Objective To investigate false positive interference from spices in hot pot base materials during the detection of thebaine using mass spectrometry, identify interfering matrix components, and optimize analytical methods. Methods The 62 kinds of commonly used spices in hot pot bases were collected. The false positive issues screened by BJS 201802 Determination method of morphine, codeine, papaverine, noscapine and thebaine in food were further analyzed by Fourier transform ion cyclotron resonance mass spectrometry combined with positive pressure electrospray ionization full mass spectrometry scanning. The potential interfering substances were locked through ion fragment analysis and verified. Results The results showed that the detection found interference peaks with retention times similar to those of thebaine in the extracts of bay leaves and pepper, which could lead to false positive results. The molecular weight of the interfering substance was 311.3812 ([M+H]+), with a deviation of less than 2 ppm from the theoretical value of thebaine (311.375), suggesting that it was an isomer. Through the detection of the suspected interfering substance, it was verified that Launobine and Pisatin had no interfering activity. Conclusion The alkaloid substances in spices have significant interference with the detection of thebaine. It is suggested to improve the specificity and accuracy of the detection by optimizing the mass spectrometry conditions, introducing nuclear magnetic resonance technology and perfecting the pretreatment process to avoid false positive misjudgment.

Dandelion is a medicinal and food plant in China, with a wide range of sources and rich nutritional and pharmacological values. Dandelion polysaccharide is one of the important functional active ingredients, and domestic and international studies have found that it has a variety of biological activities. This paper systematically reviewed the extraction and purification methods of Dandelion polysaccharides, analyzed the primary structural features of Dandelion polysaccharides, such as molecular weight, monosaccharide composition and chemical structure, and summarized and analyzed the biological activities and related mechanisms of Dandelion polysaccharides, such as antioxidant, anti-bacterial, immune regulation, hypoglycemia, anti-inflammatory and anti-tumor, etc., and explored the conformational relationship between the structure of Dandelion polysaccharides and its biological activities, which is aimed to provide the basis for the deep development of Dandelion polysaccharides in food and medicine. This study aims to provide important theoretical references for the development and application of Dandelion polysaccharides in food and medicine.

Objective To establish a method for the rapid determination of total flavonoids in tartary buckwheat by cerium dioxide/multi-walled carbon nanotubes/acetylene black (CeO₂/MWCNTs/AB) nano-electrochemical sensor. Methods The modified material and these nanoelectrochemical sensors were characterized by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The electrochemical behavior of rutin on the electrode surface was systematically investigated via CV. Critical parameters were optimized, including electrolyte type, pH, modifier ratio, coating volume, accumulation time and scan rate. Results One pair of well- defined redox peaks were observed at the potential of 0.54 V and 0.57 V, which indicated that the electrochemical oxidation and reduction reaction of flavonoid was reversible. The experimental conditions were optimized, the results as follows: B-R solution with pH 2.0 as the electrolyte solution, V_CeO2/MWCNTs:V_{acetylene black} as 1:3, amounts of modified material, 12 μL, enrichment time as 9 min. At these conditions, the oxidation peak current of flavonoid linearly increased with its concentration, I_p=0.793C+3.508 (r²=0.998), and the limit of detection was 6.5×10^-8 mol/L. The developed method was used to determinate total flavonoids content of tartary buckwheat, the recoveries were in the range of 99.46%-102.15%, the results were superior to ultraviolet-visible spectrophotometry. Conclusion The method is feasible for the rapid and accurate determination of total flavonoids in food with the advantages such as simple pretreatment time saving and convenience, low detection cost, high sensitivity and good accuracy.

