprofloxacin in real foodstuff samples, exhibiting satisfactory analytical performance and showing latent practicability in food safety detection.

Electrochemical-Based Sensing Platforms for Detection of Glucose and H2O2 by Porous Metal–Organic Frameworks: A Review of Status and Prospects

Establishing enzyme-free sensing assays with great selectivity and sensitivity for glucose and H2O2 detection has been highly required in biological science. In particular, the exploitation of nanomaterials by using noble metals of high conductivity and surface area has been widely investigated to act as selective catalytic agents for molecular recognition in sensing platforms. Several approaches for a straightforward, speedy, selective, and sensitive recognition of glucose and H2O2 were requested. This paper reviews the current progress in electrochemical detection using metal-organic frameworks (MOFs) for H2O2 and glucose recognition. We have reviewed the latest electrochemical sensing assays for in-place detection with priorities including straightforward procedure and manipulation, high sensitivity, varied linear range, and economic prospects. The mentioned sensing assays apply electrochemical systems through a rapid detection time that enables real-time recognition. In profitable fields, the obstacles that have been associated with sample preparation and tool expense can be solved by applying these sensing means. Some parameters, including the impedance, intensity, and potential difference measurement methods have permitted low limit of detections (LODs) and noticeable durations in agricultural, water, and foodstuff samples with high levels of glucose and H2O2.

A homogeneous liquid–liquid microextraction based on temperature-controlled ionic liquid for the accurate and selective determination at low levels of zineb residues in foodstuff by using experimental design

ABSTRACT A simple and homogeneous green liquid–liquid microextraction based on temperature-controlled ionic liquid (IL) process was developed for the selective extraction and spectrophotometric analysis of zinc (II) ethylenebis (dithiocarbamate) (zineb) from different foodstuff samples including rice, wheat, corn, oat, cabbage, potato, tomato and grain. The effect of various parameters like pH, IL dose, temperature, ultrasound time and foreign ions were studied. The proposed method exhibited good precision and accuracy for extraction recovery of zineb. The samples were spiked with 50 and 150 µg of zineb and checked its effects on the recovery of zineb. The LOD 9.1 ng mL−1, LOQ 30 ng mL−1, linear range 30–600 ng mL−1, enhancement factor 152 and RSD % values were found 3.2%. The multivariate statistical analysis was also carried out to interpret the data. The factorial design was used to examine the impacts of variables on extraction recovery of zineb from foodstuff.

Improved procedure for square-wave voltammetric sensing of fenhexamid residues on blueberries peel surface at the anodically pretreated boron-doped diamond electrode

BackgroundFungicide fenhexamid (FH) has a high residual concentration on fruits and vegetables, thus, it is of high importance to monitor the level of FH residues on foodstuff samples. So far, the assay of FH residues in selected foodstuff samples has been conducted by electroanalytical methods on sp2 carbon-based electrodes that are well-known to be susceptible to severe fouling of the electrodes surfaces during electrochemical measurements. As an alternative, sp3 carbon-based electrode such as boron-doped diamond (BDD) can be used in the analysis of FH residues retained on the peel surface of foodstuff (blueberries) sample. ResultsIn situ anodic pretreatment of the BDDE surface was found to be the most successful strategy to remediate the passivated BDDE surface by FH oxidation (by)products, and the best validation parameters, i.e., the widest linear range (3.0–100.0 μmol L−1), the highest sensitivity (0.0265 μA L μmol−1) and the lowest limit of detection (0.821 μmol L−1), were achieved on the anodically pretreated BDDE (APT–BDDE) in a Britton-Robinson buffer, pH 2.0, using square-wave voltammetry (SWV). The assay of FH residues retained on blueberries peel surface was performed on the APT–BDDE using SWV, and the obtained concentration of FH residues of 6.152 μmol L−1 (1.859 mg kg−1) was found to be below the maximum residue value fixed for blueberries by the European Union regulations (20 mg kg−1). Significance and noveltyIn this work, a protocol based on a very easy and fast foodstuff sample preparation procedure combined with the straightforward pretreatment approach of the BDDE surface was elaborated for the first time for the monitoring of the level of FH residues retained on the peel surface of blueberries samples. The presented reliable, cost-effective, and easy-to-use protocol could find its application as a rapid screening method for the control of food safety.