Objective To establish a method for determination the fat content in flavored fermented milk containing thickeners by papain-gravimetric method. Methods Papain was used to reduce the adsorption of fat by casein in dairy products. The amount of papain added was 0.5 g, the enzymatic hydrolysis temperature was 65 ℃, and the hydrolysis time was 20 min. A mixture of ether and petroleum ether with equal volumes [25:25 (V:V)] was used to extract fat twice from the flavored fermented milk hydrolysate containing thickening agents. The extraction solvent was evaporated in a water bath, and the fat content was quantified by gravimetric method after drying in an oven. Results The determination of fat content in flavored fermented milk with thickener flavor was consistent with the label value, with a relative standard deviation of 0.40% and a maximum deviation of 0.05 g/100 g, which met the precision requirements of GB 5009.6—2016 third method for determination of fat in foods. Conclusion This method is simple to operate and conform to the concept of green analytical chemistry, compared with GB 5009.6— 2016 third method, it reduces the total volume of mixed ethers used, thereby minimizing harm to human health and environmental pollution. With good reproducibility, it can effectively determine the fat content in flavored fermented milk containing thickeners, providing robust technical support for quality control of such products.

Objective To optimize the subcritical water extraction process of Pollen pini polysaccharides based on genetic algorithm-neural network (GA-NN) algorithm and further explore its anti-fatigue activity. Methods Using broken shell Pollen pini as raw material, a response surface was designed through Box-Behnken test on a single factor basis, and a network neural model was constructed and optimized using GA-NN algorithm. Under the optimal process conditions, the anti-fatigue effect of polysaccharides was evaluated through mouse weight-bearing swimming test. Results The relative error and coefficient of determination (R²) of the constructed neural network model were 0.03267 and 0.98476, respectively. The genetic algorithm was iterated 60 times for subcritical water extraction of polysaccharides, and the optimal parameters were obtained as follows: Temperature 148 ℃, time 28 min, liquid to material ratio 40:1 (mL/g), pressure 5 MPa, and polysaccharide yield of 23.7893 mg/g. After verification, there was no significant difference between the actual value and the predicted value, indicating good accuracy of the model. The study on anti fatigue activity showed that compared with the blank group, the high-dose group of mice had a certain degree of increase in body weight, while there was no significant difference in other groups (P>0.05). Compared with the blank group, the swimming time of mice in the polysaccharide group was prolonged, the levels of blood lactate and urea nitrogen were reduced, and the reserves of muscle glycogen and liver glycogen were significantly increased (P<0.05). Conclusion GA-NN can effectively optimize the subcritical water extraction process of Pollen pini polysaccharide, and the polysaccharide has a certain anti fatigue effect.

Objective To investigate the contamination of fungal toxins in locally produced rice in Harbin Area, and conduct a risk assessment. Methods The content of aflatoxin B₁ (AFB₁) and ochratoxin A (OTA) in commercially available locally produced Daohuaxiang No.2 rice were detected using liquid chromatography-tandem mass spectrometry. Through Monte Carlo simulation, non-parametric probabilistic assessment methods and point assessment methods were employed to evaluate the dietary exposure risk of different populations in Harbin to AFB₁ and OTA through the consumption of rice. Results A dietary exposure model for AFB₁ and OTA has been established. This study found that both AFB₁ and OTA pose a high risk to children, especially those with high consumption levels, who had a greater potential risk of developing liver cancer through rice consumption. Conclusion The overall health risk of AFB₁ and OTA exposure through rice consumption among residents in Harbin is relatively low. However, there is a significant potential health risk for high-consuming children, which requires much more attention. Apparent health risks were not found for other populations.

Objective To understand the levels of veterinary drug residues in chickens and eggs in the diet of Xinjiang residents, and analyze and assess the health risks associated with exposure to veterinary drug residues in this region. Methods Veterinary drug residues were detected in chicken and egg samples from supermarkets and farmers’ markets in Xinjiang Uygur Autonomous Region from 2021 to 2023 by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and then combined with the data on the food intake of the residents of Xinjiang Uygur Autonomous Region, and then assessed the risk of dietary exposure by point assessment method. Results The detection rate of 19 kinds of veterinary drug residues in chicken and egg samples in Xinjiang from 2021 to 2023 was 23.3% (63/270), and the exceedance rate was 6.3% (17/270), and the difference in the detection rate of florfenicol was statistically significant by chi-square test (P=0.002), and the differences in detection and exceedance rates in the Northern, Southern and Eastern regions of Xinjiang were not statistically significant. The food safety index for chicken meat in Xinjiang were much smaller than 1, and the food safety index for veterinary drug residues in eggs were all less than 1, but the food safety index for ofloxacin, enrofloxacin, ciprofloxacin, diclazuril and florfenicolide were much greater than 1. Conclusion The risk of dietary exposure to veterinary drug residues for chicken meats and eggs in Xinjiang is small and in the controllable range.