Aflatoxin Susceptible Food Consumption Frequency, Prevalence, and Levels in Household Foodstuffs in Southwestern Uganda

Contamination of household foodstuffs by aflatoxins has been associated with many illnesses, especially hepatocellular cancer and malnutrition. Aflatoxins are toxins produced by fungi, especially Aspergillus flavus and Aspergillus parasiticus, usually found in food. Literature concerning the S.W. Ugandan foods that are the main aflatoxicosis route and therefore need most aflatoxin preventive measure is scanty. The current study determined the aflatoxin-susceptible food consumption frequency, prevalence, and levels of aflatoxins in selected foodstuffs in households in S.W. Uganda to establish the main food route of aflatoxicosis. Following a food frequency questionnaire, flour samples of common foodstuffs, namely, groundnuts, maize, millet, and sorghum, were randomly picked from seven districts of Southwest Uganda and analyzed for the presence and levels of aflatoxins using competitive ELISA. On average, maize and groundnut were found to be the most frequently consumed foods (seven times a week) by every family. Groundnuts had the highest mean aflatoxin level (96.5 ± 13.37 μg/kg), ranging from 6.2 to 297.3 μg/kg. Over 90% of the groundnut samples had mean aflatoxin levels greater than 10 μg/kg, the East African regulatory limit. Maize flour had a mean aflatoxin level of 34.1 ± 14.1 μg/kg, with one sample registering 336.5 μg/kg. This study found that groundnuts were the main food-route for aflatoxicosis followed by maize flour. In addition, the study re-affirmed the high prevalence and levels of aflatoxins in common food stuff in households in S.W. Uganda reported by previous studies. This study recommends further studies to elucidate its association with the observed recent increase in diseases like hepatocellular cancer and malnutrition in the region.

Assessment of Aflatoxin Contamination in Maize and Groundnuts during Storage in Giwa Community, Kaduna State Nigeria

Contamination of food and feed by aflatoxins has become a worldwide cause of public health concern due to its significant impact on human health and crop market value. The present study aimed to assess the aflatoxin contents of maize and groundnut from stores and warehouses in the Giwa community, Kaduna State, Nigeria. A total of ninety (90) grain samples of maize and groundnut were collected between October to December 2020 and analyzed for total aflatoxins using Enzyme-Linked Immuno Sorbent Assay (ELISA). Eighty-four 84(93.3%) of the samples had detectable aflatoxin levels (0.2-9.8ppb), while six 6(6.7%) had none. There was no significant difference (P>0.05) in the mean total aflatoxin content of the grains from stores, warehouses and household foodstuff samples. This could be attributed to agricultural practices and low temperature and humidity storage conditions, which were the same for all the stored grains. Overall, aflatoxin concentrations of the grain samples were within the acceptable limit (10ppb for maize and 15ppb for groundnut) for food safety set by NAFDAC. However, there could be further contamination during storage, particularly when temperature rises and humidity increases. Hence, improved storage conditions and monitoring of grain before sale are recommended to avoid contamination during storage and to ensure a healthy and safe food supply along the trade chain and to the consumers.

Radioactivity assessment of selected samples of foodstuffs in the local market

The research aims to evaluate the radioactivity of samples of foodstuffs Consumables in the local markets thirteen items were selected which are rice, tea, drinking water, lentils, chickpeas, flour, red bean, crushed chickpeas and milk powder where the concentrations of the specific activity of the chains of uranium (238U), thorium (232Th) and potassium (40K) were measured using a gamma ray spectra analysis system with a high purity germanium (HPGe) detector using a program (Genie 2000) developed, where the results showed that potassium concentrations are clear, and the measurements showed low values ​​for the concentrations of uranium and other natural isotopes, and no values ​​were indicated for the presence of the industrial isotope cesium (137CS), where it was found that the specific activity, which is measured by the unit (Bq/kg) of potassium ((40K) in The studied samples ranged from (BDL -397.977 ± 25.894 ) with a rate of (143.559 ± 10.616), and for uranium 238U (BLD -7.114 ± 0.877) with a rate of (1.904 ± 0.214) and thorium (232Th) B.L.D (Below the detection level ) the radium equivalent Raeq, which is measured by the unit (Bq/kg) whose value ranges from (BDL -37.758) and the rate of (12.959), and the internal hazard index Hin, which is measured by the unit (Bq/kg) (BDL -0.121) was calculated and with rate (0.040), and the annual effective dose of potassium (40K) measured in μSv/y whose values ​​range (BDL -1357.102 ) and an average (489,539) as a result of eating these foodstuffs that were within the permissible level per person in the general public during a year and according to the recommendations of the committee UNSCEAR, where the permissible exposure per person is (1mSv/y).

Comprehensive analysis of a decade of cumulative radiocesium testing data for foodstuffs throughout Japan after the 2011 Fukushima Daiichi Nuclear Power Plant accident.

The unexpected accident at the Fukushima Daiichi Nuclear Power Station in Japan, which occurred on March 11th, 2011, after the Great East Japan Earthquake and tsunami struck the north-eastern coast of Japan, released radionuclides into the environment. Today, because of the amounts of radionuclides released and their relatively long half-life, the levels of radiocesium contaminating foodstuffs remain a significant food safety concern. Foodstuffs in Japan have been sampled and monitored for 134,137Cs since the accident. More than 2.5 million samples of foodstuffs have been examined with the results reported monthly during each Japanese fiscal year (FY, from April 1st to March 31st) from 2012 to 2021. A total of 5,695 samples of foodstuffs within the “general foodstuffs” category collected during this whole period and 13 foodstuffs within the “drinking water including soft drinks containing tea as a raw material” category sampled in FY 2012 were found to exceed the Japanese maximum permitted level (JML) set at 100 and 10 Bq/kg, respectively. No samples from the “milk and infant foodstuffs” category exceeded the JML (50 Bq/kg). The annual proportions of foodstuffs exceeding the JML in the “general foodstuffs” category varied between 0.37% and 2.57%, and were highest in FY 2012. The 134,137Cs concentration for more than 99% of the foodstuffs monitored and reported has been low and not exceeding the JML in recent years, except for those foodstuffs that are difficult to cultivate, feed or manage, such as wild mushrooms, plants, animals and fish. The monitoring data for foodstuffs show the current status of food safety risks from 134,137Cs contamination, particularly for cultured and aquaculture foodstuffs on the market in Japan.

Aflatoxins contents determination in some foodstuffs in Burkina Faso and human health risk assessment.

Aflatoxins are produced by fungi of the genus Aspergillus that colonize many foodstuffs during agricultural production, harvesting, transportation, storage, and food processing. In view of these aflatoxins toxicity to humans, their presence in foods such as cereals and oilseeds constitutes a major challenge for global food security, health and nutrition. This study was therefore initiated to assess the level of aflatoxin contamination of various foodstuffs sold in urban and semi-urban markets in Burkina Faso, and to evaluate the carcinogenic risk which the consuming population is exposed to. Two hundred and twelve foodstuff samples were collected in two large cities (Ouagadougou and Bobo Dioulasso) and three semi urban localities (Cinkansé, Dakola and Niangoloko). Aflatoxins contents in foodstuffs were determined by immunoaffinity chromatography and human health risk assessment was performed by using the Monte Carlo algorithm. The aflatoxins contents determination showed that 41.50% of studied samples were contaminated with concentrations up to 182.28 μg/kg for AFB1 in peanuts. Chronic Daily Intake, calculated based on the consumption patterns assumed in this study, was estimated to be higher in large cities (CDI = 33.68 μg/kg bw in Ouagadougou and 10.18 μg/kg bw in Bobo Dioulasso) than in semi urban localities (CDI = 4.29 μg/kg bw in Cinkansé, CDI = 0.39 μg/kg bw in Dakola and CDI = 0.18 μg/kg bw in Niangoloko). The MOE determination showed that the sorghum meal and whole grain maize consumption was associated to the carcinogenic risk for public health in large cities (the percentile 95 of MOE = 3316 for rice, 4511 for peanuts, 3334 for sorghum meal and 4530 for whole grain maize). In semi urban localities, no carcinogenic risk was observed to public health. These results should inspire the country's sanitary and agricultural authorities to undertake actions to fight against the agricultural food products contamination by aflatoxins in order to safeguard the population's health.