Objective To establish an analytical method for the determination of flonicamid residues in tea and assess the dietary intake risk of flonicamid in tea. Methods Flonicamid residues in tea were extracted using acetonitrile, followed by dehydration and salting out with anhydrous MgSO₄ and sodium acetate. The supernatant was purified using anhydrous MgSO₄, C₁₈, primary-secondary amine (PSA), and graphitized carbon black (GCB) as adsorbents. Analysis was performed using ultra performance liquid chromatography-tandem mass spectrometry in multiple reaction monitoring mode with positive ionization. Quantification was achieved using matrix-matched external standards. Dietary intake risk assessment was conducted based on residue trial results and the dietary structure of the Chinese population. Results Flonicamid had a good linear relationship (r≥0.9999) within a certain concentration range. At levels of 0.01, 0.50, 20.00 and 30.00 mg/kg, the average recovery rates of tea (dry and fresh) ranged from 83.9%-93.6%, with relative standard deviations of 1.1%-5.3%. The limit of quantitation was 0.01 mg/kg. The final residue test and degradation test showed that the residual amount of flonicamid on tea was mainly affected by the combined effects of application dose and harvesting interval. The half-lives of flonicamid in fresh and dry tea in various regions were between 0.8-4.0 d and 0.8-5.1 d, respectively, indicating that it was an easily degradable pesticide. The results of the dietary assessment showed that the estimated daily intake of flonicamid through tea consumption for adults over 18 years old was between 0.74-0.81 μg/(kg·bw·d), which accounted for 1.05% to 1.16% of acceptable daily intake; combining the registration status of pesticides in China and the existing residue limits, the national estimated daily intake of flonicamid for the general population was 58.5193 μg/(kg·bw·d), which accounted for 83.6% of the acceptable daily intake. Flonicamid had low acute toxicity, and the probability of causing acute dietary risk was minimal. Therefore, there was no need to conduct an acute dietary risk assessment. Conclusion This method has simple pretreatment steps, high accuracy and high sensitivity, and can be used for the detection of flonicamid residues in tea. Upon evaluation, it has been determined that flonicamid does not pose an unacceptable risk to the general population.

Objective To investigate the current status of veterinary drug residues in eggs on sold in Banan District, Chongqing and assess the health risk of residues’ dietary intake residues. Methods In 2024, a total of 208 egg samples were randomly collected from markets and supermarkets in 10 towns and streets of Banan district. The residues of 15 kinds of veterinary drugs were detected using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The point assessment method was employed to calculate the daily estimated exposure and hazard quotient for dietary exposure risk assessment. Results The detection rate of veterinary drug residues in 208 samples of market eggs was 8.65% (18/208), with doxycycline showed the highest detection rate at 3.37% (7/208). The unqualified rate was 0.96% (2/208), with the unqualified samples mainly coming from unbranded bulk eggs sold in markets. The dietary exposure assessment revealed that the daily estimated exposure of veterinary drug residues ranged from 0.00013 to 0.03450 μg/(kg·bw·d), and the hazard quotient ranged from 0.00000 to 0.00872, significantly below the safety threshold. This indicates a low health risk associated with the intake of veterinary drug residues in eggs sold in the market. Conclusion Veterinary drug residues are detected in eggs sold in Banan District, Chongqing, but the residue is generally controllable and the health risk low. Special attention should be given to bulk and unbranded eggs, and standards for veterinary drug use and residue limits should be further refined.