An intrinsic dual-emitting fluorescence sensing toward tetracycline with self-calibration model based on luminescent lanthanide-functionalized metal-organic frameworks

A novel ratiometric fluorescence sensor based on lanthanide-functionalized metal-organic frameworks (Ag+/Eu3+@UiO-66(COOH)2, AEUC) with intrinsic dual-emitting bands was fabricated to determine tetracycline (TC) residues by exploiting (UiO-66-(COOH)2, UC) as reference units, Eu3+as recognition units and Ag+ as fluorescence enhancer. Benefiting from specific binding sites and functional adsorbent channels of AEUC, efficient capture and specific recognize toward TC could be achieved, remarkably enhancing the reliability. The synergistic effect of inner filter effect (IFE) and photoinduced electron transfer (PET) process between TC and AEUC was verified, enabling the detection limit and quantification limit of established strategy reaching as 12.8 nmol/L and 38.6 nmol/L and conspicuous fluorescence color gradation from red to blue. Given its portability, point-of-care sensing platform and nanoprobe-immobilized test-paper-based measurement allowing for on-site qualitative identification and semi-quantitative assay of TC was devised for sensing visualization and has been successfully applied in foodstuff samples, providing prospect in the field of smart devices for visual monitoring of TC.

Comparative study of neonicotinoid insecticides (NNIs) and NNI-Related substances (r-NNIs) in foodstuffs and indoor dust.

Comparative studies of neonicotinoid insecticides (NNIs) and NNI-related substances (r-NNIs) in foodstuffs and indoor dust are rare. Herein, we investigated the feature fragmentations of nine NNIs in high-energy collision dissociation cells via high-resolution orbitrap mass spectrometry and observed that NNIs can consistently generate several feature fragments (e.g., C6H5NCl+, C4H3NSCl+, and C6H5NF3+). Consequently, NNIs and r-NNIs were comprehensively (targeted, suspect, and feature fragment-dependent) detected in 107 foodstuff and 49 indoor dust samples collected from Nanjing City (eastern China). We fully or tentatively identified 9 target NNIs and 5 r-NNIs in these samples. NNIs and r-NNIs were detected in 93.5% of the analyzed foodstuff samples, and high concentrations were detected in vegetables (mean: 409ng/g wet weight [ww]) and fruits (127ng/g ww). Regarding indoor dust, imidacloprid and acetamiprid exhibited extremely high detection frequencies and contamination levels, and the highest mean concentrations of NNIs and r-NNIs were detected in dormitory samples. Based on the NNI and r-NNI concentrations in the analyzed samples, the mean estimated daily intake values for Chinese adults and children via dietary intake and dust ingestion were 2080-8190ng/kg bw/day and 378-2680pg/kg bw/day, respectively.

Spectrophotometric determination of chlorpyrifos in foodstuff after pipette-tip micro solid extraction by modified carbon nanotube

In this study, polypropylene-based carbon nanotubes (CNTs/PPy) were prepared and employed as a novel sorbent for pipette tip micro-solid phase extraction of chlorpyrifos from foodstuff samples followed by its spectrophotometric determination. Various parameters that can effect on analytical extraction (type and volume of eluent, mass of CNTs/PPy, pH and volume of sample solution, and extraction and elution cycles number) were studied and optimized by using one-variable-at-a-time procedure, central composite design (CCD) and Box-Behnken design (BBD) and results were compared. Among them, BBD showed the best performance. For BBD and CCD, experimental design was employed with four variables in three levels. The linear range under optimum conditions for the analyte was 1–1000 µg L−1 by a limit of detection of 0.17 µg L−1. The suggested protocol has been successfully employed for the determination of chlorpyrifos in tomato, cucumber and fish samples.

Effective solid-phase extraction of chlorophenols with covalent organic framework material as adsorbent

In this work, a porous extended network covalent organic framework designated as TP-NDA-COF was synthesized by the reaction of 2,4,6-trihydroxy-benzene-1,3,5-tricarbaldehyde (TP) and 1,5-naphthalenediamine (NDA). The structure and morphology of the TP-NDA-COF was characterized by means of Fourier transform infrared spectra (FT-IR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscope (SEM). The TP-NDA-COF was applied as a solid-phase extraction adsorbent for the extraction of some chlorophenols from water and lemon black tea beverage samples prior to high performance liquid chromatography-UV detection. The main experimental parameters that affect the extraction efficiency including the type and volume of eluent, sample solution volume, sample loading rate and sample solution pH were investigated. Under the optimal conditions, the calibration curves were linear in the range of 0.30–60.0 ng mL−1 with the determination coefficients (R2) of 0.9996–0.9998 for water samples and in the range of 0.60–60.0 ng mL−1 with the R2 values from 0.9990 to 0.9996 for beverage samples. At the signal to noise ratio of 3 (S/N = 3), the method LODs for the analytes were 0.10–0.15 ng mL−1 for water samples and 0.20–0.50 ng mL−1 for lemon black tea beverage, respectively. Good repeatability was achieved with the relative standard deviations of less than 7%. The results showed that the SPE-HPLC method can be used for the determination of chlorophenols in environmental water and foodstuffs samples.

Recyclable flexible upconversion-luminescence sensing platform for quantifying sulfite based on inner filter effect

The widespread applications of sulfur dioxide and its derivatives is a double-edged sword in terms of ensuring environmental and food safety. In this work, a recyclable flexible upconversion-luminescence sensor was developed for the determination of sulfite in environmental and foodstuff samples. The upconversion nanoparticles (UCNPs) were uniformly doped with polydimethylsiloxane (PDMS) prepolymer and moulded to prepare a flexible upconversion-luminescence substrate, which was further modified with pararosaniline (PRA) dye based on the typical carbodiimide coupling procedure. The principle of the work was based on the inner filter effect (IFE) mechanism between PRA dye and UCNPs. In the presence of target sulfite ions, it selectively binds to PRA moieties fixed on the surface of the flexible sensor, resulting in its bleaching and restoration of the upconversion fluorescence. Under the optimized conditions, a linear response for sulfite concentration in the range of 10–100 nM was obtained. The limit of detection was calculated as 2.24 nM, and the proposed sensor was successfully regenerated and recycled six times. The method was applied in real rainwater samples with spiked recoveries in the range of 94.85%–99.39%, and the coefficient of variation ranged from 1.65% to 4.93%. Hence, the proposed flexible upconversion-luminescence sensor held the attractive potential for efficient sulfite determination in real environmental and food samples.

Application electrochemical sensor based on nanosheets G-C3N4/CPE by square-wave anodic stripping voltammetric for measure amounts of toxic tartrazine color residual in different drink and foodstuffs

The present work describes a method (SWASV) techniques for measure of tartrazine color a harmful compound present in real samples, and the extremely harmful to humans and animals even at low concentrations using G-C3N4 nanosheets sensor. Here, we report the use of an electrochemical approach for analytical determination of toxic tartrazine that takes 150 s. The calibration curve was linear in range of the (0.02–18.0 µmol L−1). The current response was linearly proportional to the tartrazine concentration with a R 2∼ 0.999. We demonstrated a sensitivity a limit of detection of (0.022 µmol L−1). Finally, sensor nanosheets G-C3N4/CPE introduced to measure toxic tartrazine in different drink and foodstuff samples was used and the chemical nanosheets G-C3N4/CPE sensor made it possible as an excellent sensor with reproducibility for determination other samples.

IDENTIFICATION OF ORGANIC COMPOUNDS AS CARBOHYDRATES AND CHEMICALS CONTAINED IN THEM

This study aims to observe the structure of some carbohydrates through their reaction properties with multiple test reagents and know and understand various carbohydrate tests. Research methods used Research methods used are analytics with experimental design (pre experimental), Object of research is milk, honey, sago, flour and amylum. Then to five samples each added with NaOH, HCL, Aquades to find out if the five samples contain carbohirat or not.
 The results showed that Carbohydrates are nutrients in the form of organic compounds consisting of carbon atoms, hydrogen, and oxygen used as energy-forming materials. In this carbohydrate study, an iodine test was conducted to prove the presence of carbohydrate content in 5 samples of foodstuffs, namely iodine test on sago, honey, amylum, flour and milk. In the first experiment milk added NaOH, HCL, aquades the result did not change the layer and color, then the second experiment on honey in the pond NaOH, HCL, Aquades the result is two layers and the change of color to blackish yellow, then the third experiment on flour added NaOH, HCL, Aquades the result there are two layers and discoloration in each organic compound mixed in the sample, next experiment to the fourth on sago added NaOH, HCL,

Determination of profenofos in seawater and foodstuff samples after its molecularly imprinted polymer pipette-tip micro solid phase extraction optimized by response surface methodology

BackgroundIn this research, a molecularly imprinted polymer (MIP) was synthesized and employed as a sorbent for pipette-tip micro solid phase extraction of profenofos insecticide in seawater, rice, and fish samples. The instrument employed for quantitation was spectrophotometry.ResultsVarious factors affecting the microextraction protocol, including type and volume of the elution solvent, weight of MIP, pH and volume of sample solution, and number of cycles of loading and desorption were considered and optimized using one-factor-at-a-time, central composite design and Box-Behnken design. Factors optimized at: pH 4.0, amount of sorbent 2.5 mg, volume of methanol:acetic (9:1) acid as eluent 250 µL, both the number of extraction and elution cycles 5, and volume of sample 8.0 mL. At optimized conditions, an enrichment factor of 31 was achieved and the linearity range of the method was between 1.0 and 1000.0 µg/L. A good detection limit of 0.33 µg/L with a reproducibility better than 5.6% (as RSD) was observed.ConclusionThe technique showed good analytical features for determination of profenofos in seawater, rice, and fish samples. Simplicity of operation of spectrophotometry and lack of using expensive HPLC grade solvents are other points of strengths of this method. The total analysis time was about 10 min, which is far less than techniques such as HPLC. Comparison between optimization with central composite design and Box–Behnken design showed better performance of the former.

Construction of a Turn-off-on Fluorescent System Based On Aggregation Induced Emission of Acetaldehyde Using Carbonized Polymer dots and Tb3.

It was the first time to report the aggregation induced emission (AIE) of acetaldehyde (AA) on the surface of carbonized polymer dots (CPDs) with the auxiliary of Tb3+. Based on the AIE of AA, a turn-off-on fluorescence method was established for AA detection using the porous CPDs-Tb3+ system. The one-pot hydrothermal method was used to obtain CPDs, using milk and polyethyleneimine (PEI) as precursors. In the presence of Tb3+, CPDs aggregated immediately and even forming precipitate, and the fluorescence intensity decreased obviously. AA can effectively embed on the surface of CPDs-Tb3+ due to the porous structure. AA displayed obviously blue fluorescence with excitation wavelength at 370nm (emission peak at 460nm), while there was no fluorescence peak when excited at 460nm. In the CPDs-Tb3+ solution, AA exhibits obvious fluorescence enhancement effect (λex 460nm, λem 545nm). And then, AA can be determined by the turn-off-on system based on the linear relationship between fluorescence enhancement and the concentration of AA ranging from 0.04mM to 42.48mM. The limit of detection (LOD) was 0.02mM. The turn-off-on system was successfully applied to determine AA in wine samples. The strategy may be exploited to monitor AA in more drinking or foodstuff samples.

Comprehensively screening of citric acid ester (CAE) plasticizers in Chinese foodstuffs, and the food-based assessment of human exposure risk of CAEs

An increasing number of studies on the toxicities of citric acid esters (CAEs)—a class of so-called “safe” alternative plasticizers—have highlighted the urgent need to understand their contamination profiles in foodstuffs and the corresponding potential risks to human health. This study determined the concentrations of 8 target CAEs in 105 foodstuff samples, grouped into 6 food categories, collected from Nanjing City, China, in 2020. All eight CAEs were detected in at least one of the analyzed samples and had detection frequencies (DFs) of 5–47%. The DFs and distribution profiles of the target CAEs varied among different food categories; for example, cereals had the highest DF (92%), while meat/fish contained the highest mean total concentration of CAEs (8.35 ng/g wet weight (ww)). Among the target CAEs, acetyl tributyl citrate (ATBC) had the highest DF (47%), and tributyl citrate (TBC) exhibited the highest mean concentration (1.24 ng/g ww). Based on the food ingestion route, the estimated total daily intake (EDI) values of the target CAEs for adults under average- and high-exposure scenarios were 38.3 ng/kg of body weight (bw) and 111 ng/kg bw, respectively, which were attributed to the high percentage contributions of TBC (50.6%) and ATBC (23.7%). In addition, a suspect and characteristic fragment-dependent screening strategy was applied to the foodstuff data, and a novel CAE, monoethyl citrate (MEC, CAS: 4552-00-5), with a DF of 34% was tentatively identified. Overall, this study provides novel and comprehensive information regarding the pollution status of CAEs in foodstuffs.